4.1 System?

Hi Guys,
I'm considering the 990, but have a question.
I don't use a center speaker. Can I steer the signal to my left and right channels?
Thanks

Dean,

Most receivers and processors automatically downmix to however many speakers you have. During initial set up, you simply configure the 990 for whichever speakers you'll be using. Even if you're using only two speakers, none of the audio from 5.1/6.1 soundtracks will be lost.

I note that the 990 does not let me specify no center channel. However, for Dolby Pro Logic II and IIx, it allows mixing 0 to 100% of the center channel to the left and right channels. I consider this a bug: it should be possible to specify no center channel and have that signal mixed with left and right.

Not sure about the other modes.

Of course, the Tape/Out, Aux/Out, and Video1 Rec/Out always receive a two channel downmix.

Rene,

In the 990's speaker set up menu, can't you set the centre speaker to Large, Small or None?

I've noticed erratic behavior in the speaker setup menu. Often it won't let me specify "none" for surrounds, for example.

Seems to me it should always allow "None" as an option for any of the speakers and downmix as appropriate.

sdurani (and Prefect): No, I can't set center to None. I am stuck with Small if left and right are Small and Small or Large if left and right are Large. I even had a hard time disabling the surround speakers (I'm starting out with a 2.1 system -- my old strictly audio preamp died so I purchased my 990 sooner than I otherwise would have), though I succeeded by futzing around.

Navigating the speaker configuration menu is like a maze: the options for some speakers depend on the options set for others, and it's not clear what affects what.

Weird... I'm going to poke around a bit at this tonight, if my schedule permits (work's a bit crazy and the wife's a bit under the weather, though, so I've been keeping extra busy the last couple days). Maybe we can get a bit of a roadmap for the maze, and perhaps even suggest a few "shortcuts" through it that Outlaw might include in a software revision at some point.

Good idea, gonk.

I find it odd that one can't specify None for the center channel: the 990 is quite capable of mixing center with left and right: in Dolby Pro Logic II and IIx modes, one can even specify the degree of the blend. I'm not sure why this is not available in other modes. The blend of center to left and right should be 100% if the center speaker could be set to None.

Rene, When processing 2-channel material, the centre channel is derived by steering certain information out of the front L/R channels. It makes sense then that Dolby allows the end user to control the steering (i.e., how much is sent to the centre output).

With 5.1-channel material, there is no need for centre channel steering control. Think about it: 3 channels, 3 speakers; what's there to steer? Each front channel simply gets routed to its respective speaker.

With 5.1-channel material, there is no need for centre channel steering control. Think about it: 3 channels, 3 speakers; what's there to steer? Each front channel simply gets routed to its respective speaker.

Well, there is a need with digital matrix modes: what if there are less speakers than chanels? In particular, what if there is no center channel speaker?

I suppose that it might be the case that the analog matrix modes allow fine-grained control wheras the digital modes do not. But, I can't see it being that hard to mix 1/2 of center into each of left and right if there is no center speaker, regardless of mode.

Rene, If there is no centre speaker, then the centre channel content is split evenly between the front left & right channels. This is done automatically as a function of setting the speaker configuration, so there's no need to manually control centre channel steering.

BTW, what do you mean by digital and analogue matrix modes? All the matrix decoding and surround processing in the 990 is done digitally. PLII, PLIIx, Neo:6, etc, have always been implimented in the digitial domain (not analogue) from the very begining when they were introduced.

If there is no centre speaker, then the centre channel content is split evenly between the front left & right channels. This is done automatically as a function of setting the speaker configuration, so there's no need to manually control centre channel steering.

Except I can't seam to tell the 990 that there is no centre speaker!

BTW, what do you mean by digital and analogue matrix modes?

Dolby PLII and PLIIx are matrixed into two channels, no? Historically Dolby Pro Logic decoding was done in the analog domain, IIRC. So, I tend to think of matrixed multi-chanel audio as "analog", because it can be carried over a conventional stereo analog communication channel.

Dolby Digital and Dolby Digital EX (and other) formats are discrete 5.1 and 6.1 channel formats, often found on digital media. (Naturally, one could also have PLII and PLIIx on two digital media audio channels).

Digital processing is possible for all these formats. It's just that it was not done that way originally for plain old PL.

Rene, But that's a bug in the speaker configuration function. The solution is to fix the specific problem (i.e., allow the centre to be set as 'none').

End user control of centre channel steering is a useful feature when the centre is derived using steering, but it is not the solution to a speaker configuration problem. PLIIx can be applied to 2-channel and 5.1/6.1-channel material. It was when Pro Logic first came out, but since 1988 that decoding has been done in the digital domain. That's 17 years ago. Other matrix decoders (PLII, PLIIx, LOGIC7, Neo:6, Circle Surround II, etc) have all been digital since introduction.

But that's a bug in the speaker configuration function. The solution is to fix the specific problem (i.e., allow the centre to be set as 'none').

True, but if steering is available at all, what earthly reason should there be to not permit it in all modes? While likely necessary for PLII and PLIIx decoding gone awry (i.e. from ordinary stereo sources), I can see it useful for discrete sources for two reasons: (a) to accomodate for badly encoded material, with too much folded into the center (a PLII to DD transfer, perhaps, if unlikely?); (b) (which is more likely), a customer using a ribbon centre channel speaker, like the BG Radia 220i. Such speakers have a cylindrical dispersion pattern, and one would think that a centre speaker would have the ribbon driver mounted at 90 degrees to offer a dispersion pattern rotated with respect to its orientation (i.e. horizontal in the room). In fact, this is not done: a vertical (non-rotated with regard to the speaker) dispersion pattern is used for the benefit of listners straight ahead of centre. This avoids listeners to the side placing the center speaker off to the opposite side. But, the signal drops off rapidly to the sides (so instead of misplaced center, you get almost no center). Blending some of the center signal to left and right avoids this problem.

Some go so far as to argue that, with ribbon L+R mains, one should not have a centre channel speaker with high frequency response, or any at all. I can vouch for this: I'm currently running a 2.1 setup with Radia 520i mains and a sub, with a stereo downmix sent to the mains, and centre is dead centre even up to 30 degrees off-axis. One would think that centre would move closer to the nearer speaker in this case, and it does, of course, but the effect is attenuated by the fact that ribbon drivers' output falls off at 3 dB as one doubles the distance, not 6 dB, if one would have a spherical dispersion pattern (i.e. with a conventional speaker).

In lieu of a fix for the bug, it is frustrating to not be able to hack a fix by using centre channel steering in all modes.

PLIIx can be applied to 2-channel and 5.1/6.1-channel material.

Yes, but it always struck me as silly to use PLIIx to go from 5.1 to 7.1.

It was when Pro Logic first came out, but since 1988 that decoding has been done in the digital domain.

Granted.

I just always thought of matrixed (as opposed to discrete) surround modes as "analog" because they could be recovered/processed from two-channel analog matrixed mixes (i.e. the stereo audio connections from a DVD player). That was never done for discrete multi-channel audio carried over analog lines, because it was already decoded. I suppose the closest would be external bass management/processing for signals from 5.1 analog outputs from a DVD player, but even here, the decoding has already been done.

That's 17 years ago.

You haven't been around very long, have you? At my age, 17 years ago feels like "yesterday".

Rene, In this specific case, what you're asking for is the ability to control how front channel content is distributed amongst the three front speakers. With matrix decoding of 2-channel material, implimenting this feature is not difficult nor unreasonable. I have no problem with more options.

The centre channel is going to be extracted using matrix decoding technology, which is not 100% perfect. At some point, the processing has to choose how much gets extracted. It's a balancing act: too much extraction and you collapse the front soundstage to the centre; too little extraction and you're stuck with the very phantom imaging you're trying to avoid.

Since this balance can vary by source and, more importantly, personal taste, it makes sense to let users control the extraction level. With movies you can set it higher for clean dialogue; for music you can set it lower for a more continuous front soundstage.

But in the case of discrete multi-channel, what you're asking for is the ability to literally create a personal of remix the front three channels. After all, the three channels are normally routed to their respective speakers with no use (or need) of processing. So what you want to do is redistribute the contents of those channels.

The solution for you might be to actually buy an inexpensive mixer, where three channels come in and three channels go out, but the content is remixed (with the mixing being controlled by you). Remixing the front soundstage is not a solution to problematic speaker dispersion, any more than it is for a speaker configuration bug. Those problems should be dealt with, not covered up. Huh? Since there is no discrete 7.1 content, how else can you play back 5.1-channel material on a 7.1-speaker set-up? What specifically do you find "silly" about using PLIIx on 5.1 sources. That's interesting. I guess I never associated "digital" or "analogue" as having any relation to something as arbitrary as number of channels. I've always viewed them as being orthogonal and really don't see what one has to do with the other. But that's just me.

But in the case of discrete multi-channel, what you're asking for is the ability to literally create a personal of remix the front three channels. After all, the three channels are normally routed to their respective speakers with no use (or need) of processing. So what you want to do is redistribute the contents of those channels.

I agree that remixing the front three channels is useful when it comes to matrixed formats and is not "necessary" with discrete formats. However, I presume that, given the ability to remix for one (in the digital domain), it is trivial to remix for all. If that can improve support for 2.1, or 4,1 speaker configurations, why not offer it? I suppose one can argue that 2.1 or 4.1 systems are rare and so are not worthy of support, but again, if it's trivial to do, why not?

The bottom line is that I'd like the remixing capabilities to be orthogonal to the source formats even if they make more sense for some formats than others.

Remixing the front soundstage is not a solution to problematic speaker dispersion, any more than it is for a speaker configuration bug. Those problems should be dealt with, not covered up.

I would not consider cylindrical dispersion patterms problematic. In fact, they neatly address the problems of ceiling and floor bounce (for the mains) when compared to sperical dispersion patterns. A rotated dispersion pattern for the centre speaker is indicated as a matter of course. Remixing the front three channels would be a way to tweak the effect this has, but is not essential in typical rooms. I mention it as a possiblity, not a requirement.

The solution for you might be to actually buy an inexpensive mixer

No, the solution is a center channel speaker. (I think we'd agree here.) The BG 220i runs around $1800, however, so it will be a while before I purchase one. I would consider that a decent mixer would cost as much, unless I built it myself.

What specifically do you find "silly" about using PLIIx on 5.1 sources.

I'm of the opinion that the PLIIx processing would do more harm than good. I can understand PLIIx to go from matrixed two channel to five speakers and a sub. I can't understand the benefits of using it to go from five discrete channels to synthesize two more. I'm of the opinion that the resulting mangling of the surround channels as provided would do more harm than good. PLIIx on 5.1 to 7.1 strikes me as an excuse to justify two rear speakers instead of one.

I never associated "digital" or "analogue" as having any relation to something as arbitrary as number of channels. I've always viewed them as being orthogonal and really don't see what one has to do with the other. But that's just me.

History has a way of shaping one's perceptions. It's not so much the number of source channels, as it's the fact that matrixed channels were first distributed and decoded in the analog domain. So, when I read "matrixed", I think "analog". IIRC, the matrixing transform is not reversable, which means that encoding for matrixed distribution is a fussy, unreliable business, that also reinforces the "analog" adjective in my mind.

Who are you agreeing with? I said that if centre content is going to be extracted, then it makes sense to allow user control of the extraction level. The extraction process is ocurring anyway.

That's very different from remixing three discrete front channels by bleeding centre content into the left & right speakers. Who says a user adjustable remix capability is trivial? Besides, support for 2.1 and 4.1 speaker configurations already exists (and the solution is not a variable bleeding of the centre channel content, as you're proposing). Buy a mixer. After everything companies like Dolby and DTS have done to introduce a discrete centre channel to consumers, they're not about to create technology that lets you spread discrete centre content across the front soundstage. That goes against all they've worked for since the Pro Logic era. I would, especially based on your description: "the signal drops off rapidly to the sides (so instead of misplaced center, you get almost no center)".

The very point of using a centre speaker in home theatre is for the benefit of off-axis listeners. If you are using a centre speaker whose output basically disappears for off-axis listeners, then you most definitely have a speaker dispersion problem. Remixing the front three channels is not a solution to a center speaker with problematic dispersion. By bleeding the centre content to the other two speakers, you will be reproducing the dialogue in triple-mono.

This will not only introduce comb filtering and problems with dialogue inteligibility, but will cause the location of the dialogue to drift away from the display and towards the speaker that is nearest to you. After all, you no longer have the dialogue locked in the centre speaker only.

Again, this goes against everything that Dolby, DTS, THX and others have tried to do for dialogue reproduction at home. So don't expect any of them to come out with processing that allows you to remix the front three channels. A quick clarification on nomenclature: PLII creates up to 5 output chanels; PLIIx creates 6 or 7 output channels. The sub output is not created by the processing but by the bass management system in the receiver. There are several reasons for steering 2 surround channels over 4 surround speakers:

Localization: A car leaves the left side of the screen, the sound disappears to your left. A plane flier overhead, the sound disappears behind you. Even the two best surround speakers in the world can't be in two locations at once (at your sides and behind you).

Stability: No matter where you're sitting in the listening area, sounds that are intended to be heard from behind you are always heard from that direction. No magic involved, just a pair of speakers physically placed behind you (makes it hard for those sounds to come from any other direction).

Envelopment: Four surround speaker can literally 'surround' you better than two speakers can. What "mangling" are you talking about? If you were sitting in the sweet spot, right in between the two surround speakers, any correlated mono surround information would end up phantom imaging behind you. If you're out of the sweet spot, those sounds collapse to the nearest speaker.

PLIIx extracts those sounds and sends them to speakers behind you. Now even if you're out of the sweet spot, those same sounds will always image behind you.

Same exact directionality, just greater imaging stability. You really consider this "mangling"? That makes no sense. Dolby and DTS and THX were already recommending the use of two rear speakers for EX/ES playback. Dolby extended PLII to PLIIx because they noticed that 7.1 set-up were catching on with consumers. The fact that people were using two rear speakers was the justification for PLIIx, not the other way around.

Finally, despite your explanation, I still don't understand why you would deliberately refer to digital surround processing as "analogue". Again, it's probably just me.

Sanjay took my quote about remixing the front three channels out of context. I said I agreed it was useful for matrixed sound formats. I also believe it is useful for other formats when there is no centre speaker. So, if you can do it at all, why not be able to do it all the time for a 2.1, or 4.1 setup?

Contrary to what you say, the 990 does not support this in non-PLII modes because it does not allow specification of no centre channel. One way to do this is to allow a remix in all modes and, perhaps, set it to 100% center by default to left and right (50% each) for 2.1 and 4.1 configurations.

The need to remix stems from the speakers available, and not any defect in the discrete multichanel formats.

But, if you allow 0-100% remix in PLII why not in all modes, when there is a centre and 100% when there is none? Personally, when watching a movie alone in the "sweet spot" I prefer no centre channel dialog speaker.

The cylindrical dispersion patterns of planar magnetic speakers are not a "problem": they allow for greater sound levels at greater distances with less power because the SPL drops off by 3 dB for a doubling of distance, instead of 6. In their operational range of 150Hz to 40Khz, their distortion figures are amazing. Their dispersion pattern solves the problems of floor and ceiling bounce. Their one flaw is that they generally don't operate well below 250 Hz. However, they offer the big advantage of not requiring a crossover in the sensitive midrange area, common in small two-way and three-way speakers. They are usually combined with woofer arrays (like the Carver ALS, c. 1987 which combined three dipole 12" woofers with a 48" ribbon driver in each speaker), and tended to suffer from inefficiency problems (the Carver ALS were rated 86 dB/W/m) until modern magnets were developed (today 88-90 dB/W/m is common). Still, they like power, and clean power: cheap amps driven into clipping will destroy a ribbon.

The Radia 520i is designed to be crossed to a sub at 80 Hz, for example, and is rated 50-250 W.

However, the center channel dispersion pattern, if unaltered, will place dialog to the left of centre for right off-axis listners and vice-versa. Planar magnetic centre channel speakers contain difusing panels to offset this (and tend to be quite long, often more than a 32" set, to ensure off-axis response). This could also be achieved with a L-C-R blend, if available for other reasons. Either deal with the problem mechanically, or electronically.

The benefit of all of this is amazing sweet spot (which tends to be quite large, actually) imaging. In fact, I've heard PLII material over two stereo planar magnetic speakers with phantom sounds from the sides and rear, if the material and room is just right.

What particular "context"? Apparently you think this features is useful "all the time" (see quote above).

I'll ask again: who is it you're agreeing with? Who else in this thread has said that remixing the front three channels is "useful for matrixed sound formats"?

2.1 and 4.1 set-ups are already covered by initial speaker configuration. The centre channel content is reduced by 3dB and split equally to the front L/R channels. Nothing further needs to be done.

You seem to be under the impression that "remixing" is happening during PLII matrix decoding, when that's simply not true. Only when a centre channel is being extracted can the extraction level be chosen by the user. This is very different from a remix function that would bleed discrete centre channel content to other speakers on a variable basis. That's a bug, which Outlaw Audio will hopefuly deal with. The solution is to fix that bug, not re-mix the source material. There is no "need to remix stems". If the problem is the speakers, then that's what should be addressed. The solution is a centre speaker that actually does the job, not some re-mix function that spreads the discrete centre content across three speakers. Because there is no re-mixing (i.e., re-directing discrete centre content) going on in PLII. This is a feature you've invented in your imagination and are now lamenting for not applied to other modes. It doesn't exist.

And for situations where you have a discrete centre channel but no centre speaker, then 100% of the centre channel content is sent to the L/R speakers. Hey, I'm just going by what you described earlier. Any centre speaker that's essentially useless for off-axis listeners is a real "problem" for any home theatre.

I'll ask again: who is it you're agreeing with? Who else in this thread has said that remixing the front three channels is "useful for matrixed sound formats"?

Why you did, Sanjay: "When processing 2-channel material, the centre channel is derived by steering certain information out of the front L/R channels. It makes sense then that Dolby allows the end user to control the steering (i.e., how much is sent to the centre output)."

I consider that remixing.

You go on to say: "You seem to be under the impression that "remixing" is happening during PLII matrix decoding, when that's simply not true."

Well, yes, I am under that impression. Taking a variable amount of L and R and no C (because there is none), and deriving new L and R and C strikes me as remixing. Perhaps we are stuck on terminology.

Only when a centre channel is being extracted can the extraction level be chosen by the user. This is very different from a remix function that would bleed discrete centre channel content to other speakers on a variable basis.

I don't consider it any different. Consider a 100% extraction of available centre channel signal from a PLII matrixed source. 0 to 100% of that could be mixed back to L and R with anything not mixed back sent to C. Now I agree it likely is not done that way (100% extraction and remix), but it certainly could be, and that would allow for a remix from three discrete sources as well, and therefore a 100% mix of C into L and R for 2.1 and 4.1 setups.

Basically, I'm expecting that the PLII centre channel extraction algorithm, if coded correctly, could do double duty as a downmix from LCR to LR. It's simply a case of software refactoring. The only way this would not work would be if the PLII centre channel extraction algorithm were lossy, but even that could be dealt with by keeping the parts extracted from the left and right channels separate until finally combined to form a derived centre.

That's a bug, which Outlaw Audio will hopefuly deal with. The solution is to fix that bug, not re-mix the source material.

And how else can the bug be fixed, except by remixing the source material? To wit, 50% of C added to L and 50% of C added to R, for 2.1 and 4.1 setups.

Because there is no re-mixing (i.e., re-directing discrete centre content) going on in PLII.

But whatever is going on is idempotent to such a remix and so may be considered as one. Consider L'=L-eLc, R'=R-eRc, C=eLc+eRc, where e is the "extraction level". One can certainly say L"=L-Lc, R"=R-Rc, C=eLc+eRc, L'=L"+(1-e)Lc=L-Lc+Lc-eLC=L-eLC, R=R"+(1-e)Rc=R-Rc+(1-e)Rc=R-Rc+Rc-eRc=R=eRc. That is, derive full centre channel "halves" from a PLII matrixed source, and then remix part of them back to their source channels. For a discrete C, Lc=Rc=C/2.

2.1 and 4.1 configurations then just fix the value of e at 0 (or, for complete remix control, permit it to remain variable).

I am not suggesting the 990 does it this way. I am suggesting that it could, and it would kill several birds with one stone.

And for situations where you have a discrete centre channel but no centre speaker, then 100% of the centre channel content is sent to the L/R speakers.

Exactly! (At least that's what's supposed to happen). Sounds like remixing to me.

Hey, I'm just going by what you described earlier. Any centre speaker that's essentially useless for off-axis listeners is a real "problem" for any home theatre.

The BG 220i is hardly useless for HT. The ribbon driver alone is problematic unless oriented properly within the speaker (which it is, but can be special ordered "the wrong way", IIRC, for vertical mounting of the 220i). I was merely speculating how a remix of the front three channels could also be used to combat a driver oriented "the wrong way" (for example, if one had three identical R32i speakers in the front wall without reorienting the centre ribbon), as a hack, in the same way that it makes 2.1 and 4.1 setups a snap.

This is not as useless as one might think, as it permits accomodation of the degree to which one has viewers off-axis: imaging is shot, to some degree, with a center channel speaker, for the lone listner in the sweet spot. Rarely is dialog spot on centre, and anchoring it there collapses the soundstage for the sweet spot listner to one degree or another.

Actually, I didn't. In fact, quite the opposite: I went out of my way to repeatedly clarify that it is not remixing (especially not what you're proposing with the centre channel content being spread to all three front speakers).

With PLII, there is no centre channel unless one is extracted by the processing. Since the extraction is already ocurring, it makes sense to have some user control over the extraction level.

This is very different from the remixing you're talking about, where no additional channels are created but the contents of the front three channels are literally redistributed. You can "consider" it anything you want. That will allow you to claim that the 990 has a feature (which it really doesn't) and then complain when that feature is not present for other modes.

If you actually admit what PLII is doing, then your complaint falls apart because you realize that there isn't any remixing going on to begin with. Again, you can "consider" it anything you want, but they are in fact different processes. Extracting a centre channel where there was none is different from redistributing discrete centre content to other channel and mixing it into the content that already exists in those channels. No, it's not "simply a case of software refactoring." Matrix extraction is different from downmixing. The above describes standard downmixing of three channels to two. But this is different from what you've been proposing, where you start off with three channels and end up with three channels, except with the contents redistributed. I don't understand what you mean by the above. Are you saying that imaging is shot when using a centre speaker for a listener in the sweet spot? And how does anchoring the dialogue to the centre channel end up collapsing the front soundstage?

The above describes standard downmixing of three channels to two. But this is different from what you've been proposing, where you start off with three channels and end up with three channels, except with the contents redistributed.

It is not different. Two channels of speakers is just a special case of three with the level of the third set to zero. Three input channels available for remixing is independent of whether some of those channels are derived from others, or not.

You appear to distinguish between special cases and the generic case, calling them different things. If we prefer, we can call what I propose a matrix transform of a vector function of the input channels. I prefer the term "remixing", to that actually.

I don't understand what you mean by the above. Are you saying that imaging is shot when using a centre speaker for a listener in the sweet spot? And how does anchoring the dialogue to the centre channel end up collapsing the front soundstage?

Yes. Add a center channel speaker when you have dialog slightly left or right of centre (which can be properly imaged with two front speakers for a listner in the sweet spot), and the dialog moves more toward the center.

This helps off-axis listeners, but hurts the listner in the sweet spot. Therefore, it should be tunable to the degree one has off-axis listeners (i.e. how far off-axis). I suppose a single center channel with a fixed level (relative to the others) suffices for most theatres, but I have never found one necessary when listening/watching alone. I do expect however, that a two channel downmix of discrete LCR sources might be worse than a stereo recording as far as placing dialog: when not downmixing 5.1 to stereo, I hear very little left and right channel dialog. With stereo recordings, I hear speakers (as in people speaking, not transducers) located quite precisely when seated at the sweet spot.

In the extreme, I've seen studies that suggest anything more than two front speakers is hogwash, and I have recordings with back to front and side to front and back effects that bear this out. But, they only work in just the right room, at the sweet spot, suggesting a lone viewer/listener with time and money for precise speakers and room treatment. Google for "phase accurate speakers" for an introduction to this kind of "voodoo" (as most discount it). The effect, however, while perhaps not as pronounced or important as proponents might suggest, is very real.

No, I'm distinguishing between matrix decoding (where a centre channel is extracted from other channels) vs downmixing (where the centre channel is combined with other channels). You can buy an inexpensive analogue mixer from pro-audio companies like Behringer to do the type of downmixing you're interested in. However, it won't do matrix extraction. They're two different things. I just tried this with a couple of sources that have dialogue moving across the front channels and the dialogue did not move towards the centre. One was a discrete 5.1 source (Monsters, Inc) and the other was a 2-channel source (Bad Day at Black Rock). I compared playback with and without a centre speaker. You may have a problem with your system.

No, I'm distinguishing between matrix decoding (where a centre channel is extracted from other channels) vs downmixing (where the centre channel is combined with other channels).

Then we have a difference in terminology. I consider downmixing the (usually linear) mixing of upstream data to be sent downstream, as in a pipeline process. The number of channels need not be reduced. Thus, a three channel to three channel downmix is possible.

What you say about extraction is true, but, because PLII extraction permits control over the distribution over the front three channels, I separated into a fixed extraction (which is likely a non-linear transformation) and a linear mixing transformation. It is the latter that I would like to see provided in general.

You may have a problem with your system.

Since I only have a 2.1 setup at the moment, I don't have a system to have a problem with. However, your observation is interesting, particularly with PLII extraction (I would expect a discrete mix to fare well).

Are you suggesting that a PLII extraction to two front speakers (no centre) is no different than a PLII extraction to three front speakers, including a fully extracted centre (i.e. what would be a "normal" extraction setting)? If so, how far apart are your two front speakers? My 520i sit 12 feet apart, and, on stereo test material, can image quite precisely between them, and to some small degree, outside them, at the sweet spot (not that this is surprising).

The "down" in downmixing refers to the fact that you're reducing the number of channels. The opposite of upmixing (e.g., from 5 channels to 7 channels). If you're going from 3 channels to 3 channnels, then that is not a downmix.

As for what PLII does in the front channels vs what the 'no centre' setting does, it's quite different:

PLII does matrix decoding and logic steering. First, correlated mono information is copied and sent to the centre output. Next, anti-phase cancellation signals are generated and sent to the three outputs. This surpresses L/R stereo info in the centre channel and surpresses centre info in the left & right channels. As part of the logic steering process, the gain of the three channels are ridden based on where sound is dominant in the front soundstage. This aids the cancellations signals in enhancing the sense of channel separation.

Compare that process to setting the speaker configuration to 'no centre', where discrete centre info is sent to the left & right speakers and the centre output is turned off. To be blunt: this is the electronic equivalent of a simple Y-splitter.

I don't see how you can consider these two processes to be even remotely similar. Making the downmix function variable would require actual mixing capability, which is why I suggested you get an inexpensive analogue (pro-audio or DJ) mixer. Wait a second: you're only using two speakers? Rene, have you been guessing about some of the stuff you're claiming or have you actually tested those things out (as I did last night)? What extraction are you talking about? With two front speakers, PLII is not extracting any centre content. If you're using two speakers total (no surrounds), then PLII is not doing any processing whatsoever. Two channels, two speakers; what's there to process? You simply route each channel to its respective speaker.

Wait a second: you're only using two speakers? Rene, have you been guessing about some of the stuff you're claiming or have you actually tested those things out (as I did last night)?

I performed a mathematical analysis. On the BG dispersion patterns (and those of planar magnetic speakers), I refer you to the BG site (www.bgcorp.com). As I own a pair of Radia 520i as well as Carver ALS, I am familiar with them personally.

I note that the PLII extraction with variable centre channel level can be decomposed, mathematically, into a non-linerar transform followed by a linear 3x3 matrix multiply. I refer to the latter as downmix, because that's what it's typically used for. Use "remix" if you prefer. That remix can be used for extracted as well as discrete channels.

The bottom line is that you are saying that matrixed sound is decoded by Flcrs(X) and remixed discrete sound is handled by MY. No disagreement.

I'm noting that this can be transformed to Flcrs(X) = M*F'lcrs(X) and M*Y = M*Y, refactoring M. M, of course, is a linear transformation (i.e. remix) matrix, Flcrs() and F'lcrs() being a non-linear vector function over a two dimensional (stereo) vector argument, and Y being a discrete signal vector.

Given that M exists for discrete sources (to map channels to speakers) and can be derived for matrixed sources, I say, why not make the processing offered by M orthogonal to the encoding format?

What I'm not hearing from you (and what might very well be the case), is that there is no linear decomposition M*F'lcrs(X) = Flcrs(X) possible to achieve the degree of center channel extraction for PLIIx sources. I was under the impression that such a linear decomposition did, in deed, exist.

What extraction are you talking about? With two front speakers, PLII is not extracting any centre content. If you're using two speakers total (no surrounds), then PLII is not doing any processing whatsoever

On the 990 it most certainly is, because I can't tell it there is no centre speaker. I can either tell the 990 to downmix to stereo (which is idempotent for PLII, as you noted and it is not clear if the 990 will extract and remix or just leave the signal alone), OR tell the PLII processor to extract none of the centre.

If M*F'lcrs(X) = Flcrs(X) decomposition is possible for PLII, then there is no reason why the 990 can't just let me control M independent of source. It lets me do this for some values of M knowing how many speakers I have for discrete sources with one fixed value of M for each speaker configuration, and several values of M for PLII decoding, controlling centre channel extraction. If PLII-style control of M was available for all sources, then it would offer a workaround for the bug where I can't specify the lack of a centre channel speaker.

Sure, I can select stereo downmix from the 990, but it defeats this when it sees a PLII encoded source! So, there are two bugs consipring against me. If Outlaw had refactored M as above, I could use creative settings of M to get around the bugs.

I suppose, I can get around the problem until my BG 220i arrives by setting the centre channel extraction to none for PLII matrixed sources.

The answer is not an 'inexpensive' analog mixer (I have not found good mixers to be inexpensive -- the BG 220i is by far the cheaper and more correct solution). The answer is a centre channel speaker.

There is no reason you can't do that but it would require the 990 to have an actual mixer built-in (something different than the simple Y-splitter functionality it currently has). There is no interest (aside from you) in such capability because the goal of home theatre technology/processing has been to localize and stabalize centre content, not smear it across three speakers. It's the antithesis of what companies like Dolby and DTS want to do with a discrete centre channel. Again, that's a bug. On a normally operating procesor, PLII does not extract centre content when only two front speakers are configured. That would be the equivalent of discarding centre content (it's being extracted but not played back). Again, PLII does not do any downmixing. The Centre Width parameter can be adjusted to vary the amount of centre content extracted. But PLII has no capability of combining centre content with other channels. OK, I'll bite. When you do get a centre speaker, how will you suddenly have the capability to variably bleed discrete centre content into the L/R channels? Is the centre channel somehow going to change the processing capabilities of the 990 to add the remix function that you want?

This is an interesting thread to say the least. I'm wondering why Rene's 990 doesn't allow selecting NONE for the center channel. Is there anyone else who has this problem? I would think Outlaw would exchange the unit if it were a defect of that unit alone.

Unless it's a bug with the model, not Rene's specific unit?

OK, I'll bite. When you do get a centre speaker, how will you suddenly have the capability to variably bleed discrete centre content into the L/R channels? Is the centre channel somehow going to change the processing capabilities of the 990 to add the remix function that you want?

Obviously, I won't have that capability.

But, if remixing were implemented as I propose, it would have (a) provided a workaround for the no centre speaker bug; (b) allowed fine-grained control over the front soundstage which might be useful for some; (c) been easier to document since remixing would be orthogonal to source format. I'm of the opinion that this is just a software implementation issue, and not constrained by hardware. I'd like to know if that assumption is not correct.

A centre channel speaker would, of course, eliminate the need for the hack, but the ability to experiment with front channel remixing would be handy to see the tradeoff between sweet spot imaging and off-axis centre channel anchoring.

Yes, yes, an analog mixer could be used to do this. But, if the 990 has all the capabilities to provide such a mixer in the digital domain, why not expose them to hackers?


I'm also guessing that the inability to specify no center speaker is a software bug with the model. Does anyone know otherwise?

OK, so since a centre speaker won't give you the capability you've been proposing, it will have to be some sort of mixer; either outboard or built into your surround processor. Just my opinion, but: (a)The bug should be fixed and not worked around; (b)Spreading (fine-grained or otherwise) a discrete centre channel to three speakers is a bad idea because of reasons mentioned previously; (c)What are people going to documenting in their home theatres? I'm guessing that the hardware is already in place, since discrete centre and surround content can be re-routed to the front speakers (when centre and surrounds are set to 'none'). The only thing you need is some sort of gain stage in the re-routing circuit to vary the amount and/or volume level of sound being re-routed to the front L/R speakers. Basically a mixer, preferably done in the digital domain, placed right after the DD or DTS signal is decoded/unpacked but right before bass management and time alignment. Because home theatre manufacturers and users are not interested in wanting to "experiment with front channel remixing". They just want to watch a movie, where dialogue comes from the screen and not in triple-mono from all three front speakers.

Just my opinion, but: (a)The bug should be fixed and not worked around;

Both should be possible, that is, it should be possible to work around the bug until Outlaw provides an official fix. If variable PLII centre exraction were refactored to full extraction, with variable remixing (available regardless of source format), instead of variable extraction for PLII only, and fixed remixing (to accomodate varying number of speakers), a hack would be available for the end user. To boot, channel to speaker mapping just becomes another M (or M') transformation matrix.

Restricting variable mixing to those modes for which it "makes sense", i.e. as variable PLII extraction and making downmixing separate, makes the documentation more complicated, because one has to say, in effect, "in mode ... you can do ...; in mode ... you can do ... and ..., but not ...; in mode ... you can do ...", the assumption being that the reader can better understand a plethora of special cases instead of a series of orthogonal processing steps, even if some combination of those steps might not make sense.

Personally, I don't buy that line of reasoning. Outlaw could always offer a "novice" and "expert" mode with the "novice" mode disabling possible but likely not useful combinations.

It makes the underlying processing much simpler to code because it becomes an independet set of steps without needing "special cases" to forbid things that don't "make sense". Each step has it's own independent configuration settings, and only "novice" mode has the knowledge to gate "illegal" combinations of configuration settings.

It also could allow customers to define their own set of options for each step, allowing one to eliminate options that one does not use. Of course, always offer factory default "novice" and "expert" (and perhaps "maintenance" modes).

Because home theatre manufacturers and users are not interested in wanting to "experiment with front channel remixing". They just want to watch a movie, where dialogue comes from the screen and not in triple-mono from all three front speakers.

And that is optimized for a particular distribution of on-axis and off-axis listeners/viewers.

I'd like my pre/pro to have connections for seat sensors and remix appropriately depending on where the audience is sitting (the default being, well, as it stands).

While it might be outragous to suggest that Outlaw provide such functionality and hardware interfaces, the combination of the RS232 status and control port, and a dedicated microcontroller with seat sensors could do it if the 990 exposed a control mechanism for it's internal digital mixer. A separate analog mixer, controlled by the microcontroller would work too, but why on earth should I need that when there's a perfectly good digital mixer implementation likely present in the 990?

My overall point is that Outlaw should expose all the internal mixing and switching capabilities of the 990 even though its internal software limits how they are used to "keep it simple". Perhaps only via the RS-232 interface, so novices can't "mess things up by accident".

This opens up control of the unit to hackers, who might develop really useful control software models, some of which might eventually get folded back into internal software upgrades offered by Outlaw.

Win for hackers, win for Outlaw (who get free control software development), and win for future customers.

I suppose that that is the question. I ask because I am only using left and right fronts and no center and I am able to set the center to NONE on my 990.

How, exactly? I've tried to no avail, and I can't believe my unit has buggy or old firmware.

FWIW, my front speakers are set to "small" and I have a sub. No surround speakers (yet) -- I'm basically using the 990 as an analog preamp, DAC, and multi-channel audio decoder.

No one is "restricting" variable mixing. The feature isn't there because there's simply no use for it. You're confusing extraction with mixing. Extraction is already being used in the matrix decoding modes, so allowing it to be variable is easy.

There is no mode that uses variable bleeding of discrete centre content. Since it's not there to begin with, how can it be restricted to certain modes? It doesn't exist, period, despite what you may want to believe.

Also, it doesn't add any complication to the documentation of the modes. Different modes have different features. You just have to deal with it. Outlaw isn't in the business of designing surround processing and lossy compression technologies like PLII and DD (respectively). They're buying those technologies off-the-shelf from Dolby. Likewise with DTS's technologies.

Outlaw can't change how those modes work (even if they knew how to) because those are licensed items and as such have to adhere to the specification of the license. Outlaw isn't holding back; the 990 comes with practically everything Dolby has to offer for home theatre systems. Bleeding discrete centre content to other speakers helps neither on-axis nor off-axis listeners. The triple-mono result induces comb-filtering and smears localization. That's why no one has done it. It's a useless feature and not worth wasting time/resources implementing in home theatre products.

Rather than crunching numbers for a simulation of what you expect to hear, you really ought to try actually listening to the results of what you're proposing. ...and robots that lift the speakers up and down depending how tall or short you are. That would really be useful (and easy to implement). There isn't a mixer present in the 990. Just because you believe that one is there doesn't mean that reality will somehow accomodate you by making a mixer suddenly appear in the 990. Now it's "hackers"? (I feel like I'm in a sitcom but just don't know it yet.) What can I say, except that Outlaw and Dolby and DTS are not manufacturing products designed with software hacking in mind.

You're confusing extraction with mixing. Extraction is already being used in the matrix decoding modes, so allowing it to be variable is easy.

Sigh. Unless said extraction is non-linear, full extraction followed by variable mixing can have the same effect, and allows leverage of an existing mixer.

There is no mode that uses variable bleeding of discrete centre content. Since it's not there to begin with, how can it be restricted to certain modes?

All the pieces are there: extraction, and mixing (how else would one mix to the appropriate number of channels, and implement the variable balance between side and back surround channels if there was not a continuously variable mixer?).

If a variable extraction to centre is available, a fixed extraction to centre is available, and since a mixer exists, it can be used whether the centre is discrete or extracted. It's a simple issue of software refactoring.

Outlaw can't change how those modes work (even if they knew how to) because those are licensed items and as such have to adhere to the specification of the license.

No, but they can refactor bits out of the implementations! I doubt the licenses prohibit this -- they likely include a reference implementation and a suite of tests that the implementation must pass. What is licensed is not likely to be code specific to the processor in the 990, but rather a right to implemented a patented process, along with access to intellectual property to facilitate such an implementation.

Also, it doesn't add any complication to the documentation of the modes. Different modes have different features. You just have to deal with it.

Have you never heard of the benefits of software refactoring? The common aspects of different modes can be refactored. In fact, I'd bet that, in the 990, they are, but that this is hidden from, the user.

If you can refactor a mixer, you can expose it fully, and common mixes to specific number of speakers just becomes a special case of a generic parametrization. The questions are only whether that generic access and the refactoring is exposed via the user interface or if the unit is crippled.

There isn't a mixer present in the 990.

And I say, based on what the 990 does, there is. It just isn't fully exposed. I can't believe that the 990 would used fixed hardware mixing after all that software decoding (which is more computationally intense).

The triple-mono result induces comb-filtering and smears localization.

Well, this is a sensible argument. But you'd get that with partial PLII centre extraction, no?

Actually, with the BG Radia 220i, you do get smearing of localization: the damn thing is more than 32" wide and transmits along its length with a cylindrical dispersion pattern. Centre appears to come from the display, not the centre of the display. You don't get the comb filtering problems with the one speaker alone, but it is possible with a bad (i.e. relatively equal) bleed between separate L, C, and R.

Now it's "hackers"? (I feel like I'm in a sitcom but just don't know it yet.) What can I say, except that Outlaw and Dolby and DTS are not manufacturing products designed with software hacking in mind.

Well, they should. They're already catering to early adopters who think nothing of dropping $1100 to buy something over the Internet. They'd get feature and bug fix prototyping for free.

It can have the same effect, but you'd need a variable mixer - which doesn't exist in the 990. All the pieces aren't there: extraction exists, variable mixing does not. You're looking at the electronic equivalent of a Y-splitter (when centre speaker is set to 'none') and considering that a mixer. It's not. You're starting from a false premise. Since extraction is already occuring, it is easy to make it variable. But mixing doesn't exist, so there is no way to modify (e.g., make variable) something that's not there to begin with.

As I mentioned earlier, you are free to believe that a mixer exists in the 990. But living in an alternate reality will force you to come up with bizzare reasons why this phantom mixer is not being used. To rationalize your position, you'll have to resort to conspiracy theories about 'secret' capabilities and purposely 'disabled' features. OK, so I was close. You called them "hidden" and "crippled" (instead of 'secret' and 'disabled', respectively).

But yes, you are of course correct: certain features were conspired to be hidden from you. Note that others can set their centre speakers to 'none' but you can't. You should have seen the Outlaws gathering at the Grassy Knoll, whispering: "Well, that went off pretty smoothly! Now about this Rene guy..." Early adopters? The surround processing technology in the 990 is mature; nothing there on the bleeding edge (even PLIIx has been around for almost two years).

In any case, as tempting as it is to have "feature and bug fix prototyping for free", I'm glad that consumer electronic companies don't design their products to accomodate hackers.

All the pieces aren't there: extraction exists, variable mixing does not. You're looking at the electronic equivalent of a Y-splitter (when centre speaker is set to 'none') and considering that a mixer. It's not.

Oh, for Pete's sake! If one can code C' = xC, L' = (1-x)C/2+L, R'=(1-x)C/2+R, for x either 0 or 1, one can code if for x between 0 and 1. DSPs and hybrid processors do pretty good fixed and floating point math these days (likely necessary for DD decoding anyway).

The only assumptions I make are that (a) the 990 does decoding and processing in the digital domain, (b) it has fixed and/or floating point capabilities, and (c) it can combine data from independent channels.

What part of the linear algebra are you having trouble with?

You called them "hidden" and "crippled" (instead of 'secret' and 'disabled', respectively).

Yes, because I believe they exist in code that any reasonable programmer would refactor in such an application, but are not exposed to the end user. 'secret' is your word to imply a conspiracy, not mine. I do not believe the lack of access to this funcionality was intended to thwart experimentation, but rather to protect the unsophisticated end user from themselves -- I see no malice in the restriction.

Early adopters? The surround processing technology in the 990 is mature; nothing there on the bleeding edge (even PLIIx has been around for almost two years).

I was referring to the practice of plunking down over a thousand dollars for a product over the internet, sight unseen, on the reputation of the seller.

In any case, as tempting as it is to have "feature and bug fix prototyping for free", I'm glad that consumer electronic companies don't design their products to accomodate hackers.

Actually, increasingly, companies do this.

Outlaw can by offering a test mode which provides greater control capabilities over the unit via it's serial port. This is useful for automated testing in the factory. It would also be useful for hackers.

Note that others can set their centre speakers to 'none'

And I've asked for a description of how (starting from a reset unit). I can't, and no one has responded. I do not believe that the firmware in my unit is somehow different from stock -- that's your conspiracy theory. (It would be nice if there was a way to obtain the firmware version from the unit). Either I'm doing something wrong, or there is a "trick" to specifying two small L+R speakers and a sub.

The part where you calculated that a mixer exists in the 990 when none does. This is like earlier when you calculated that off-centre dialogue would move towards the centre when using a centre speaker (but actual listening demonstrated otherwise).

Of course, you are free to believe things like a mixer exists in the 990 or that "imaging is shot" when using a centre speaker. But given a choice between your "mathematical analysis" and reality, I'll opt for the latter (which doesn't support any of your above claims). Really? Which A/V companies are allowing software hacking of features such as surround processing and/or speaker configuration? Hackers aren't their market.

Really? Which A/V companies are allowing software hacking of features such as surround processing and/or speaker configuration?

Any one based on a Linux platform and conforming to the GPL. TiVo comes to mind, though strictly speaking that isn't an A/V company.

RokuLabs, which makes an HD playback device (HD1000 a.k.a. Photobridge) is another, though the Photobridge (don't let the name fool you, it will play HD MPEG2 video streamed from a PC, PS and TS) only has digital and two channel analog outputs.

Finally, there is a bunch of free (as in GPL) sofware available to do DD decoding on a fast enough PC (not requiring a DSP), though that starts to run up against possible patent violations.

As for adding a centre not destroying dialog imaging, I disagree. I don't want the dialog 1/4 of the way right from the centre creen to appear at the centre of the screen. Stereo miking works fine for the sweet spot.

"...isn't an A/V company", "patent violations".

Rene, you're not helping your case. Those companies are not your typical US or Japanese receiver/pre-pro manufacturers, nor are they licensors of surround processing technology like Dolby Labs and DTS are. None of the regular A/V companies are offering products designed to accomodate hackers. It doesn't. I named two sources with panned/off-centre dialogue that I tested and neither of them exhibited any collapse towards the centre when I was using a centre speaker (vs configuring the centre speaker as 'none'). Yes, yes, your "mathematical analysis" shows that it does. But you really ought to get an actual centre speaker and try it out in the real (physical) world.

We appreciate everyone's input and suggestions with regards to issues encountered with the Model 990. Each of your comments about potential software issues is being tested in our lab, and we are examining all of your requests for added features and functionality. This feedback will enable us to work with the Model 990's engineering team so that a software upgrade can be developed. Please understand that our goal is to deal with as many of your concerns as we can, but in some cases it is possible that a limitation in the hardware platform, rather than operating software/firmware may limit our ability to fix a particular item.

Please understand that the development of a software update is not an overnight task, as we must not only get the new system, but do a complete re-validation of the entire program to be sure that we do not "break" anything in the process of adding new functionality or fixing a bug. We'll keep you posted along the way as to our progress.

Regards,

The Outlaws

Who cares if a purchaser of a product uses it to violate a patent? It isn't the vendor's problem (unless that's the sole purpose of the product, and even that is a questionable legal position).

Perhaps your computer should be removed from you lest you write a program that violates a patent, and nothing be modifiable. Your car's hood should be welded shut lest you try to change the oil yourself.

The Roku HD1000 is fairly open, provides HD TS and PS playback, and has the capability for code on it to intercept the audio bitstream, regardless of encoding.

Many have written useful extentions to this platform, with the blessing of the manufacturer, and have enhanced it's functionality greatly as a result.

I could note that the OSS community has produced a hackable A/V component via MythTV and a stock PC, but then you'd likely argue that it isn't "ordinary", or an "A/V" component", or manufactured in the U.S./Far East. Perhaps that you'd argue it wasn't build in a particular city, and discount it on those grounds.

Even then, what about the MCE? It comes as close to an "ordinary, made in the USA, A/V component" as it gets and, though not actively encouraged by the manufacuter, is hackable.

The bottom line is that some manufacturers of consumer electronics are embracing and encouraging hackability of their products, and I believe that Outlaw could benefit from this same philosophy and this could result in workarounds being available for bugs discovered in the field sooner rather than later.

...in some cases it is possible that a limitation in the hardware platform, rather than operating software/firmware may limit our ability to fix a particular item.

Two things would be very nice to know:

1) What reported bugs have been verified by Outlaw (e.g. my inability to specify no Centre speaker)?

2) What IS the hardware architecture, at least in sufficient detail so an engineer could determine whether a particular feature/bug could be implemented/fixed in software? At the very least a switching/mixing/multiplexing diagram would make clear what kinds of transcoding to which outputs is/is not possible.

Rene:

I think you are answering your question for yourself without realizing it. Outlaw is in a segement of the market where people want to tinker with settings and equipment placement (speakers) but not have to deal with the arcane world of software. It would appear that they do a good job for that type of customer. It doesn't mean you are right or wrong, it simply means that you are looking for something that I'd guess 99.9% of their customers don't want, don't need, and wouldn't know what to do with if it was there.

IF you have the desire to fool with software, than by all means avail yourself of the products you have mentioned that do that. Remember, as a software professional, your interests and knowledge are considerably different from the average "I just want to watch my home theater and not have to think about it" person.

The risks to Outlaw of having people mucking around with the inner SW of the 990 or any other product strongly outweigh the benefits. I'd hate to be Scott or one of their other customer service people on the other end of the phone when a customer calls after loading hacked software that has a bug in it that might corrupt the microprocessor or memory -- or ever worse. The novice will make their life difficult and insist that Outlaw fix it even though it isn't their fault.

One more thing:

Unlike in OSS land, it may well be the case that there are aspects of the 990's HW platform that they would not want to reveal. WHy should they tell their competitors what they do and how they do it? OSS is a game; Outlaw is a business where I have to presume they would like to make money and stave off competitors if they have something unique.

Podboy:

One does not have to reveal all with OSS, contrary to popular belief, only all that is tightly bound together. In particular, one does not have the reveal the bits of the "operating system" on which the free code runs. There is plenty of room to reveal some, but not all, and retain a competetive advantage.

Roku does not, for example, disclose how to defeat Macrovision or CSS. They can't for contractual reasons related to licencing these techologies. And they don't have to.

Of course, any tinkering voids the warranty. The point that you miss is that while .1% might tinker, 50, 70, or 99.9% of the user base might find the hack useful, and this increases the value of the base unit to them. Nothing stops Outlaw from taking a free hack, selling it at a price, to provide a hacker-provided feature with the benefit that the user does not void their warranty applying it (because Outlaw "approved" it). More likely, they'd include it for free in the next release of the firmware on the basis that the additional features will attract more customers.

The 990 has a USB port. Audio and (in maintenance mode) software can be downloaded to it. How hard would it be to send OSD information from a PC to the 990 via USB, such as Caller ID information gleaned from a modem when the phone rings? What about local weather updates? These are the kinds of possibilities that opening the unit up to hackers offers.

The device is huge (mostly because of the daughter board architecture). How hard would it be to include a mini-ITX board, and possibly hard drive, to turn it into an integrated MythTV box/pre/pro? That would be an ideal marriage of front end software and backend firmware/hardware, with the "restricted bits" (i.e. DD decoding, etc.) kept separate from the open bits? Heck, one could likely do it with little info about the 990 since it could all be done via IR control and hooking up a few signal lines internally instead of externally. (Outlaw: a daughter board accepting internal spdif and video connections would be nice!)


At this point, I'd simply like to see a top-level architectural diagram of the data and signal flow within the 990. It would clear up a lot of the errors and ambiguities in the manual.

I'm not suggesting that (to use the auto analogy) Ford provide engineering drawings for their engines. I'm just saying that good things can happen all around if the hood is not welded shut.

The people who hack consumer hardware know full well that they've voided their warranty.

I've been watching this thread with some interest for several days now. A few thoughts occur to me.

First, Outlaw does not pick up a blank piece of paper, create a design, and build the design by themselves. They use processors and other components that are designed and manufactured by other companies (Cirrus, Analog Devices, etc). They use processing protocols that are regulated by their originators (Dolby Labs, DTS). In some cases (such as the Model 990), they use a basic design that was developed by another company (Etronics, in the case of the 990) and then modify it to suit their needs (software changes, additional features such as DVI switching). At each stage in that, limitations are imposed on what they can reveal to the consumer and on how much they can differ from the mandated requirements - specifically the Dolby and DTS processing requirements. Outlaw has to adhere to agreements made with folks like Etronics and Dolby. We are not talking about whether or not the hood of our car is welded shut, since it is really not an appropriate parallel either. We've gotten a lot of good information already - the RS-232 information has been handed out freely, which is not always the case (that information is often restricted to custom installers because the manufacturers don't want to customer support calls associated with the average consumer trying to use it).

I do think that it might be useful to have a supplement to the manual, possibly as an accompanyment to whatever software update they are looking into, with some "advanced user" tidbits (signal path diagrams, bass management behavior description, and so forth). I don't think it is reasonable to ask them to open the books on the inner workings of the design to the point where we can start hacking the software to the degree that has been kicked around in this thread. Software is a huge part of how one of these units works, and opening it up to be "hacked" would be very close to the same thing as Ford handing us the design documents on their engine and powertrain. That's why you don't see Anthem or Sunfire or Lexicon letting us know how to make changes to the software on their processors. That's also why we don't have - and presumably won't have - the sort of architectural diagrams and software information on the 990.

gonk: Look at what Roku has done with the HD1000, a.k.a. Photobridge. They've opened it up quite a bit despite being constrained by the very types of license agreements you describe. I should know: I used to work for the company that provided them with the Xilleon X225 (or was it the 220?) on which the HD1000 is based, and was quite familiar with it's capabilties.

I do think that a basic architectural/block diagram of signal flow and processing would be a good start, together with the type of technical information like RS-232 command/status protocol. An appendix to the manual, perhaps available for a small fee, with a signed acknowledgement that Outlaw provides no guaranteed support for the information within, would be a great start.

For what it's worth, the RS-232 information is right here .

Yes, gonk, I know.

I do think that if an "advanced" or "service" manual were produced, though, it should be included there.

I have my front speakers set to "large" and my center choices are "none", "small", and "large".

The bottom line is that the benefits you're describing are easily outweighed by the risks. And the "manufacturers of consumer electronics" you've named are not the typical Japanese or US A/V companies making receivers/pre-pros. This is why none of them allow (let alone encourage) hacking of surround processing or signal routing in their products. And those are the type of products and functionality we've been discussing. Likewise why companies like Dolby and DTS are not accomodating hackers in their processing/decoding technologies.

As I said earlier, I'm all for added options (at least ones that are useful and makes sense). But the functionality you're wanting would require an actual mixer, which I still think is your best bet if you want to re-mix soundtracks the way you've described. There's nothing wrong with what you want to do, it's just that a home theatre surround processor is simply the wrong tool for the job.

This is why none of them allow (let alone encourage) hacking of surround processing or signal routing in their products.

A lot of that has to do with licensing and implementation. Usually the license forbids disclosure or modification of the algorithm, even though parts of it might be conveniently refactorable. I've often thought that the core of such algorithms remain controlled, with the bits around input and output more flexible, so, for example, a licencee can share common output level control code (and downmixing) among several decoders. But, even here, a lot can be done to open a unit up. Witness the Roku HD1000, and their requirements to not expose CSS or Macrovision control, etc.

There's nothing wrong with what you want to do, it's just that a home theatre surround processor is simply the wrong tool for the job.

If you consider the pre/pro a fixed piece of equipment, for a single purpose, I'd be inclined to agree. But, it is rapidly becoming a platform for software (and, in some cases, hardware) enhancements for new data and physical interconnect formats -- more like a general purpose computer than a specific purpose device. Particularly, when a manuacturer provides a software and/or hardware upgrade mechanism, a strong argument can be made that it is beneficial to the end user if third parties can use that mechanism to add after-market value -- rather like what Etronics did for Sherwood and Outlaw, but at a further downstream level (and not to the same degree of customization, obviously).

Other manufacturers are starting to do this (though, as you keep on harping on, not consumer A/V equipment manufacturers -- yet). Your objections to license restrictions and consumer electronics supposedly being immutable fall before the Roku HD1000 (really, the closest to a consumer A/V device that I can think of), and other, hackable consumer products - OFA remotes being another area, IIRC.

The response from the A/V hacking community has been to do what it can with what it has -- general purpose PCs, often violating matrixed audio encoding patents to decode DD and other formats in software, on fast processors. The only concession they get are A/V component-style cases, instead of the ubiquitous beige box for their HTPCs. A proper platform, with the licensed bits closed, and the right stuff done in hardware, but the rest open, would be killer.

Someone complained that the 990 does not switch HDMI, or transcode it to component analog video. I can't see how it would be impossible to develop an add-in card, to replace one of the existing ones, that does this, either by Outlaw, or a third-party.

We've gotten pretty far off on a tangent here, and I think it may be appropriate to pause and reconsider where we are.

First, I don't think the Roku products are a good benchmark for what we should expect from a surround processor's "customizability" - it is a niche product whose central information source is a network connection to a PC, whereas a surround processor like the 990 is a focal point for mass-market analog and digital audio and video signals. There is a very different host of issues and concerns to deal with.

Second, the Model 990 is a product that was designed in what we might call the "classical" sense for a modern surround sound processor. That design does include a method for updating firmware (in the 990's case, there are two parallel methods: USB and serial). It was never intended to easily support wholesale changes like add-on daughter boards for things such as the HDMI/DVI transcoding (and I think the real issue is that component isn't transcoded to DVI, not the other way around - although either proposition comes with a not-insignificant price tag attached). Can changes like that be made? Sure - but it would cost less to just replace the 990 with a new model that was designed from the ground up with those capabilities or to have a separate component with those features. I think there are some ideas being tossed out here that could be great to implement on a product, but that are physically or financially impractical for an existing product like the 990. It might be beneficial for Outlaw to start evaluating the options for the sort of "open platform" processor that Rene is suggesting, but tying that to the 990 seems painfully difficult if not impossible.

It might be beneficial for Outlaw to start evaluating the options for the sort of "open platform" processor that Rene is suggesting, but tying that to the 990 seems painfully difficult if not impossible.

I dunno if it's as impossible as you might think, gonk. After all, Etronics developed two somewhat different products on the same platform so there is some degree of modularity already present in the 990 design, (though balanced outs and DVI switching were clearly hacks).

The burning qustions in my mind are: How much? And, can some of that trickle down to the hacker?

I would not expect it to be a big priority for Outlaw, but I would expect it to be something they should think about.

Oh, and as for the HD1000, it was marketted as displaying high-res pictures. Hackers made it play back HD video in real-time, weather information, etc.

Rene:

At the end of the day, what you want is a computer, not a consumer electronics device. YOU seem to ignore the many reasons why, while there is merit to what you are saying, it simply does not fit the broader profile of the consumer electronics customer.

To say that the addition of the DVI jacks and balanced inputs to the 990 from the original platform are "hacks" is a dis-service, even if you take the definition of "hack" in the original more benign sense, rather than in the more modern "hackers are evil-doers" sense. I'd bet that to get those things correct the Outlaws had to do a considerable amount of testing, not only to make sure the individual modules worked properly, but that they integrated properly with the base platform AND that by adding them there was nothing done that might upset things such as Dolby or DTS certification, UL approval or FCC compliance for EMI/RFI.

A high-quality audio/video product is quite a bit different than an OSS computer, and you just don't "throw in" something such as HDMI switching. The compliance for that, alone, is both a bear and time consuming, the components are NOT cheap and if all of that weren't enough, the standards are changing under our feet.

I'm sure the Outlaws are thinking about all of this -- it is clear that the seem to read these posts -- but at the end of the day you are still left with the considerable difference between a card-cage/backplane type product that runs on OSS or some sort of RTOS and deals more with digital signals vs the very specific nature of purpose-designed products running tightly controlled software and having to operate in an area that has no tolerance for noise, bad grounding, bugs, etc.

You can talk about the Roku all you like, but a surround processor isn't a Roku. Same for TiVo. Sure, there are hacks for it, some of which are done with TiVo looking the other way, but many not. Can you hack into your TV? Your DVD player (unless it is in a computer, but then by definition it isn't a consumer DVD player since it uses software based decoding)? Can you hack into the micro that runs your microwave oven? Your 'fridge? You get the picture. The answer is no for a good reason.

Etronics made those changes in the factory - replacing space reserved for amps in the R-965 receiver with balanced outputs and DVI switching - and then did a lot of software revisions to support the DVI switching and the expanded bass management (and to clean up the interface in general). I'm not saying changes like that are impossible, but do you see Sherwood offering to retrofit P-965's with these features? Nope - because the costs involved in retrofitting those existing units would be large enough that nobody would want to do it, making it easier to either stay with what they have or have a separate product entirely (call it the theoretical P-975). Making additional changes to the 990 by adding entirely new boards is certainly feasible, but unless they had capability built in to easily accept "slide in" cards (think ISA/PCI/AGP slots on PC's) it is going to entail work that 99+% of 990 owners are not going to be able to do themselves. As for letting folks dig into the 990's software and "hack" away at it, it is an interesting idea in theory that might yield some interesting features - if Outlaw were able to get permission to somehow develop an SDK, it would be a groundbreaking move, but I would not be a bit surprised if Etronics either refused to allow it or attached a pretty nasty price tag to it. And even if they did come up with an SDK of some sort, how many of the 990 owners would be able to make use of it. I'm a mechanical engineer - I know my limits, and re-writing the code that runs my surround processor is way beyond those limits. There are likely to be more owners of something like the Roku (with a much lower price tag plus a network interface and the more nebulous feature set of a media server to offer a greater degree of "hacking") who can dig into some software and come up with something new. Heck, look at the Xbox - a large enough user base achieved a great deal of "hacked" functionality without any official support (and, in some cases, active opposition) from Microsoft. (Of course, that could serve to reinforce the theory that "hacking" a surround processor is improbably - the Xbox is drawn almost directly from off-the-shelf PC hardware and software, but the equally or more common PS2 and Gamecube have not experienced the same "hacking" because they are designed like most consumer electronics.) Would Outlaw be better served fighting for a way to provide some hugely expanded software access for the benefit of a couple of users, or should they focus on making improvements (such as speaker configuration settings, or finding a way to incorporate nifty new discrete commands via RS-232 or third-party universal remotes) that benefit all users? I can understand your interest in the former, but I think the overall customer base will benefit much more from the latter.

Well said, Gonk!

I see this thread as:
1. Renee wants to Hack the 990, but wants the Outlaws to provided him with info to make his hack easy. No respectable Hacker asks for help!

2. If he really want to hack the 990, get a good axe and hack the hell out of HIS 990, and get off the Outlaw's case!

Facinating discussion...I for one would like to have the ability to variably downnmix C info to L/R from a discrete source; whether the 990 has mixing capability I could not say, luckily the outlaws know the answer!
My maganpan 20 ribbons L/R far outpurform the maggie CC2 Quasiribbon (though that limitation is made less by using a ICBM in recombine to remix 200hz and below to the bass panels of the biamped mains.) Of particular use would be when guests arrive for the film, I would like to have a macro to give, say, 90% intact center, and for my wife and I only, I'd like just, say, 20%; the rest mono to the mains.
I am thrilled to see the post from Scott stating that they are working on a software update and are reviewing issues talked about here. My hat is tipped to them for that...as I have written before, I am REALLY disappointed with the display vidio out and panel info (no signal type info such as PCM 48k/44.1, or DD 2.0/5.1, no current mode display, this makes it difficult to choose what mode is appropiate. I had this with the 950!). This is such a important issue for me due to my not having a way to see the 990 from listening position, and rely instead on a remote dedicated CRT, though walking behind speakers to look at the panel doesn't help either as no data type info is there either. I had been so upset about this that I considered putting back and returning the 990 during my 30 days. Thing is, it DOES sound great; better than the 950 for movies, really good for PCM upsample. My early concerns about DD sounding poor appear to be related to incorrect spaeaker distance settings due to my using a outboard digital xover on the mains...still no time to evaluate DTS (new baby and all)

Indeed.

I don't understand why some people, when presented with the limits of what is possible given application of a particular philosophy to product design (open access to various implementation details), reject the philosophy soley on the basis that some extremes cases of its application may not be economically practical or legally possible.

I continue to believe that (a) increased openness about the 990 design and implementation and greater access to internal processing options benefits Outlaw and it's more progressive customers; (b) this can be done without great cost to Outlaw in the simplest of cases (orthogonal feature applicability).

The biggest argument against any such opening up is "We don't have the time to implement that now," which would be perfectly reasonable. But, some indication of what might be possible in the future, at least an acknowledgement of enough of the internal architecture, would be welcome.

That's because "some people" see more practical alternatives.

There's nothing to stop a hammer manufacturer from putting a philip-head screwdriver at the base of a hammer so that it can serve double-duty and do the work of two tools. However, you don't see any hammers like this because screwdrivers already exist and are a more practical tool for that application.

Similarly, the type of functionality that you want (which, let's face it, is the ability to remix a movie soundtrack), is more practically done with an inexpensive mixing console. Not being "economically practical or legally possible" are valid reasons for not squeezing that functionality into home theatre pre-amp/decoders.

This isn't something specific to the 990. There isn't a single HT pre-pro that has the sort of re-mix capability that you want. And that's not based on some rejection of a "particular philosophy", but just a matter of practicality.

Similarly, the type of functionality that you want (which, let's face it, is the ability to remix a movie soundtrack), is more practically done with an inexpensive mixing console.

And what is a mixing console but software, in the digital domain? Why should I have to buy an outboard unit, that works in the analog domain, when all the hooks for a digital mixer are already there?

The point is that I view the 990 as being built up of several hardware and software modules and I'd like greater control in how those modules are wired up, so their facilities are fully utilized. The supplied operation should be a default, or manufacturer-selected "product" made upon this platform. But, it is frustrating when the platform is not exposed as part of the product.

This philosophy would also permit those who do not like the UI to write their own, if so inclined, and not have to accept Outlaw's view of what is the most user-friendly.

Many of the choices made in developing a product on a platform are arbitrary and there is no guarantee that the manufacturer made the right decisions regarding how to put the bits together. This does not mean the entire design and architecture has to be exposed, but a few hooks would increase tha applicability of the platform greatly.

Not being "economically practical or legally possible" are valid reasons for not squeezing that functionality into home theatre pre-amp/decoders.

Except that applies to extremes of the philosophy of open design, and not to all cases of exposure. It would be folly for Outlaw to make Macrovision defeating configurable, for example. But, there is much they can do without such questionable bits.

This isn't something specific to the 990. There isn't a single HT pre-pro that has the sort of re-mix capability that you want. And that's not based on some rejection of a "particular philosophy", but just a matter of practicality.

Take a look at some of the image processing capabilities, particularly deinterlacing choices in Linux PC-based HTPCs. There are cases where the deinterlacing algorithm is plugable. DD decoding is also often available, making it a pre/pro in my book, though the legality of doing that is questionable. Finally, the difficulties of doing all this in software and not DSP firmware, are that a very powerful processor is required, which means a noisy fan, and all that entails.

No doubt the 990 is based on some type of platform. Exposing more of that platform would go a long way to understanding some of the more odd parts of the 990's operation and create the possibility for community-supplied enhancements, or if the platform was simply documented, but not made available at a lower level, informed suggestions regarding same.

Why should I have to buy PC when there's a computer built into my microwave oven? Even in this age of software based devices, there are still different tools for different uses. All the hooks for a mixer are not in the 990, despite what you may want to believe. I suppose some one could design a HT pre-pro that has the functionality of a studio mixing console built into it, but the demand for such functionality is so non-existant that no one has done it. Zero, zip, nada. And is this the product model that you're holding the 990 up against for comparison? A noisy fan and questionable legality? Honestly, rather than have a HT pre-pro with those problems, you really would be better off with a mixing console. It's what recording engineers use when mixing (or re-mixing) movie soundtracks, so it is the right tool for what you want to do.

Duplicate post.