Signal Lock

Well, it sounds like the hissing issue has finally been resolved. Now, barring any potential issues with the center channel output, my only other concern was the length of time it takes the 950 to lock on to certain digital signals and or the temporary loss of signal lock during certain operations -- such as changing DBS channels. Has anyone found this issue to be particularly annoying? Does it ever occur during DVD playback? How does the signal acquisition time compare with common AV receivers?

The 950 takes a couple seconds for the signal to make it's way through the various DSP/switching ICs. My Sony pre/pro takes about the same amount of time. It's not really bothersome, but I wish it were a shorter time for the switching to take place.

Within track 8 of Pearl Jam's Riot Act, and in between track 8 and 9, the 950 loses, and then has to re-acquire the signal.

It's a good test, because two different 950's have done it in my system, with 2 different (Pioneer) DVD players.

*This*, I can live with (as compared to hiss).

Maybe the next thing that gets "fixed"? But I reckon we won't get to swap units out for this one...

Out of maybe 20 DVDs and 50 CDs I've put through the 950, only this one and "Sharks" by UFO has exhibited the problem. (Well, losing the signal within a CD or DVD.)

Kevin:

Those particular CDs might have been mastered incorrectly, with the writing laser turned off between those tracks. This is the familiar "disc at once" option being turned off when writing CDs. Mistakes can happen, even with 'professionals'

[This message has been edited by soundhound (edited January 03, 2003).]

SH- That's why I wasn't *that* hyper about the UFO disc (Mike Varney records or something in LA). But the Pearl Jam is a major release. Plus, it loses the signal *in* track 8. Don't think that's the mastering.

If ever I get motivated to hook my Sony pre/pro back up, I'll let everyone know if that loses the signal. But in over 4 yrs with many many CDs, never happened once with that one.

Could it be related to the CD player tripping up on some form of copy protection?


[This message has been edited by dmeister (edited January 03, 2003).]

That seems kind of surprising to me, given how fast the processor should be. Speaking of which, what kind of processing power does the 950 employ? Many manufacturers love to tout their various two or three 32-bit processors, but I couldn't find much information from Outlaw.

The processor might have to load firmware to accommodate a switch to another surround format, or possibly it is just an active mute as the inputs are switched. Only making somewhat educated guesses...

I don't believe that Pearl Jam disc has any copy protection. I know that the UFO disc doesn't.

My theory is that at least for the Pearl Jam examples, is that there is a "timeout" for the 950 to lose the signal. If the time out was lengenthed slightly, should take care of the problem. (More time allowed when a signal isn't present before the 950 loses the lock in the 1st place.) But, might make *switching* locks from one source to another slower.

So with the hiss solved, the next thing to tackle is the delay. The folks over at Sunfire had the same problem and were able to fix it with a flash upgrade. Any chance that is coming down the pike for the 950? I do find the problem particularly annoying when using the FF function in Tivo (which turns off the digitial output temporarily when skipping forward, back or pausing). Also, (1) any fixes for the pop caused by switching the ditigal sources (again, problem when using Tivo) and (2) any fix allowing for the use of Large front speakers without causing the sub to disable?

Sadly the 950 isn't flashable. I suspect it would at least require some quality time with a chip extractor and inserter, and that's assuming the ROM is socketed.

I've poked around inside the 950 quite a bit, and there doesn't appear to be anything that is not surface mount, and no EPROMs or such that can be easily swapped.

Hmmm. Some embedded CPUs have onboard nvflash, maybe that's where the firmware is? It has to be somewhere....

I suspect it's on the circuit board used for the front controls/display, but I didn't take it that far apart to verify. Lots of itsy-bitsy parts in there, though.

I believe that the AT clone's tech sheet says that the design uses an EPROM chip...

I'm sure it does; the 950 too - I don't think it would be any more programmable in the field than the 950 however.

Found another occurrance of loss of signal lock within a CD.

In between tracks 5 and 6 on Sabbath's Never Say Die. The Castle Communications remaster from England.

Kevin:

One thing you might try that could possibly make a CD that would not skip between tracks: Rip the CD onto your computer. Then burn a copy of the CD, setting the time between tracks to zero, and setting the software for "disc at once" which does not turn the laser off between tracks. This might yield a CD that you can play without the loss of lock between those tracks. If this cures the problem, it will tell you the probable cause of the original CD skipping.

IIRC the issue with timing is also a direct function of the source product's programming of how it handles the signal.

i.e. not all DVD/CD players manipulate the digital signal the same way. They vary in their timings and muting of signals during various functions such as FF, rew, skip, etc.

SO, the 950 might react quite differently depending on which brand of CD or DVD player yoy are using as a sourve.

Just an FYI.

I've had Pioneer DVD players for years. Sometimes had initial lock delays with the Sony TA-E9000ES pre/pro, but NEVER in the middle of a CD.

With the 950? I do.

And even if it is how a CD is mastered, that still doesn't explain the 950 losing the lock in the middle of that track on Pearl Jam's Riot Act.

If the 950 loses lock at the exact same place on the CD every time, there has to be something at that point causing the problem. If it is between tracks, my guess would be that the cutting laser was turned off between those tracks, and the 950 can't handle the temporary loss of signal.

SH: That might *explain* it, but doesn't make it acceptable, especially when, for example my TA-E9000ES doesn't lose the lock...

I say, a continuous improvement activity for the Outlaws...

I never said it was acceptable - But if this is the cause, you can burn yourself a copy CD and at least be able to play it without the dropouts.

Ooooh, a data point:

In every case of a "signal lock drop" I've had, if I go back and play the specific area again, *but only start my DVD player within about 5 - 10s of the offending portion*, no signal drop. If I go back to about 60s before the dropped part, bingo, dropped again (very repeatable). So if it was a mastering problem, seems to me it should be dropped no matter how far in advance of the "bad" part I started my player?

I presume that in the 5-10s case, the 950 is still in "looking for a signal" mode, so even if there's too much of a gap, it maintains the lock. But 60s in advance, the 950 goes back to "normal lock" mode, and hence the dropped lock. ??

It does sound like a time constant type of thing with the lock of the signal.

By the way, I'm dying to know: if you burn a copy CD, does the problem go away? I don't have any offending CDs, or I would perform the experiment myself.

Does the Rotel 1066 suffer from any of these issues?

SH: oops, OK, I'll try that... (Burn all at once and not track by track so the laser doesn't shut off...)

I was wondering, does the signal lock problem on occur on the digital coax input or on the optical input or both?

I've been meaning to look at this too. I've had the problem on both 950"s I've had, but I've only ever used the coax input...

Data point:

Pioneer DV-05, 45a, 47ai through the coax input loses lock on the Pearl Jam CD in the cases above.

HHB 830 CD Recorder through the optical input ... also loses the lock. Whatever it is, is deeper in the 950 than just the input type.

Thanks Kevin. I was hoping it would occur in one or the other and not both.

Found another CD that has signal lock issues with the 950. Smashing Pumpkins Earphoria. The 950 loses lock in between some of the tracks.

Another one: The Cure's Bloodflowers. At least in between tracks 4 and 5.

I seem to either be noticing this more recently, but I hope it's not a case where it's getting worse.

Every type of digital audio signals has a unique pattern (Dolby Digital AC-3, Dolby Digital EX, DTS, DTS-ES Matrix 6.1, DTS-ES Discrete 6.1, DTS 96/24, HDCD, MPEG-1, Layer III, MPEG Multichannel, Linear PCM, and yes even digital silence (all 1's or all 0's).

With this in mind, the DSP is responsible for reporting to the host microcontroller (Toshiba 100-pin part located on the main board) what "pattern" it currently is seeing.

If it sees AC-3 (Dolby Digital), then it tells the host controller, "I have autodetected a Dolby Digital signal, please load the Dolby Digital code (or Dolby Digital EX code or Dolby Digital 2/0 + Pro Logic II code or Dolby Digital + Cirrus Extra Surround code) - depending on what processing mode the listener prefers"...the controller does just this.

So, imagine if you will that a Linear PCM stream contained a small segment of data that "looked" identical to that of AC-3, DTS or some other type of compressed data or digital silence...

The DSP would originally report that it was processing Linear PCM data...but then, all of a sudden, the stream emulates that of a compressed stream...so the DSP reports that the stream type has changed to the host controller and automatically mutes the outputs... the host controller, then starts to load the proper DSP code to decode this new type of stream... but just as it is finished, the DSP then reports to the host... now the stream is Linear PCM again... please load the preferred PCM processing code... this would sound to the listener as a "drop in audio" or a brief muting of sound, when there should not have been one.

The "initial" signal lock time, has more to do with the S/PDIF receiver. The 950 uses the world-standard Cirrus Logic "Crystal-brand" CS8415A, so lock time for almost any bi-phase mark encoded signal (regardless of the physical connection being optical or coaxial) should be around .5 to 2 seconds, depending on the quality of the biphase mark encoded signal being transmitted from the source, and the sampling frequency.

Keep in mind that a S/PDIF receiver only converts biphase mark encoded data to I2S digital audio format, which is fed to the DSP. If the S/PDIF transmitter in the source device (CD player, DVD player, STB, DAT machine, etc.) stops sending a valid biphase mark encoded signal (which can happen during a track change or station change or FF or RW, depending on the manufacturer)

The DSP inside the 950 is a Cirrus Logic "Crystal-brand" CS49326 (www.cirrus.com) which is a dual-engine 24-bit, fixed-point Audio DSP. It is the worlds most commonly used Audio DSP in most of the AVRs and Processors.

Try disabling the "autodetect" feature and select PCM only for these "troublesome" CDs see if an audio dropout still occurs... surely there was some reason why this ability is included in the 950.

The Oracle has spoken...



[This message has been edited by Scott (edited February 05, 2003).]

Hmmmm.... Maybe it's just Kevin's taste in music - none of my CDs exhibt this behavior

I used to know a guy named Mark, who was bi-polar - is this the same thing?


[This message has been edited by soundhound (edited February 04, 2003).]

Whoa. Hello Oracle....I love this place, so many things to think about.

PS. use Toslink currently no dropouts here notated to date.

[This message has been edited by Smart Little Lena (edited February 04, 2003).]

TO- Something to try. I suppose then that when I play a DVD, I have to change the setting, but will be interesting to check.

SLL: I have the problem with Toslink too, even with a different player. My red dot (equivalent) did it as well as this blue dot (equivalent).

Yeah, I was just thinking that as I come across CDs that do this, everyone gets a peak into what I'm listening to...

True, or you could do this -- configure an "extra" input (I'm using AUX2 at the moment) to use the DVD player's digital input. Then you can set it up for CD playback only (stereo or PLII as you prefer, disable autodetect). Set up a macro to change to that input (saves having to cover the front of the remote to switch back to DVD), and you are good to go without messing with the DVD input's settings.

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gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

OK, if I do "dedicate" the digital input, as expected (if you think about it for 2 sec), it does eliminate the 950 losing the lock.

Gonk- I had thought about your way too, but not long enough. I would use the CD input for coax1/PCM say, and then DVD for coax1/auto. But I already have a CD burner hooked up into the CD input. But now that you mentioned it: aux... Cool.

Just curious, but *no one* else out there has this problem? I haven't seen anyone else post about losing the lock *within* a CD, just say switching between cable or DSS boxes an stuff. Even if it is something unique to the player I have, I know there are other people out there with the Pioneer DV-45a/47ai / 950 combo. (My HHB burner also exhibits this, but I believe that it has a substantial % of Pioneer component inside.)

Well, if one has to snoop the data stream to sniff out what sort of data is being transmitted the protocol is pretty poorly thought out. Working with idiotic protocols sucks; If this is really the case I feel for the poor slob that had to work on it - I always walk away from that sort of thing feeling like I should wash my hands or something.

-- Yeah, I was oddly (and disproportionately) pleased with myself that evening...



Not me. Sorry. I don't have any of the specific titles you've mentioned, but none of the discs I've run through the 950 have exhibited this behavior. My second 950 was, I believe, set to PCM on the CD input last summer, but the red and blue dot units have been left on autodetect.

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gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

Gonk- I have to admit, I just re-set up how the remote controls the 950, and I like it!

DVD => coax1/auto (DD/DTS, etc)
CD => coax1/PCM
Aux1 => opt/PCM (CD burner)
Aux2 => coax2/PCM (DAT deck)

So, I guess I can still wish the signal lock issue wasn't there, but I guess with this setup, I won't have the problem anymore either.


[This message has been edited by Kevin C Brown (edited February 06, 2003).]

When you guys are talking about setting the digital cd input to "PCM", I assume you mean setting it to stereo, as I see no PCM option in the setup menu.

We're referring to the option to override the "autodetect" mode of the digital input and "lock" it to one format (page 31 of the manual, "Surround Data Format Lock") -- the options are "auto" (the default), Dolby D, DTS, or PCM.

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gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

Kevin,
First I want to say that you have awesome taste in music. Not too many are into UFO and Black Sabbath these days. I just went to the Rush 30th anniversery tour. It was great. Just ordered tickets to the Queensryche show in the Moore theater. They are doing Operation Mindcrime in its entirety.

I have the Pioneer 47ai and have dropouts while playing DVDs. It's pretty frustrating. I'll have to try locking the source after I find the manual. Just moved to a new house.

I wonder if there is something funky with the Pioneer DVD players?

Allen