I know this subject has been discussed before in this link http://ubb.outlawaudio.com/ubb/Forum15/HTML/000816.html but I am still having a problem setting correctly. While redoing some of the equipment I began to run through the normal setup items with the SPL meter and everything is going fine until I get to setting LFE phase using the Chesky disk. I believe there is something odd with the LFE phase tests on this disk. I am having similar problems to Kevin C.Brown in that no matter wat I do the out of phase signal is always louder while using the 6 analog inputs. I now have the system setup so that only the LFE is driving the sub amp and switching the phase makes a slight difference in sound but it doesnt change the fact that the out of phase signal is louder.
While trying to figure this out I wanted to see if the signal being sent to the amp is equal for both the in and out of phase signals. If I measure the voltage coming out of th 950 at the LFE jack the mV reading is a little more than double for the "out of phase" sinal compared to when the signal is "in phase". I don't know if this is a proper way to test for this and that is my reason for asking some of you local electronic experts. It seems to me that the ouput from the 950 (or the DVD player) should be the same reading regardless of it's phase. I can naturally increase or decrease this signal with the volume on the 950 but the variation always seems the same. I tested phase signals using another disk (Avia) and I don't get the variation in the voltage signal.
I guess my question is that if for some reason the "out of phase" signal being produced using the Chesky disk is higher than the "in phase" signal the amp will play louder, would the use of the SPL meter to check phase be useless?

Keta,

The first thing I'm curious about, is how you have your system configured to send only the LFE to the sub amp when in 6 CH BYPASS?

The second issue regarding phase alignment between your mains and sub is that, unless the mains and the sub are exactly the same distance to your meter, you're not likely to ever have the phase correct if you only have a normal/reverse phase switch as your tweak.

There is definitely something at play when switching from the digital filters of the 950 to the analog filters. Exactly what the answer is was never arrived at, at least to my satisfaction.

I personally think that the problem arises from the way digital BM works, creation of a duplicate signal for each channel, 1 that's HP filtered and the duplicate that's LP filtered (selectable triple crossover), volume adjusted and sent to the summing block to be combined with the LFE signal, which has a global, 120 Hz LP filter applied.

Analog BM is a simpler 80 Hz HP/80 Hz LP Linkwitz/Riley active crossover.

Other issues include whether or not your player applies a global LP filter to the LFE signal in the digital output vs. no filter on the analog LFE output.

The fact that some people experience the phase shift when switching from digital BM to analog BM and some do not, indicates that placement distance differences and/or player/950 cascading filters probably have the most to do with the answer, because there's no way I believe that some 950s have properly wired analog crossovers and some do not.

As far as the setup discs that are currently available for multichannel audio systems, I'm not a fan of any of them.

I just use a SACD MC disc that has good LFE content and repeat a track that has a bass line intro and play, meter, reset and pause, adjust phase and repeat until the reading is highest, with the SPL meter in my listening position.

BTW, I don't see a difference when switching back and forth because I keep my 950 in 6 CH BYPASS mode all the time.

Bosso thanks for the response. I will try and answer some of your questions.


Denon sub out --> 950 sub in --> dedeicated sub controller/amp --> speaker



The subs(2) are directy beside the mains. Can't get much closer together and they are the same distanse from the meter. The mains are bi-amped using the Main L/R but were turned off for my testing.



I was only using the analog connections.



Whatever the 950 uses through it's sub out, the the bass management set to off.

I have all the filters disabled and am only using the analog connections. I am not seeing the difference when switching between bypass and digital (although I'm sure I would) because I havn't left the 6 channel bypass yet. The Chesky disk is in DVD-A and that is all that I have used to setup with.

While typing this I went and tried a few other things. I let the Chesky disk repeat it's 60Hz phase test with the SPL meter reading 80dB for "in phase" and 90dB for "out of phase". Switch polarity on the sub and nothing changes. Remove the LFE cable from the DVD player and the SPL readings are 80dB for both phases. Switch sub polarity and nothing changes. I wouldn't expect the sub polarity switch to change anything since during this setup I'm not trying to match the phase of the sub to anything.

So it appears that the 950 sums L/R bass and passes it to the Sub output(double bass syndrome) along with the bass being fed from the DVD players LFE output. But it also appears there is no increase in SPL if the signals being fed are in phase. Does that make any sense?

Anybody have a work around that I might try or should I just do as bosso says and use music. bosso give me a musical suggestion in DVD-A if you can.
Thanks

The chesky disk also has a DD 5.1 phase check. Just set your denon to DVD-Video (in my 3800 that's a option in the set-up menu under the "Etc." tab) and the chesky disc will fire up in DD instead of dvd-a.

Thanks jgubman. I just switched over and I'll run the checks in the morning.

Decided to try the DD track a try and it appears to work fine with the digital input but wrong using the 6 channel input. I had to make some adjustments to the 950's crossover points while using the digital input. I had the fronts set to Large and the sub On and I assumed nothing was taken from the fronts and sent to the subs but alas I was wrong. Not only does it forward information but it is dependent on the crossover point. When i switched to the 6 channel input still using the DD track the problem appears to be the same as using the 6 channel inputs with the DVD-A.

Keta,

are you saying that w/ the speakers set to Large and Sub on in the digital mode you still get summed bass sent to the subs?

That can't be correct, can it?

I agree that w/ the analog outputs, all kind of weird stuff is happening to the bass. I've recently purchased truly full range front speakers (VMPS RM-40s, flat to 24Hz) and the Outlaw's flawed analog bass management is getting really frustrating. There seems to be NO way for me to get the sub-80Hz frequencies to the fronts w/o also going to the subwoofers.

Here's something even more interesting. I have the Lexicon MC-8 now which doesn't have BM on the 5.1 inputs. If I adjust phase correctly using a digital signal to the pre/pro, and then compare to the analog DD signal out of the player, I am OK. (But there are small differences in phase.) But when I check with DVD-A analog, out of phase. I tried both with and w/o BM enabled in the player. Now, I am convinced the player is doing something funky.

One thing I want to check but haven't had time, is just try this using the front L & R speakers. Wierd, huh?

That is exactly what is happening. This is what I'm doing when this happens. Using the Chesky disk, DD setup, track 23 - 60Hz phase test which is a test for setting the phase between the mains and sub. My mains are biamplified and I have the lower bass section of the mains turned off so the only thing reproducing the 60Hz tone is the sub. The sub is being fed it's signal with the LFE output from the 950. I believe by just having the sub reproducing the 60Hz, phase doesn't matter since the sub is acting alone.

DVD playing track 23 repeating, no bass management in the player.

950 set to optiacal input, volume set so RS meter reads 80dB, all speakers set to LARGE, sub ON, crossovers set at 150Hz.

While playing the tone I went to the speaker setup in the 950 and took these readings from the RS meter while lowering the crossover setting for the front speakers:

Crossover setting -------RS meter (dB)
150Hz -------------------80
120Hz -------------------80
100Hz -------------------79
80Hz -------------------78
60Hz -------------------75
40Hz -------------------65

My conclusion is that you do get summed bass to the sub in digital mode and it is crossed over at the front speaker setting. Another odd thing is if you turn the sub setting to OFF it forces the the bass signal to the surrounds as well as the fronts but not the center. It only forces to the surrounds if they are set to large and none of the crossover points change the output. Strange?

[This message has been edited by Keta (edited December 09, 2003).]

Keta,

In one of your posts, you said that you have the mains bi-amped, but shut off for the test.

In the following post, you said that the mains were on for the test.

What are you using for mains and what is their published response (+/-3dB)?

Also, what 'dedicated sub controller' are you using?

Jgubman,

The 950's analog BM is NOT flawed. It works exactly as it was designed. The design is for the switch to be in the 'on' position, in which case, it works as accurately as any active crossover I've ever owned...at any price.

If you insist on switching it 'off', make sure that you are using 5 identical, full range sats, perfectly equidistant from the LP (per ITU standard, which see).

Otherwise, lesser surround and center speakers WILL suffer damage at ref level with many hi-res discs.

If you don't have full range all around, but you still want the switch 'off', then bi-amp your mains and adjust the 950's SW trim until you have a flat response. You'll have to run sine wave sweeps and use a correction chart to draw a graph of your in-room response, but if you do, then you'll see that there is not only no flaw, you will have a better shot at a flat curve result with the analog BM as is.

You can also run the cable from your player's analog SW output directly to your subs instead of the 950's analog SW input.

This will send LFE only to your subs and full range without LFE (since there is now no LFE input into the 950, there will be none in the mains) to your sats.

This is a very simple work around that requires nothing more than redirection of the same cable. The tradeoff is that you'll have to adjust the LFE level manually. The plus side is that you'll be able to do that independent of the sats bass level, to taste, and you'll now know when there is LFE signal on any given source, where otherwise, you have no idea.

BUT...the phase alignment of these 4 subwoofers is crucial to proper playback of any MC source, regardless of the preamp's configuration menu.

When I say equidistant, I mean get out your ruler and place the subs equidistant with the mains to the LP. Measure from the center of the cone to the meter's mic.

This should be done before any testing or EQ is applied.

I'm not into DVD-A. I prefer SACD, so I would have to say, given my limited knowledge of DVD-A titles and their LFE content, that Steely Dan's 'Two Against Nature', Shame About Me or Cousin Dupree are good tracks to do a bass phase test.

Play the beginning of the track, with 1 sub shut off, the speakers placed properly and the SPL meter set up at the LP and note the reading. Reset the track and pause. Change the phase conrol to reverse and repeat. Use the setting that reads highest on the meter then repeat the procedure adjusting the phase control about 1/10th increments from 0 to 180 degrees each time.

Then, leaving that sub on, turn the other sub on and repeat the procedure.

You'll have to note the results and repeat the test for digital mode. If the results are different, you'll have to switch back and forth for each mode before you play.

Sounds like a PITA, but it really isn't when you know you're hearing your system at it's best for any source you play.

Nht 2.5i's, 29Hz-25KHz +/- 3dB manufacturer spec. The speakers are biamped with NHT SA-2 amps which are fed with the front L/R signal and passed on to two channels of the 770 to power the upper portion of the mains. When running these tests I just turned down the amp feeding the lower section of the mains so that only the subs were playing. I did this to only hear the sub (I unplugged the other) while being fed the 60Hz tone in and out of phase. My thought (could be flawed so let me know if it is) was that a single speaker playing a single tone won't sound any different being in or out of phase since it's really not in or out of phase with anything else, and what I was noticing was the drastic change in SPL while listening to that one sub being fed a single frequency with the only change being phase. This only happens using the 6 channel input. The whole thing may mean nothing I was just looking for input from others on what they felt.



They are a pair of NHT SubTwoi's with a SubTwoi controller which is needed since the subs only have an RCA input to the built in amp. All control ie: phase HP, LP, LFE gain, volume and such are handled by this controller. Right now the controller is only acting as a volume control since all filters are set to bypass and it's only connected to the sub out from the 950. This link will give you a quick look. http://www.nhthifi.com/scripts/nhttech.c...ated=1062965377

I will try your suggestion with running the LFE directly from the DVD player and see how that works.

im not sure exactly what you are trying to correct or figure out. a lot of subs have two phase adjustments (in/out), so one would play a sample with the phase being in and then out and see what they prefer to find the proper phase adjustment. the typical setup would have the phase in the position that produces a less boomy sound.

ok, I agree the crossover slope in not flawed.

What is flawed is having NO WAY to aviod getting 80Hz and below frequencies summed and sent the the subwoofer. Why can't I get the analog xo out of the way? You're saying that eastech designed the analog BM to ALWAYS send summed info to the sub, regardless of what's happening w/ the info sent to the other speakers? Ok, if that's the case, then the design isn't flawed, but whoever spec'd it that way was flawed. What's the point of having a switch if it's always supposed to be in the "On" position?

Regardless, I think the Outlaw is a great piece at this price point. I've been getting around the analog BM woes by setting all to Large and using an ICBM btwn my amp and preamp. In the DVD-A player's menu, I've set the sub to off. When I want to listen to a DVD-A, I set the outlaw's sub to off and let the ICBM do the filtering. Only problem is remembering to turn the sub back on when I'm done w/ the DVD-A.

I am a little disappointed to hear that the digital XO is now suspect as well.

I'm really looking forward to my next processor not having these quirks.

curegeorg I'm just trying to figure out why I can't properly set the phase of my sub using the 6 channel inputs on the 950. Just imagine my the entire consisting of three components.
1. DVD-A player
2. Outlaw 950 connected to the DVD-A via 6 analog cables.
3. A single powered sub connected to the 950 using the 950's sub out. No other speakers.

In this phantom system if you were to play a 60Hz test tone that alternated every five seconds from "in phase" to "out of phase" the volume of that single sub will vary +/- 10dB. That should not be the case and I'm looking to see if anyone has any insight into why this is. In the above system if you did the same test tones using a digital connection you would not see the volume fluctuation. I'm trying to understand it so hopefully I can work around it. The reason this seems important to me is that if one speaker varies it's volume by 10dB based on the phase of the signal then it will be difficult to properly adjust it when you try and blend in the remaining speakers. Bosso may have the easiest workaround but I havn't tried yet.

OK, I just repeated your tests, using the Chesky disc:

In-phase/out-of-phase, results were correct both in DD and in 6 CH BYPASS (without changing anything in my system).

I then shut all my monoblock amps off to the sats, set all speakers to 'large' and sub to 'on'.

Using the in phase-out of phase test #23, 60 Hz, in DD mode (BTW, the readings were identical for both in phase and out of phase, as you expected, with only the sub playing).

I got basically the same results as your test. This does NOT mean that summed bass is getting to your sub when all speakers are set to 'large' and sub 'on'. It means that the 950's x-over is working properly.

A Linkwitz/Riley 24 dB/octave crossover, which is what the BM consists of in the 950, causes the signal of both the HP filter and the LP filter to be attenuated 6 dB at crossover so that when the 2 signals sum, they are at unity.

When you play a 60 Hz tone and set the crossover to 40 Hz, the signal from only the LP should be down approx. 16 dB.

When you set the x-over at 60 Hz, it should be down 6 dB, as explained above.

When you set the x-over at 80 Hz, it should be down approx 3 dB.

When you set the x-over at 100 Hz, or higher, it no longer attenuates a 60 Hz tone, so it should play at full volume, which, in your case, is 6 dB higher than the reading you get with the x-over set at 60 Hz, playing a 60 Hz tone.

Look at your results and you'll see that the crossover is pretty deadly accurate, accounting for room interaction at 60 Hz at your LP.

What this test DOES prove, is that the so-called 120 Hz global LP filter on the LFE signal is governed by the crossover, and, as such, is NOT global.

It's moot to me, as my LFE is discrete and free of the 950's influence anyway, but Scott assured me in an e-mail that I was mistaken and offered to bench test my 950 to prove it.

If the LFE filter was a global 120 Hz, ALL the readings would be the same in this test.

Sorry for the side issue, and leaving it aside, I hope the explanation above helps you to understand your test results.

As far as the analog BM switch goes, it does NOT read 'in/out' (as in 'bypass'), it does NOT read 'on/on'...it reads 'on/off'. That refers to the sats as 'large' or 'small' and nothing more. The specific function of this switch is more than clearly explained in the manual on page 9.

You can disagree with the nomenclature of the switch for whatever reason, but that does not make the 'on/off' labeling by Outlaw a mistake.

As I said above and many times before...experiment with the switch vs say, a uni player's DVD-A/SACD BM and see if you don't get a better curve with the 950. This is a whole other story for another time, which I will be more than happy to aid and assist anyone who would like to understand Outlaw's engineering of this aspect of the 950 with.

Bossobass I want to thank you for taking the time to run the tests and give an explanation. I'll give the "direct DVD to sub" a try and see how it works. Let us know if you discuss the global crossover issue with Scott and what Outlaws opinion is. For anyone else reading I hope no one got the impression that I was some how disappointed with how my setup was sounding wth the 950. I was just running through some calibrations and this issue just got me spinning my wheels.

I'm always glad to see someone who is willing to tear into his system with meters and tones and get to the bottom of how it all works.

This is how we all learn to optimize our setups, which is always rewarding, and I ALWAYS come away with new info.

I repeated your tests because you so clearly explained the tests you ran...made it easy!

Roger Dressler of Dolby recently wrote about low pass filters and phase shift in http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=332595&perpage=20&pagenumber=4 with regard to Center, Left and Right speakers, specifically:

I don't know if the 950 uses 2nd or 4th order filters to redirect, but apparently, in some LFE cases, it matters.

Best,

Will