DaleB:

What player do you use?

Apparently, it must do digital BM in DVD-A/SACD formats, in which case, to which 'large' speakers does your player route the LFE signal?

The 950 filters the low freqs (LFE included) and outputs a single bass signal to the SW output.

What happens to the center channel signal (you say it's input into the 950, but you run a 4 channel+sub setup)?

Sorry for the Q's, I'm just curious

No problem.
I am running a Panasonic CP-72. The configuration in the player is all 5 (sorry I did say 4) set for large. So all info including LFE is sent through those channels.
I 'eliminate' the sub out. (In the player menu as well as physically do not connect a Sub input to the 950 from the player).
So now, the crossover in the 950 (switch ON) splits at 80 Hz, anything lower rolling off to the 950 sub output. Anything higher, rolling up to the 5 satellites.
And they are satellites, this is an M&K 750 THX system. Sub is self-powered.
Back to my orignial question, is the phase reversal happening within the 950 Bass Management OUTPUT circuitry, or only on the BM input circuitry? Breaking it down futher, visualize a signal and ground at the sub input to the BM and a signal and ground to the Sub output. Where is the phase reversal actually happening? I am probably over-simplifying the anomaly.

I don't understand your question.

If you set the phase to be correct between the mains and sub using the digital crossover in the 950, via the digital inputs, more than likely, the phase between the mains and the sub will be out of phase if you use the 5.1 analog inputs. The difference in phase is probably being introduced by either the digital crossover circuitry itself, or the 80 Hz analog crossover.

I jumped into this subject with both feet without fully understanding the actual characterization.
Analog signals will be processed with the sub output being out of phase with the other channels. The sub output is in phase on digitally processed signals.

My question with regards to not using the analog sub input from my DVD player is inconsequential to this anomaly.

I think this happans at the analog section,and I have a feeling that if it's not the crossover itself,then it could be reversed wireing on either on the sub input or output.
Just for the record 2 out of 3 950's I had didn't exhibit this anomoly.

Dale, in order to find out that you have this problem play the identical disc say a music DD or DTS concert video for instance,and change the input from "6ch input" to DVD input,and vice versa.If there is phase shift you'll hear it.

Yes, listening to drums during the intro of Hotel California the bass was identically as prodigious in the 6ch analog mode as in the digital input mode. My 950 does not exhibit the reversal problem.
Seems like it could well be a miswire, and Outlaw should have a fix by now.




[This message has been edited by DaleB (edited June 29, 2003).]

Don't know if Outlaw fixed the out-of-phase problem or not, since Outlaw never acknowledged the problem existed, in the first place.

I have just read through this discussion thread quickly, so I am just barely informed. Perhaps someone with an A/B ‘scope and some RCA ‘Y’ connectors could do a simple test for us to determine if there is a 950 phase reversal problem. I would advocate this over “room listening” so that room effects are not a part of the test.

Source set-up: with either a sine-wave generator or a test disk playback set to play 60Hz, use a single output through a ‘Y’ adapter to give two in-phase signals. Add a second ‘Y’ adapter to the first ‘Y’ adapter to give three in-phase signals. Connect one of these signals to the Left Front input of the multi-channel inputs. Connect the second of these signals to the Sub input of the multi-channel inputs. Set the 950 to multi-channel mode with Analog Bass Management “off.”

Before testing the 950, directly connect the test signal to the ‘scope and check that the sine wave being used is ‘clean and nice.’ If any signal summing in the 950 or in the ‘A+B’ mode of the ‘scope shows and oddly shaped wave, then we are dealing with phasing other than at 0 or 180 degrees.

Tests 1 and 2, other connections: Connect the Sub output of the 950 to the ‘A’ input on the ‘scope. Connect the Left Front out of the 950 to the ‘B’ input on the ‘scope. First, look only the ‘A’ input on the scope (do not ‘A+B’ yet). Since the 950 will sum the 60Hz of the Left Front input with the Sub input, you will see the result of this summing on the ‘scope.

Test 1: Disconnect one of the ‘Y’ adapter inputs to the 950. If the amplitude on the scope drops, then you have shown that the two signals were in phase with each other as the inputs were summed. If the amplitude rises when one signal is disconnected, then the inputs were summed out-of-phase and disconnecting one of the inputs has taken away the cancellation effect, allowing the output level to rise. Assuming that with both inputs connected, the output is higher than with only one input connected, and that the sine wave still looks like a clean sine wave, Test 1 has a passing grade, meaning that the inputs are processed in phase with each other. If the output wave became oddly shaped (not a “nice” sine wave) when the two signals were summed, then the two signals are being summed somewhere between 0 and 180 degrees phasing with each other and we have found yet another problem.

Test 2: with the Analog Bass Management switch on the 950 set to “off” so that the 60Hz signal will be present on both the Left Front out and the Sub out of the 950, switch the ‘scope from ‘A’ only to ‘A+B.’ If the ‘A+B’ amplitude is higher than ‘A’ alone, without wave distortion, then we have shown that the outputs are also in phase. Test 2 is passed, meaning that the outputs are also in phase with each other.

Test 3, absolute phase: instead of the ‘B’ side of the ‘scope being connected to the Left Front output, connect the third leg of the ‘Y’ adapters to the ‘B’ input on the ‘scope. If the ‘A+B’ selection on the ‘scope provides a higher output than either ‘A’ or ‘B’ alone, then we have shown that the 950 provides an output that is in phase with the input while in the Multi-channel bypass mode.

If the inputs are in phase (Test 1), and the outputs are in phase (Test 2), then your listening will be OK regardless of whether there is any timing or phase shift seen in Test 3. Test 3 is only for the sake of “knowing.”

Why not test the difference between Multi-channel bypass and other modes? Because as long as any mode is in phase with itself, you only listen to one mode at a time, right? As long as the Sub remains in the same relative phase to the rest of the speakers in each mode, each mode by itself is OK. If one mode has a different phasing error within itself than another mode has, then “oops!,” we will not have consistency of speaker/sub phasing.

Oh, if you turned the analog bass management “off” for the testing, it may need to be turned back “on” again for your normal installation.

Remember, any phasing error between your regular speakers and your sub(s) produces problems only at frequencies being produced by both the regular speakers and the sub(s) simultaneously. Also remember, since the regular speakers are spread around the room, your subwoofer(s) can’t be exactly in phase with all your speakers at once anyway!

Bottom line: since we were here to talk about the 950 … if Tests 1 & 2 turn out OK, then any realized error is not because of the 950.

Mine did it with 2 different test discs. Chesky Ultimate DVD-A disc (has really good phase tests among other good tests), and you can also observe it with a simple discrete test tone CD. Play a tone at or near the crossover freq, then compare SPL measurements from the front 2 channels of the 6 ch input, vs a 2 ch input that is digitized. A couple of buddies of mine suggested it's due to the extra delay (i.e., processing) involved with the digital side and the crossing over of the mains to the sub. Not the same, but maybe the same, a dude on HTF spotted the same effect when using the ICBM with a Denon receiver. When one was in phase (digital or analog), the other was out.

Personally, I don't feel that listening to actual material necessarily reveals it on all systems. Not unless you specifically put the sub out of phase 1st so it's apparent what the effect is. You should know what to listen for 1st, to make it easier to tell betweeen 2 unknown signals.


[This message has been edited by Kevin C Brown (edited June 30, 2003).]

I would agree that it bears more testing. I recently ordered the Ultimate disk and plan to conduct more comparisons.
The phase test on the Avia disk may not be as revealing for the sub, but intentionally setting the sub out of phase may make any differences more apparent when changing form digital to analog modes. Something worth trying for sure.



[This message has been edited by DaleB (edited June 30, 2003).]