Speaker Level Disparity

[glaufman]

I was over a friend's house, and he goaded me into running some scans with his equipment...
First scan showed almost no bass response below the cutoff, so we disconnected the mains, and showed little difference where the sub should be operating, so we stepped back and set the speaker levels... here's where it gets good...
His AVR has no internal test tone that he can operate (only through the remote, which he does not have, and cannot find the correct code to program into his universal), so he originally ran a test tone from a DVE BD... as long as we had REW running and connected to his multi ins, we used it's generator, I think it was periodic pink noise... had to turn the sub way up on the AVR, and also the level knob on the sub itself to get the correct levels... then we re-ran the scan and saw some activity in the bass frequencies, albeit with lots of nasty modes, we'll get to those in a few months...
Since he watches through the optical input from his BD, we then reset the levels again, going back to the DVEBD... interestingly enough, these settings were identical to the settings we got when we tried using REW's generator through the optical input (even though this wouldn't be DD)...

So first question is, did I do right? Am I missing something?

This is obviously why it's good to use the AVR's built in test tone for setting speaker levels, as it should be injected after the surround processing sections, but does this present an issue when running any kind of REW scans as for speaker levels? I've seen one other time when I set levels on a cousin's systeem, then run a scan, and clearly the mains were 5-10db below the sub...

[PT800]

It sounds like the sub needs to be moved to another location, and/or the sub doesn't have enough power. Or maybe the sub's phase is wrong for its location.
The sub's volume control should not be all the way up or the AVR's sub level.

It shouldn't make much, if any difference, when setting levels with either internal AVR pink noise or using a dvd. I've used both and the levels don't change much, if at all.

[glaufman]

It seems I forgot to mention that at some point we connected REW using an optical cable, went back to the REW PPN to set levels, and then ran a scan which showed plenty of bass response, mody as it may have been... like I said, we'll fix that later... for now...

Subwoofer placement and phasing shouldn't give different levels when using different inputs... it's not so much the "source" difference I'm questioning, as it is the inputs, how they're coded, and therefore how the AVR treats them... i.e. optical DD vs. optical PCM vs analog multi...

[glaufman]

Also I failed to mention that when setting levels throughj the optical input, left the level on the sub set at "THX" and the correct setting in the AVR was nowhere near max... only had to turn both up when using the analog multi ins...

[PT800]

glaufman wrote:

Also I failed to mention that when setting levels throughj the optical input, left the level on the sub set at "THX" and the correct setting in the AVR was nowhere near max... only had to turn both up when using the analog multi ins...

My experience is when using analog bypass for DVD-A/SACD that I have to turn down the volume, as its generally 10db higher than the digital outputs.
And different MC modes can have different levels and need to be set for each mode. With my HK AVR the Logic 7 surround modes are louder than the DD modes, if the AVR is set using common trim levels instead of individual trim levels, for each surround mode.

And I remember having different levels between coax and optical inputs, when I was using both.

[glaufman]

Interesting...I don't believe this AVR (or mine for that matter) has the ability to remember different speaker levels for different modes/inputs... mine does have different eq settings for each mode, but not this one...

I figure in some ways what it's doing is excusable, as in DD rthe LFE track is recorded at -10db for additional headroom, so the AVR presumably gives the LFE a 10dB boost before bass redirection, so inputting the identical signal into each channel should result in a 10dB increase in level from sub to mains, but I wouldn't have expected to see this effect using REW, as the AVR would not have been in DD mode.