Level Diff. Between Audio/Aux v.s. Master Fader.

[[KGB]]

I have a concern/question concernig level variances between Audio & Aux tracks compaired to the Master Fader. The problem is this, if you create a single or multi. tracks, and create a test tone at say 1k and adjust the db to say -14db and then set the fader to 0. The Master Fader will show a level that is 2.5db LOWER then the original track. I have tried this with many aftermarket VU meters (PSP, Waves, Bomb Factory, Etc...) and they all show the same discrepancy. If the track is sent out an interface then brought back in, the level check remains the consistant -14db. the only way to have the Master Fader reflect the true -14db signal of the orig. track is to adjust the Master Fader to +2.5db above 0 . I have tried this scenareo with ever posiable combination, Stereo to Mono, Mono to Stereo, Mono to Mono, Etc... They all have the same result being the Master Fader is 2.5db LOWER . So there is no "summing" of tracks involved which was my original thought but that would actually cause the Master Fader to have a " Louder " level then a Lower level. I know this is fairly long winded, but is a HUGE problem with level inacuracies. This test was also performed on a PRO quality analog board and the results were even across the board, meaning the Master Fader's level was equaled to the original tracks. If anyone has an answer or explination i would greatly like to hear one. preferably with out the -14dbu = 0dbV mumbo jumbo, because that has nothing to do with it...

[gpgarner]

My only guess is Digi was trying to build in more headroom on the channel strip which would never "over" unless the recorded material clips. If you build in a db buffer on the Master Bus, you are less likely to clip if you choose to overdrive a few channels...However, its probably more of a throwback feature for people who came from a console background who are used to slamming everything...

[nukmusic]

I have also noticed something like this with input to an Aux track bussed to an Audio track. Sometimes the audio track will clip but the AUx track won't, even through the audio goes into the AUX track first. All faders set at Obd with no plug-ins.

[gpgarner]

I could see that happening though...if the plug your running through on your Aux input is adding any gain to whats hitting the Audio channel

[antiphase]

Check your pre/post fade button on the aux send

[tele_player]

I'm sure Rail will explain this better, but for now.

What you're seeing is normal, and correct.

Here's what I set up:
- stereo Master fader on normal stereo outs Analog 1-2
- a mono aux track, output set to Analog 1-2 (the normal out)
- insert signal generator on the aux, set sig gen level to -14
- set aux channel fader to 0

and the level that shows up in the Master fader is -16.5
Ok, that's what you're seeing. But that's really just the level on one side.

Now, assign the aux channel output to Analog 1 instead of Analog 1-2. You'll see the expected -14 on the Master.

Explanation (and here is where Rail will excel), when a mono signal is sent to a stereo output, it's reduced by 2.5db on each side. When the two signals (each reduced 2.5db) combine, the total comes back to 0. Some systems reduce by 3 (I think).

I don't know why it's 2.5db instead of 3 db, but I think I've seen a vallid explanation somewhere. Maybe it was in the manual.

[spkguitar]

I think this is the post where Rail explained it.

Interesting stuff.

[gYs]

Interesting stuff indeed....Does anybody have some more info on this panning law? What is it for and how and so on?

Rail??

Thanks.

[tele_player]

Do a google search for panning law, you'll find some interesting stuff. There's actually quite a bit of science and math behind exactly how faders should work to pan a sound across the stereo field.

[[KGB]]

That make sences and seems to be the case, but why does this not hold true for ANALOG concoles?