Question to audio engineers

[JoPo]

I'd like to know if I get the same amplitude sound reduction when I lower mixer channel gain of, for instance, 3db on a channel where the gain fader was, let's say, -5db ; and another channel lower of 3db too but that one, its fader was at -17db. Will those both channels keep the same relative power difference ?

Or, the same question asked in different way : if I lower all mixer channels of 3db, do I keep the same relative sound amplitude between all the channels ?

I hope you understand my question...

Many thanks !

[garyb]

pretty much.
it's not too smart to completely rely on your eyes, because that's not how your ears work, but for government work, the visual method is good enough(usually).

[JoPo]

Excellent. Thanks a lot, Garyb.

Yes, amplitude reduction can't be completely linear to our ears, it must depend on other factors such as frequency, pan... Anyway, it's reassuring ! It would be too complicated, otherwise...

I'm affraid I'll work like some government, thus...

[stonberg]

AIUI, both the db measurement system and our ears are logarithmic (i.e. equal power ratios are perceived as equal volume steps).

Another way to go about it ofc is to bus the signals together and cut the bus by 3db; in a good mixer this should be equivalent to cutting both channels by 3db then mixing together.

[garyb]

yes, faders are logarithmic and ears kinda are.

[dawman]

Then theres the Fletcher Munson curve......

[JoPo]

Then theres the Fletcher Munson curve......

Excellent ! I've heard but it is true that we must always have it in mind.

A channel with a lot of 3->4 khz frequency will not affect the mix like another one full of bass frequencies when moving their gain faders ; because of Fletcher.

Thanks for that good knowledge !

[hubird]

PsyQ --> FM curve

[garyb]

PsyQ --> FM curve

well, not really. the FM curve is related to changes in human hearing freq response relative to volume.

the PsyQ is like an Aural Exciter. it adds distortion at specific frequencies to the audio. it also is similar to the BBE process, time frequency alignment....it's called a Psycho-Acoustic EQ. the only way that it might be able to mimic FM response is if it was a realtime device that changed the eq settings as you raised and lowered the volume. Fletcher-Munson adjustment was what the "loudness" button was for in stereos made in the 70s and 80s.

[hubird]

It sounds like a (welcom) dip in the mids...in favour of the extremes

[garyb]

well, it can be used that way...
it's not related to phon curves, though.