KVR Audio

brekehan · Post by **brekehan** » Thu Jan 22, 2015 7:00 am

This is an example of what happens to me all the time. If I try to take out some low end on a particular track, the volume goes up. When I expect to have more headroom, I get less. If I bring it back to equal volume, it sounds like shit when A/B. Why do I get more volume instead of less?

https://www.youtube.com/watch?v=DPhdDk1aSJU

manducator · Post by **manducator** » Thu Jan 22, 2015 7:24 am

I couldn't understand a word in the video because the music was too loud but since you demonstrate it in a full mix, it could have something to do with masking (phase cancellation).

If there's phase cancellation going on with bassline and kick, the volume will decrease. When you cut out the phasing frequencies in one of those instruments, you make room for the other (and euhm... cancel the cancellation). This could result in higher volume.

brekehan · Post by **brekehan** » Thu Jan 22, 2015 7:32 am

manducator wrote:I couldn't understand a word in the video because the music was too loud but since you demonstrate it in a full mix, it could have something to do with masking (phase cancellation).

If there's phase cancellation going on with bassline and kick, the volume will decrease. When you cut out the phasing frequencies in one of those instruments, you make room for the other (and euhm... cancel the cancellation). This could result in higher volume.

The readings are the same even when I solo the bassline track. I can even delete the other tracks and get the same result. Also, I could see phase cancellation effecting the master level, but nothing is coming through the channel shown except the bassline. So, I am confused.

I can also swap out the particular plugin for another EQ and the same thing happens.

Made another video (take 2) soling the bassline channel and turned my mic up:
https://www.youtube.com/watch?v=R0QLLTDjmVE

itneveris · Post by **itneveris** » Thu Jan 22, 2015 9:34 am

Is it just Pro-Q doing this?

Auto-Gain must be on.

manducator · Post by **manducator** » Thu Jan 22, 2015 9:37 am

Mmmh, nope, that's no problem with phase cancellation.

Maybe it has something to do with intersample peaks? Have you tried activating and de-activating oversampling on the eq plugin?

I made a bassline in reaper, opened rea-eq on it, did a highpass and the volume went down, as expected.

nIGhT-SoN · Post by **nIGhT-SoN** » Thu Jan 22, 2015 9:38 am

+1^

You most likely have Auto-Gain on and when you cut low freq which have a lot of energy (depending on the material), it will bring up the volume.

manducator · Post by **manducator** » Thu Jan 22, 2015 9:41 am

itneveris wrote:Is it just Pro-Q doing this?

Auto-Gain must be on.

In the second video you can see clearly that there's no autogain or whatsoever and it also happens with builtin eq. Those aren't the problems.

I think it has something to do with oversampling, or the lack of oversampling.

It could be the same problem as with rendering wav files to mp3's: a wav file can have peaks not going over -0.1 dBFS but the mp3 will go in the red by 1 dBFS.

Burillo · Post by **Burillo** » Thu Jan 22, 2015 12:04 pm

i might be talking out of my ass right now as i can't watch the video right now and can't see what's it all about. however, usually this question is asked because people don't understand physics. (apologies if this isn't the case)

lower frequency waves have more energy. therefore, if you cut low end, you can bring the overall loudness higher. if you have a limiter on your master (or a compressor somewhere on the way between the sound source and your ears) that's always working through lots of dB's of gain reduction, cutting low end would indeed result in more volume, since the very low end is not kicking the limiter as hard any more.

IIRs · Post by **IIRs** » Thu Jan 22, 2015 9:34 pm

Its not phase cancellation, its phase shift

Try running a sawtooth wave through an allpass filter (ie a filter that only changes phase) and watch your peak levels change as you sweep the cutoff around...

Note that its only peak levels that change, as the waveform changes shape. The volume (ie apparent loudness) does not change.

brekehan · Post by **brekehan** » Thu Jan 22, 2015 11:51 pm

IIRs wrote:Its not phase cancellation, its phase shift

Try running a sawtooth wave through an allpass filter (ie a filter that only changes phase) and watch your peak levels change as you sweep the cutoff around...

Note that its only peak levels that change, as the waveform changes shape. The volume (ie apparent loudness) does not change.

From what I've researched online, phase shifting is an artifact of analog EQs, sometimes liked for its character. While some digital EQs might emulate it, surely, not all of my EQs do, do they? I don't know how to tell if Fab Filter Pro Q2 does or doesn't for certain unless one of their devs answer my query too.

Suppose we do have and accept the explanation. What does one do when this happens? I need to cut the low-end from the bassline in order to not collide with my kick, but in so doing lose headroom. If I bring it back to -6db after equalization, it seems I have lost quite a bit of perceived volume. Meanwhile, everything I've read online seems to claim that it is a good idea to cut your bass instruments close to the base frequency of the boom in the kick and to cut the kick around 250-300 range to make room for the bass instrument. (in general)

This isn't one isolated incident either, although it is one of the more extreme ones I've run into. This happens to me all the time, in fact almost every time. Whether it be a kick drum, a bass instrument, a mid range synth, or a cymbal, if I cut the low frequencies out the volume on the track according to the mixer increases.

One desires to "bracket" the sound of each track to unclutter the mix, but in so doing, it seems I am killing the sound more than making it better.

geroyannis · Post by **geroyannis** » Fri Jan 23, 2015 12:05 am

Check what Burillo said. Turn off any compressor/limiter on the master buss and see if the problems persists.

brekehan · Post by **brekehan** » Fri Jan 23, 2015 12:10 am

geroyannis wrote:Check what Burillo said. Turn off any compressor/limiter on the master buss and see if the problems persists.

There are none. No compressor, no limiter, no bus.

One track, one instrument, one EQ, out to speaker. I can do this in Live9 and Cubase 8 too, with virtually any instrument that has any low frequency content.

geroyannis · Post by **geroyannis** » Fri Jan 23, 2015 12:22 am

Ha ha, I'm sorry, this doesn't make any sense!
At all.

Is there a dsp compressor loaded on the control panel of your sound card?
Also, does it happen when listening through headphones? Cause maybe it could be a speaker wired out of phase... Can't think of anything else.

nineofkings · Post by **nineofkings** » Fri Jan 23, 2015 12:39 am

This is a common problem. So common, I can't believe so many have never experienced it. IIRs has the right answer. Phase shift is a fundamental side effect of EQing audio; it has nothing to do with emulating vintage hardware (although vintage emulations will certainly do it). The reason "linear phase EQs" exist is because it takes a specially designed type of EQ - with considerable latency - to avoid changing the phase of the audio. Low cuts shift the phase of low frequency audio, which is very energetic, and therefore decrease headroom. But the other benefits of low cutting in a full mix outweigh a small increase in amplitude.

CableChannel · Post by **CableChannel** » Fri Jan 23, 2015 12:50 am

EQs often have an overshot in the freq response, the graphical representation is too coarse to show this.

Why louder volume when EQ cut?