Comb filtered swept sounds more resilient to spectral masking?

[jappe]

I've had this experiment idea on the todo list for a long time, but for some reason I haven't yet investigated it.

My thought is that swept comb filtered sounds, and other sounds with timbre that changes sufficiently quickly, should be less vulnerable to spectral masking.
A bit like a person hiding camouflaged in nature is more likely to be seen if moving.

I'm thinking swept comb filtering and similar could then be one of the tools to make sounds (with rich spectral content) stick out in order to fit several thick sounds in a mix?

I guess there's also temporal masking that could cause problems with this idea.

I know there are plenty signal processing experts in here that could either approve or reject this idea based on hardcore technical facts. Let me hear you tech wizards sing plz

I myself tend to get dizzy these days when reading includes a lot of numbers and formulas, so I've still on my todolist (since years back) to complete the book "Psychoacoustics" (by E. Zwicker) which discusses relevant topics.

[ScuzzyEye]

Won't comb filtering remove some (much?) of the spectral content?

[jappe]

Won't comb filtering remove some (much?) of the spectral content?

Ah yes, but so does EQing for fixing masking issues. I'm thinking the sounds would be thicker still, since you make many small cuts rather than a few slaughter cuts. (or pick a thin non-equed sound from the start)
Rather than the thinny sounds you can pick out from a mix when soloing it.
The philosophy would be: "there's always some part of the spectrum heard for each sound since it's not likely that all components are masked at the same time"

[avasopht]

I think I get what you're suggesting, is it basically down to the idea of alternating between which sounds are in the forefront, using the sweeping combs to achieve this?

If so then it will play much the same role as a LFO cross fade between sound sources, which might be a simpler and likely more effective technique.

[ScuzzyEye]

As long as you're aware that, I'm in agreement. I like how comb filtering sounds. That's probably because it's part of all real world sounds, as reflections cause constructive/destructive interference. If for that reason alone, it may make a sound stand out more, because it just becomes more natural sounding. You might also consider different settings for both the left and right filters.

Ultimately it's difficult to predict psychoacoustic effects. There are models, but they only take into account what's known. If you start exploring a new effect that the model doesn't account for, it won't offer useful data. Just try it and see how it sounds.

[jappe]

I think I get what you're suggesting, is it basically down to the idea of alternating between which sounds are in the forefront, using the sweeping combs to achieve this?

Well actually I'm hoping that with this technique it's not (ideally) alternating the sounds like forefront/background but rather that two competing sounds can be at the forefront all the time - but with an alternating dominant spectral fingerprint in each sound that allows it to be heard all the time - just possibly not the same spectrum components for every note.

[jappe]

As long as you're aware that, I'm in agreement. I like how comb filtering sounds. That's probably because it's part of all real world sounds, as reflections cause constructive/destructive interference. If for that reason alone, it may make a sound stand out more, because it just becomes more natural sounding. You might also consider different settings for both the left and right filters.

Ultimately it's difficult to predict psychoacoustic effects. There are models, but they only take into account what's known. If you start exploring a new effect that the model doesn't account for, it won't offer useful data. Just try it and see how it sounds.

Ah I love comb filtering/PWMish sounds since I heard it the first time.
It's interesting that we perceive it so well sounding and rich.

Perhaps it's because there is some blurring going on in our brain when a sound morphs from one static sound to another. Like our brain makes us concentrate on what on earth is happening with the sound - hearing has been important for human survival.

A bit like a slow camera autofocus trying to focus on a constantly moving object. A way to make humans focus on a (spectrally) moving sound, is to have a brain that rewards listening to it, perhaps therefore we perceive those sounds are pleasant.

[ScuzzyEye]

A simple but effective trick that I've done, is to take a mono signal, and send it into a mid-side decoder. Using the original mono as the mid, and a second copy of that same audio, but delayed a few ms, as the side. When it is decoded back to stereo you get comb filtering, with the combs 180 degrees out of phase between the left and right. So that might be something to try with the LFO that's driving your comb, use the inverted phase of drive the right. Maybe even mix a little of the non-filtered signal into the middle.

[jappe]

A simple but effective trick that I've done, is to take a mono signal, and send it into a mid-side decoder. Using the original mono as the mid, and a second copy of that same audio, but delayed a few ms, as the side. When it is decoded back to stereo you get comb filtering, with the combs 180 degrees out of phase between the left and right. So that might be something to try with the LFO that's driving your comb, use the inverted phase of drive the right. Maybe even mix a little of the non-filtered signal into the middle.

Thank's for sharing, an interesting thing to try!

[selig]

I would guess that even in the best case, you end up with a comb filter effect where you might not want one. Maybe you can explain the issue you are trying to address, as I'm not sure I'm following the reasoning behind wanting this.

In a related note, I've heard of using a comb filter on one track, and the inverse comb on a copy (panned opposite) to create a pseudo stereo effect.

It's not uncommon to use EQ and the inverse EQ to "Make space". But by far the best way to address these issues is with the arraignment and choice of sounds - just IMO, of course. If you mix other folk's projects, as I often do, this may not be an option. In these cases I sometimes have to simply make an executive decision and mute some tracks in some places in order to establish each track on it's own before allowing them all to co-exist - once the listener has heard each track you can then allow them to be slightly swallowed up by the rest of the tracks.

You basically have two "tools" at your disposal, Time and Frequency. My advice: Don't try to address these sort of issues by Frequency alone…

[jappe]

I would guess that even in the best case, you end up with a comb filter effect where you might not want one. Maybe you can explain the issue you are trying to address, as I'm not sure I'm following the reasoning behind wanting this.

In a related note, I've heard of using a comb filter on one track, and the inverse comb on a copy (panned opposite) to create a pseudo stereo effect.

It's not uncommon to use EQ and the inverse EQ to "Make space". But by far the best way to address these issues is with the arraignment and choice of sounds - just IMO, of course. If you mix other folk's projects, as I often do, this may not be an option. In these cases I sometimes have to simply make an executive decision and mute some tracks in some places in order to establish each track on it's own before allowing them all to co-exist - once the listener has heard each track you can then allow them to be slightly swallowed up by the rest of the tracks.

You basically have two "tools" at your disposal, Time and Frequency. My advice: Don't try to address these sort of issues by Frequency alone…

I agree about choice of sounds: I have started to understand the importance of selecting good sounds from the start - I always used to use whatever sound I found nice and then cut a lot. And in fact I think I remember some discussion from PUF when I believe you mentioned it.

The issue I'm trying to adress is to get an answer to my curious mind if it would be possible to use spectral sweeps as one tool in the toolbox to use when trying to make sounds heard in the mix; together with the other tools like panning, choice of sounds, EQuing, arrangement.
For example if you have a harmonically rich but kind of static pad sound, highly likely to clash with other sounds, if it would help the other sounds to stick out more after you induce some amount of spectral movement in that pad.

I'm also interested in understanding if the fact that a sound sticks out in a mix also means that it cannot be even more improved?
And with improved I mean: can the rhythm of the sound that sticks out OK be made even more distinct than just barely hearing it in the mix, using this technique?

(I know, I should be experimenting with this already instead of writing here, but I also happen to enjoy discussing things and thoughts like this since it helps me to understand things both when I write it down and when I read the replies

[selig]

I would guess that even in the best case, you end up with a comb filter effect where you might not want one. Maybe you can explain the issue you are trying to address, as I'm not sure I'm following the reasoning behind wanting this.

In a related note, I've heard of using a comb filter on one track, and the inverse comb on a copy (panned opposite) to create a pseudo stereo effect.

It's not uncommon to use EQ and the inverse EQ to "Make space". But by far the best way to address these issues is with the arraignment and choice of sounds - just IMO, of course. If you mix other folk's projects, as I often do, this may not be an option. In these cases I sometimes have to simply make an executive decision and mute some tracks in some places in order to establish each track on it's own before allowing them all to co-exist - once the listener has heard each track you can then allow them to be slightly swallowed up by the rest of the tracks.

You basically have two "tools" at your disposal, Time and Frequency. My advice: Don't try to address these sort of issues by Frequency alone…

I agree about choice of sounds: I have started to understand the importance of selecting good sounds from the start - I always used to use whatever sound I found nice and then cut a lot. And in fact I think I remember some discussion from PUF when I believe you mentioned it.

The issue I'm trying to adress is to get an answer to my curious mind if it would be possible to use spectral sweeps as one tool in the toolbox to use when trying to make sounds heard in the mix; together with the other tools like panning, choice of sounds, EQuing, arrangement.
For example if you have a harmonically rich but kind of static pad sound, highly likely to clash with other sounds, if it would help the other sounds to stick out more after you induce some amount of spectral movement in that pad.

I'm also interested in understanding if the fact that a sound sticks out in a mix also means that it cannot be even more improved?
And with improved I mean: can the rhythm of the sound that sticks out OK be made even more distinct than just barely hearing it in the mix, using this technique?

(I know, I should be experimenting with this already instead of writing here, but I also happen to enjoy discussing things and thoughts like this since it helps me to understand things both when I write it down and when I read the replies

For me, the color and obvious "phaser" effect of a swept comb filter is a sound I choose when I want the "phaser" effect - not something I'd do SOLELY to help my mix. That was my main point. It's like saying that running a sound through a Marshall amp at 11 helps a sound cut through - sure, but now it sounds like it's run through a Marshall at 11…