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Timestretching Before Compressing
Posted: Sun Jan 22, 2012 1:01 am
by SunkLo
I was just thinking... What if you timestretched a .wav way out before you limited/compressed it and then stretched it back? I'm thinking this would lead to cleaner compression with less artifacts.
You'd probably have to tweak the release time a bit so it sounds natural when you speed it back up again. I'm also wondering if you used a varispeed algo to do the timestretching, it would emphasize different harmonics and possibly push the distortion into the supersonic range?
Anyone tried this or thought about this before?
Thinking it could be useful for limiting mixes or compressing percussion and other instruments.
Might do some experiments with paulstretch too...

Re: Timestretching Before Compressing
Posted: Sun Jan 22, 2012 3:47 am
by dubesteppe
interesting concept. i tried it on some drums and flutes. everything i did didnt have favorable outcomes.
Re: Timestretching Before Compressing
Posted: Sun Jan 22, 2012 1:51 pm
by futures_untold
Remember that all a compressor does is change the volume envelope of the sound.
So if you time stretch some audio and bring up your volume automation lane, you could zoom right in and tweak the exact points that the volume changes.
Re: Timestretching Before Compressing
Posted: Sun Jan 22, 2012 3:07 pm
by therapist
futures_untold wrote:Remember that all a compressor does is change the volume envelope of the sound.
So if you time stretch some audio and bring up your volume automation lane, you could zoom right in and tweak the exact points that the volume changes.
Is that strictly true? Surely sounds below the threshold are unaffected, other compression wouldn't have a 'sound' it would just be volume?
Not sure I follow the original idea in this thread but it's interesting.
Re: Timestretching Before Compressing
Posted: Sun Jan 22, 2012 3:35 pm
by Aphile
therapist wrote:futures_untold wrote:Remember that all a compressor does is change the volume envelope of the sound.
So if you time stretch some audio and bring up your volume automation lane, you could zoom right in and tweak the exact points that the volume changes.
Is that strictly true? Surely sounds below the threshold are unaffected, other compression wouldn't have a 'sound' it would just be volume?
Not sure I follow the original idea in this thread but it's interesting.
if the material has been timestretched, consider how long a C attack time is. Milliseconds. When played at normal time, a compressors attack will effect a certain percentage of the track if you will. Now, with the music slowed down by timestretching, the previous attack time will now effect MORE time in the material.
Re: Timestretching Before Compressing
Posted: Sun Jan 22, 2012 6:26 pm
by therapist
Aphile wrote:therapist wrote:futures_untold wrote:Remember that all a compressor does is change the volume envelope of the sound.
So if you time stretch some audio and bring up your volume automation lane, you could zoom right in and tweak the exact points that the volume changes.
Is that strictly true? Surely sounds below the threshold are unaffected, other compression wouldn't have a 'sound' it would just be volume?
Not sure I follow the original idea in this thread but it's interesting.
if the material has been timestretched, consider how long a C attack time is. Milliseconds. When played at normal time, a compressors attack will effect a certain percentage of the track if you will. Now, with the music slowed down by timestretching, the previous attack time will now effect MORE time in the material.
I was talking about the actual effect of the compression rather than how time-stretching will affect it, but yeah.
Re: Timestretching Before Compressing
Posted: Sun Jan 22, 2012 8:16 pm
by Aphile
therapist wrote:Aphile wrote:therapist wrote:futures_untold wrote:Remember that all a compressor does is change the volume envelope of the sound.
So if you time stretch some audio and bring up your volume automation lane, you could zoom right in and tweak the exact points that the volume changes.
Is that strictly true? Surely sounds below the threshold are unaffected, other compression wouldn't have a 'sound' it would just be volume?
Not sure I follow the original idea in this thread but it's interesting.
if the material has been timestretched, consider how long a C attack time is. Milliseconds. When played at normal time, a compressors attack will effect a certain percentage of the track if you will. Now, with the music slowed down by timestretching, the previous attack time will now effect MORE time in the material.
I was talking about the actual effect of the compression rather than how time-stretching will affect it, but yeah.
why would the effect of the compression be any different? the slopes of the gain reduction graph on the time stretched audio. would be much sharper than those with the same setting applied on an untimestretched sample
Re: Timestretching Before Compressing
Posted: Sun Jan 22, 2012 8:27 pm
by e-motion
Doesn't stretching then reducing introduce artifacts on it's own?
Re: Timestretching Before Compressing
Posted: Sun Jan 22, 2012 8:27 pm
by therapist
I think you got the wrong end of the stick somewhere. I was only responding to what Futures said about compression,
Re: Timestretching Before Compressing
Posted: Sun Jan 22, 2012 8:50 pm
by VirtualMark
Time stretching would introduce its own artifacts, as its based on granular processing. What would keep the sample cleaner would be to pitch it down and back up again.
Anyhow, as others have said, all this would do is to make the compressors attack and release faster. You could do this by changing the settings on the compressor. I suppose if you wanted super fast compression for some reason then you could use this method, but i can't really see a need for it.
Re: Timestretching Before Compressing
Posted: Mon Jan 23, 2012 12:49 am
by SunkLo
Well different time stretching algorithms work differently. That's why I proposed varispeeding it down so that when you speed it back up it pushed any distortion into the super sonic range.
Point of it is, to give the limiter more time to react, attack phase gets shrunk when you stretch it back to normal. Kind of like a more organic version of look ahead. Hopefully this would sound cleaner and introduce less distortion. More useful for really dynamic material.
Also might make it easier to dial in attack and release and threshold perfectly.
Re: Timestretching Before Compressing
Posted: Mon Jan 23, 2012 3:08 am
by Artie_Fufkin
Wait, why couldn't you slow down the audio without affecting pitch/tape speed slowdown and then speed it up after?
Something kinda related to this idea is a technique I read about on gearslutz where you reverse the audio and then compress and then reverse it back. This changes the way the compressor reacts also.
Re: Timestretching Before Compressing
Posted: Mon Jan 23, 2012 2:43 pm
by JTMMusicuk
Artie Fufkin wrote:Wait, why couldn't you slow down the audio without affecting pitch/tape speed slowdown and then speed it up after?
Something kinda related to this idea is a technique I read about on gearslutz where you reverse the audio and then compress and then reverse it back. This changes the way the compressor reacts also.
congratulations you have submitted some useful information into a somewhat ridiculous thread
Re: Timestretching Before Compressing
Posted: Mon Jan 23, 2012 8:45 pm
by ketamine
JTMMusicuk wrote:Artie Fufkin wrote:Wait, why couldn't you slow down the audio without affecting pitch/tape speed slowdown and then speed it up after?
Something kinda related to this idea is a technique I read about on gearslutz where you reverse the audio and then compress and then reverse it back. This changes the way the compressor reacts also.
congratulations you have submitted some useful information into a somewhat ridiculous thread

Re: Timestretching Before Compressing
Posted: Mon Jan 23, 2012 9:14 pm
by Kaslo
timestretching it will
generate the artifacts... Not sure how you're coming to the conclusion that it'll sound cleaner
