Page 1 of 1

Slowed down compression

Posted: Wed Dec 05, 2012 12:53 pm
by HighBot
Has anybody experimented or had any success with this?
The idea is to slow down a bounced version of your drums or whatever, by re-pitch (so no audio degradation is introduced), adding a compressor with far higher values than you normally would, giving the compressor more time to work and more precise adjustments, bouncing that and then speeding it back up. (again repitch to save the quality)

Re: Slowed down compression

Posted: Wed Dec 05, 2012 1:08 pm
by VirtualMark
There's no real need - lots of compressors have extremely low attack times and oversampling. Best to just set it by ear, then you know what you're getting.

Re: Slowed down compression

Posted: Wed Dec 05, 2012 2:56 pm
by Sharmaji
Nothing is as destructive as re-pitching, so there's no way you're gonna get something w/o artifacts using this method.

W that said, reversing audio, compressing it quite strongly and then reversing it back is a time honored tool. Works well on vocal bits that need to be heavily compressed but not sound so.

Re: Slowed down compression

Posted: Thu Dec 06, 2012 5:23 am
by Artie_Fufkin
How does it create artifacts?
I made a sine tone in audacity and then duplicated it, pitched it down, then up back to its original pitch, inverted it and summed it so I could hear these artifacts. How is this difference being made?

Re: Slowed down compression

Posted: Thu Dec 06, 2012 10:15 am
by VirtualMark
Artie Fufkin wrote:How does it create artifacts?
I made a sine tone in audacity and then duplicated it, pitched it down, then up back to its original pitch, inverted it and summed it so I could hear these artifacts. How is this difference being made?
It's called interpolation - it's why most samplers have a quality setting. It helps me to think of a digital image - if you resize it, some of the pixels will fall between the grid and need to be shifted.

With audio we use a fixed grid, determined by sample rate and bit depth. So when you pitch up or down the waveform has to be rearranged to fit on this grid. If you pitch it down, you need to fill in the gaps and if you pitch it up you need to remove parts.

Re: Slowed down compression

Posted: Thu Dec 06, 2012 11:22 am
by HighBot
Ahh cool. Guess I can forget about that one so haha!
I'll stick to my multiband so. Really enjoying the multi comp on Izotope Trash at the minute.
Slower attack times on the mid than the lows and highs help create a real heavy sound.

Re: Slowed down compression

Posted: Thu Dec 06, 2012 9:04 pm
by Artie_Fufkin
Oh, ok I was just reading about that. dBlue made this graph that explains the different methods
Image

Would this still be an issue if you used a 96kHz sampling rate?

Re: Slowed down compression

Posted: Thu Dec 06, 2012 10:31 pm
by VirtualMark
Yeah the issue will be there at any sample rate, but the higher sample rate gives better resolution and makes it less noticeable. I found this article that might be useful.

I wouldn't let it stop you from experimenting with creative fx, it can be fun to pitch and add reverb or distortion then pitch back. But as far as pitching to improve sound quality goes - i don't think there'd be anything to gain.