Backwards Compression?

Hi all, I was reading through an old write-up of @ColdRoomStudio’s on his mix of a “Clockwork Clown” (A fHumble journey) which was unfortunately before my time here. In it, Andrew mentions a tutorial he wrote up on “Backwards Compression”, and supplied a link pointing to the old RR forum. (Incidentally, he Recording Review URL has been taken over.)

Is there any chance that any of you have a write-up or tips or can point me to a video on this technique? It’s a new one to me and I’m curious to find out about it. Thanks!

You are talking about expansion, right?

Drawmer used to do that on their old hardware compressors… DL231. Try looking that up.

Otherwise you could try a parallel compression if you have the uncompressed signal too.

Hey Mike, the original concept came from a column I read in Australia’s “Audio Technology” magazine. The column was written by Mike “Stav” Stavrou who wrote a book called “Mixing With Your Mind”. I haven’t read the book personally, but I’m pretty certain he writes about it there:

I’m at work at the moment, so I don’t have time to explain it now. I’ll see if I have anything on file when I get home.

No, definitely not expansion - this is what you would call an “oblique strategy”. Stav is very much a lateral thinker.

I don’t want you to have to re-write the thing! I was hoping someone may have saved a copy or something. I’ve run across the “Mixing With The Mind” book and it is on my radar as a “someday” read. Now it’s towards the top!

Here’s my guess on the technique based on the little you mention it (and this is a wild guess since I couldn’t find anything on it): Do you actually run the audio backwards and compress it? If so, perhaps the result is a much smoother compression since the plosives and consonants that start words are the loudest part of the wave, and they are also at the beginning. By flipping the audio it’s like having a huge “look ahead” since your compressor is starting at the back end of the sounds where it is the quietest and working towards the louder part. (?) So… your compressor is already compressing when the initial attack of the sound hits. (??) Does it leave the transients nicely intact, but simply gained down?

Thinking of typical compression, if you want the initial transient, you need to have a slow attack so it comes through BEFORE the comressor clamps down. Does compressing backwards have the effect of simply turning down that initial transient - like clip gaining it?

I’m so excited! I feel like I just stumbled on a “secret” mixing nugget - only all of you old RR guys have known about it for years.

Now I’m going to go google that article! Thanks! :nerd_face:

That’s pretty much it… only it’s different to a look-ahead compressor. The trick is that the compressor is acting in response to the waveform running backwards. The big downside of it is that it’s impossible to hear the results in real time.

Attack and release settings are definitely important.

No exactly… but it can help.

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Thanks Andrew. What an interesting idea!

I can see how that could be a big hindrance…

I found this discussion on the old Cakewalk forum. I was half expecting you to be in there. :slightly_smiling_face:

Here’s another article I found. The first section goes over “reverse compression”, then he talks about some other techniques to try out.

Yep, then render the output and reverse it. I used to do it on every bass guitar track I mixed, but ultimately I realised I could do a better job of it myself without the technique.

So why on your bass tracks - because it creates uniform compression? Or is there a “quality” about it that you like? Any settings you recommend?

I’m going to just have to try it out to see how it works. It does seem like quite a few steps, especially if you can get similar results another way.

It’s a different sound that you can’t really get from a normal compressor. You could come close to approximating it, but it would require quite a bit of lookahead. It’s just a different sounding compression. If it wasn’t so much work to do, I’d use it more often.

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I played with it a bit back back when fH first posted on RR and there was quite a bit of chat about it… tried it to tame some vocals and it definitely smoooothed some transients but wasn’t enough difference to make it worth the bother for me but… it was great fun playing around with the reversed audio and I’d forgotten about that, must play with that again one of these days :wink:

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Yes that was the main reason. To be honest it’s not a game-changer. If it had any kind of significant effect everyone would be doing it.

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From the remarks here is does sound like it was kind of a “fad” - a labor intensive one at that. I haven’t had a chance yet, but I am curious to try it out.

I found it quite useful when my computer was less powerful. It was great for relatively transparently leveling a dynamic vocal before applying standard processing without using up all my cpu. These days, I tend to use 3 or 4 compressors on a lead vocal, each doing just a little bit.

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I tried it and put up a poll. Please wander over and vote for the snippet you like, then I’ll reveal the backwards compressed clip.

Here it is:

Hi all,
@miked This is what I have from RR days.
And I am 99% sure it came from Andrew @ColdRoomStudio.

Here goes:

Put your best sounding compressor on your vocal track - squash it until it evens out the dynamics without detrimentally affecting the sound, once you’re happy, then squash it some more, & at this point it may be creating some artifacts - but not ridiculous. Ok, now get that vocal track & reverse it - yes, turn it around so that it plays backwards (you can do this easily in most DAWs. Now, bounce down that reversed vocal, including the heavy compression to another track. Take the bounced track & reverse it again, so that it now plays forward… Hopefully at this point, you’ll hear a lovely, highly compressed vocal without those nasty artifacts… Here’s how it works - When the vocal goes into the compressor backwards, the compressor “sees” and thus reacts to a completely different (much smoother) waveform, allowing much heavier-handed use of compression than you would use on the same track forwards. When I read about this technique, I was blown away - its a highly innovative chunk of lateral thinking, the credit for which lies with an engineer called Michael Stavrou, who has a book called “Mixing With Your Mind”. I tried it & I was blown away by how well it works. BTW, keep your original uncompressed vocal track, just in case, as this is a “destructive” process.

Edit I have uploaded an example for those viewing the thread for the first time…
Not sure if this is the best possible demo - I’ve posted the original file unprocessed. I then whacked UAD’s 1176SE plugin on the “All buttons in” mode smashing it with up to 20db gain reduction - that’s the second file… the last one has the same compression setting, but backward. Hopefully you can clearly hear the difference.


Thanks George! …and of course Andrew. :slightly_smiling_face: