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Gear / Technical Help => Post-Processing, Computer / Streaming / Internet Devices & Related Activity => Topic started by: achalsey on October 20, 2013, 02:37:01 AM

Title: Compression question: Is what I'm doing helpful or harmful?
Post by: achalsey on October 20, 2013, 02:37:01 AM
I don't know anything about compression, but I tried it and it seemed to do something helpful.  Is this okay?  I took the input numbers pretty much at random.  I need to watch some youtube videos explaining what is actually happening, but to my layman eyes it looks like a pretty decent amplification tool.  Am I doing anything particularly detrimental?


Started with this:

(http://i.imgur.com/DynlNig.png?1)

Added this compression:

(http://i.imgur.com/EMZxnYX.png?2)

Came out with this:

(http://i.imgur.com/i0OzifT.png?1)
Title: Re: Compression question: Is what I'm doing helpful or harmful?
Post by: anr on October 20, 2013, 04:56:28 AM
I think you're doing the right thing.  Read up on what compression is and try it out.  What you've done here LOOKS fine.  You think it SOUNDS fine, which is the ultimate test.   Always keep a copy of the original file. 
Title: Re: Compression question: Is what I'm doing helpful or harmful?
Post by: page on October 20, 2013, 12:17:40 PM
(IMHO) almost a half second attack = woof... I approach a half second as my release time on the final mix bus.

I guess a better question; what are you trying to achieve? There may be a much better way to do it.
Title: Re: Compression question: Is what I'm doing helpful or harmful?
Post by: achalsey on October 20, 2013, 12:47:12 PM
Yeah, I duplicated the original, added the compression to the copy, boosted the gain on the original to have the volume the same on both tracks and they sound identical to me.

Basically, I'm just trying to use it as an amplification tool.  I've only really used normalization in the past, but for shows with large dynamic ranges, I'm curious if correct use of compression (no necessarily what I did here) could help with a more "even" amplification as opposed to just boosting evenly across the board.
Title: Re: Compression question: Is what I'm doing helpful or harmful?
Post by: page on October 20, 2013, 01:17:49 PM
If I were in that boat, I'd try limiting (say, the top 4db after normalizing) before I did compression on a PA audience tape as the sound engineer has already run stuff through a compressor. I've found that lots of transients can be knocked out without adversely affecting the sound of a tape if you're careful in your settings. After that, I'd look at a compression ratio of 1.5:1 or less with an attack that was less than 10ms and a release around a half second, maybe slightly longer. I shorten the release only for multi-track mixing where I'm fiddling with a specific instrument, otherwise the half second (give or take 100ms in either direction) has been reliably well done. Trolling GS, it looks like most mastering folks who are applying 2bus compression favor a similar value.
Title: Re: Compression question: Is what I'm doing helpful or harmful?
Post by: achalsey on October 20, 2013, 01:29:49 PM
Okay, thanks for tips Page!  I have been messing around with a limiter the past few shows I've done as well.
Title: Re: Compression question: Is what I'm doing helpful or harmful?
Post by: page on October 20, 2013, 01:45:06 PM
It's sort of futzy, how much you do and what settings are really dependent upon the material. Some shows I'm ok with lots of limiting because it's random drum transients. Others I keep to just the top db or 2 as it's actual content.
Title: Re: Compression question: Is what I'm doing helpful or harmful?
Post by: kirk97132 on October 20, 2013, 02:37:18 PM
In general keep your ratios down too or it starts to "breathe" keep them under 3:1.  There are exceptions but that is a longer much more involed and detailed discussion.