[LAU] upwards compression

[Q]

Fabio wrote:
> Em Sat, 25 Dec 2010 16:47:04 +0100
> Jörn Nettingsmeier <nettings at folkwang-hochschule.de> escreveu:
>>> how you do that? none of the compressors i checked has ability to
>>> use negative ratio.
>>> upwards compression means it elevates volumes below threshold
>>> instead of the "opposite"(lack of word) in normal compression
>> you can set up two busses, both fed from the signal you want to
>> up-compress. one is left as-is, and the other is set for compression
>> at the threshold below which you want the up-compression to set in.
>>
>> now you mix both buses to the same master. the effect is that at low
>> levels, both signal paths will be uncompressed and add up. at higher
>> levels, the compressed signal path is attenuated and adds less gain,
>> which is the effect you're after.
>>
> 
> wow, audio-production is math, too...lol
> 
> but man, this will result in a normal compression, only that the ratio
> will be lowered.
> 
> I mean, lets say we have 4 signals with values: 1 2 4 8
> threshold between 2 and 4 give for ex. this: 1 2 3 4
> now i add both an divide by 2: 1 2 3.5 6
> 

Compression reduces the dynamic range. Ordinary or "normal" compression 
does it by affecting the loudest signals, reducing them in level, 
upwards compression does it by boosting the volume of the quietest 
signals -- compressing from the bottom up. This parallel processing 
produces upwards compression as Joern expounded on my original statement.

You mention a negative ratio: are you perhaps thinking of upward expansion?

Q