[linux-audio-dev] Paper on dynamic range compression

[Steve Harris]

On Tue, Oct 17, 2006 at 01:53:40 +0100, John Rigg wrote:
> On Tue, Oct 17, 2006 at 11:56:20AM +0200, Fons Adriaensen wrote:
> > On Mon, Oct 16, 2006 at 07:48:35PM +0100, Dan Mills wrote:
> > > The gain control signal has energy right the way out
> > > to the band limit (and probably aliased around it),
> > > never mind what happens when that hits the multiplier!
> > 
> > The question is: how much of this HF energy is there ?
> > There shouldn't be much in a compressor with controlled
> > attack / release times. In that case it is always possible
> > to filter the control signal. In fact the obvious way to set
> > attack / release times is by such filtering !
> 
> True, but if the audio signal contains significant HF energy near
> the band limit, it doesn't take a very fast gain change to push it
> past that. Bear in mind that the ear is _very_ sensitive to aliasing
> artifacts, so `significant' can be a very small amount.

These are aliasing artifacts in the sidechain though, right? So they will
show up as modulations in the output, rather than directly audible
aliasing.

- Steve