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

From: Erik de Castro Lopo <mle+la@email-addr-hidden-nerd.com>
Date: Wed Oct 18 2006 - 00:16:58 EEST

Sorry, I'm coming into this late but .....

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!

You need a low pass filter on the control signal. It should
be somewhere well below 1kHz.
 
> Fixing this right means upsampling and adding a
> lowpass filter to the control loop, then downsampling
> again.

No it doesn't. You want to absolutely avoid fast changes in
the control signal because fast changes will modulate the
audio signal whcih is **not** desirable.

Erik

-- 
+-----------------------------------------------------------+
  Erik de Castro Lopo
+-----------------------------------------------------------+
"The reasonable man adapts himself to the world; the unreasonable
one persists to adapt the world to himself. Therefore all
progress depends on the unreasonable man."
  -- George Bernard Shaw (1856-1950)
Received on Wed Oct 18 04:15:01 2006

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