6 Oct
2006
6 Oct
'06
5:25 a.m.
On Thu, Oct 05, 2006 at 08:14:35 +0200, David Olofson wrote:
On Thursday 05 October 2006 19:59, Paul Winkler
wrote:
So that would be a little iffy. SC4 only advertises that it goes down to
1.5ms, which gives something like 90 segments in the attack segment.
Looking at the code, the compressors use a pretty expensive linear -> dB
conversion routine (cubicly interpolated lookup table) to work out the
gain changes, maybe I could substitute a cheap approximation function.
I'll bet that analogue compressors didn't use accurace logarithmic
approximations. I'm not sure It'd be worth dropping the calcualtion period
below 2 though.
- Steve
On Thu, Oct 05, 2006 at 07:07:34PM +0200, Fons
Adriaensen wrote:
I don't know how fast it *actually* is, but FWIW, my old Behringer
compressor/limiter has a lowest attack setting of 0.1 ms, and a
lowest release setting of 50 ms. On Thu, Oct 05, 2006 at 05:12:20PM +0100, Steve
Harris wrote:
That is what, 90 microseconds at 44.1 kHz? I don't think there are
any analog compressors that react anywhere near that fast. Don't
worry about it :-) The SC* plugins do the same as TAP (calculate the
gain every 4
samples),
but I interpolate the gain values between each computation. The
attch/deacay times were slow enough in my testing that it was OK
to do
that.
It should be OK for all practical attack/release times. The only
penalty is 3 samples of delay on the gain change and maybe that's
to be avoided for a hard limiter. For a normal compressor it
should not matter.