[linux-audio-user] LADSPA SC2, SC3 Compressors and Sidechain

Russell Hanaghan hanaghan at starband.net
Mon Feb 16 19:58:00 EST 2004

On Sat, 2004-02-14 at 12:20, Joern Nettingsmeier wrote:
> Russell Hanaghan wrote:
> > On Sat, 2004-02-14 at 03:52, Steve Harris wrote:
> > 
> >>On Fri, Feb 13, 2004 at 11:09:10PM -0800, Russell Hanaghan wrote:
> >>
> >>>On Thu, 2004-02-12 at 22:56, Russell Hanaghan wrote:
> >>>
> >>>>I could not get any noticeable function trying the sidechain inputs of
> >>>>these (I forget if it was specifically SC2 or 3 or 4 but could see the
> >>>>inputs in Jack-Rack)
> >>>>
> >>>>I ran jack from Qjackctl, Ardour and jack-rack. Inserted SC3 into
> >>>>jack-rack. All routing was done from Qjackctl "Connect" interface. Tried
> >>>>every way to Sunday and could not get any effect except "makeup gain".
> >>>>Then I tried just patching SC2 then SC3, etc as inserts direct into an
> >>>>audio channel in Ardour for straight compression. Could not get them to
> >>>>do any standard compressing either.
> >>>>
> >>>>Any thoughts or illumination on these compressors would be great. I
> >>>>particularly want to run a "de essing" of sorts on a single mike imput.
> >>>>Is it possible with these plugs??
> >>>>
> >>>>Thanks
> >>>
> >>>No takers??
> >>
> >>Sorry, must have missed it first time tound. They do work (SC4 is used in
> >>JAMin), try setting low attach and decay times, winding the threshold right
> >>down the ratio right up and the knee to the middle and the peak/rms to
> >>peak.
> >>
> >>If your audio is comming in at quite a low level you may not hear anything
> >>- this is a thinko on my part, analogue compressors expect signals > 0dB,
> >>but in digital systems this is unusual, so the range of the threshold is a
> >>bit narrow. A future release will have a lower min range.
> >>
> >>- Steve
> > 
> > 
> > Thnx Steve..
> > 
> > What about the side chain inputs...Any info on how to use them as I
> > described? Like as de essing with pushed freqs from a seperate eq?
> i have not used scX's sidechains yet, but there is a quite nice 
> dedicated de-esser in the new TAP LADSPA package. it has some 
> problems at some settings (peaking setting did not work for me, but 
> low-pass did), but can be made to work rather nicely if you choose 
> the setting carefully.
> http://tap-plugins.sourceforge.net/

Tried this out...

Jack-rack complains that it's not setup for realtime operation. It does
work but it's very clippy. Also seems to create lots of crackles and
pops. Shame, because this is almost like an all-in-one sidechain comp
and eq combo. If the response could be smoothed out some and the plug
made to work effectively in realtime mode it could be very useful.

The TAP-eq is smoothe! Also like the stereo version of Gverb.
> regards,
> jörn

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