[LAU] [Sort of OT] Ringing in filters

Joel Roth joelz at pobox.com
Wed May 12 20:14:41 UTC 2010


On Wed, May 12, 2010 at 09:44:58PM +0200, Fons Adriaensen wrote:
> On Wed, May 12, 2010 at 11:30:11AM -0700, Ken Restivo wrote:
> 
> > So, are the artifacts caused by the compressors or the EQ?
> 
> The ones I referred to are caused by the FFT-based EQ.
> 
> > I didn't use the EQ on JAMIN at all, just the multiband
> > compressors and the final limiter.
> 
> I don't know if Jamin uses the FFT processing to implement
> the bandsplitting for the multiband compressor.
> 
> If it does then the artefacts of this type of processing
> will show up in the output. 
> 
> If it doesn't, then Jamin needs some type of bandsplitting
> fillters that add up to exactly the input if compressors
> are inactive. I doubt very much if these are implemented
> in Jamin.  
> 
> Ciao,
> 

Some time ago, Julien Claassen forwarded to me the
results of his exchange with Fons regarding reasonable defaults for
a three-band mastering network for Nama.

As Fons writes here, the sum of the bandsplitting filters
is unlikely to add up to the original signal, however
we did adopt what we believe to be a reasonable compromise,
with just a couple dB error.

I'm appending the default settings for the LADSPA effects
we are using. Each of the low/mid/high branches gets a compressor
and a spatialiser.

                +-- low --+
mix ----> eq ---+-- mid --+-- boost ---> output
                +-- high -+

You could create a similar network in Ardour or any other
sufficiently flexible software.

It might be worth experimenting with some A/B comparisons.
(Might be nice to have a program that can randomly cross
fade a couple signals with a beep indication. The listener does a
blind comparison, inputting his opinion at the keyboard.
Afterwards the program correlates the inputs with the 
signals.)

	eq: Parametric1 1 0 0 40 0.125 0 0 200 0.125 0 0 600 0.125 0 0 3300 0.125 0

	low_pass: lowpass_iir 106 2

	mid_pass: bandpass_iir 520 800 2

	high_pass: highpass_iir 1030 2

	compressor: sc4 0 3 16 0 1 3.25 0

	spatialiser: matrixSpatialiser 0

	limiter: tap_limiter 0 0      

Regards,

Joel

-- 
Joel Roth


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