[linux-audio-user] L1 and Q10 functional look-alikes?

Steve Harris S.W.Harris at ecs.soton.ac.uk
Wed Mar 30 14:29:34 EST 2005

On Wed, Mar 30, 2005 at 09:23:26 -0800, Brad Fuller wrote:
> >>Thanks Steve, I'm trying your "triple band parametric" and I can't get 
> >>the High-shelving freq to cut off fast enough. Perhaps I have the args 
> >>wrong:  I have the last args as: -70 5536 1, but it seems a gentle 
> >>decline. Am I doing something wrong? I'd like to have a brick at 5k. Can 
> >>that be done?
> >>   
> >>
> >
> >You can push up the 1 to a higher number, but it will effect the response
> >near the cuttoff, that may not matter to much for your situation.
> > 
> >
> I fooled around with the numbers, but I can't quite get what I want. 
> Maybe you can help me. what I want to do is have a brick-wall at 5500Hz 
> (with some adjustments below it, though I think I've got that with the 
> settings of the parametric bands.) Do you think your hi-shelf with a 
> gain of -70 and a slope of (input number here) is just too shallow of a 
> slope to this filter for a wall?

You wont be able to get a really serious brickwall with the highshelf, its
only 2nd order IIRC, you could try stacking a load of lowpass filters set
to the same cutoff, but you will get some sreious phase shift I think.

Brickwall filters, by thier very nature tend to have side effects or be
very CPU intensive.

- Steve

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