[LAU] Subject: Albums under a label recorded and/or mixed with Linux

fons at kokkinizita.net fons at kokkinizita.net
Wed Sep 29 12:44:35 UTC 2010

On Tue, Sep 28, 2010 at 06:44:09PM -0700, Patrick Shirkey wrote:
> On Tue, September 28, 2010 8:22 am, fons at kokkinizita.net wrote:
> > The implementation is fundamentally wrong. Just send a sine wave through
> > it, measure the result and ask yourself how a *filter* could ever produce
> > the broadband junk that this one is adding.
> Well if this is the case the implementation needs optimisation. That
> doesn't change the fundamental nature of the design choice.

Thas nothing to do with optimisation. The algorithm is wrong. It does
not do what you think it does and what the designers probably intended
it to do. The correct one is not much different, but differs in some
essential points.
> Don't you mean an optimised implementation of the filter?

No. I mean a correct implementation.

> > My concerns are not about the optimisation. For there isn't any. I repeat:
> > the implementation is fundamentally wrong, the method used does not only
> > filter but it also adds distortion, and most of the CPU power used by the
> > filter is used just to reduce the problems that result from this.
> >
> How can it be fundamentally wrong if all linear convolution operations can
> be expressed in the the transformed domain, and vice versa.

The fact that this *can* be done does not imply it *has* been done
correctly in this case. 
> If there is a problem it is not due to the fundamental nature of the
> linear filter.

I'd suggest you stop calling this a linear filter for it isn't.

> But I will query your analysis first because it may be that we are talking
> at cross purposes.
> IMO what you have identified is the potential for optimising the code.

No. Although a correct implementation would indeed use less CPU.

> This is definitely something that should be addressed if it indeed turns
> out you are correct in your analysis.
> Although I have strong reservations given that 3 different DSP engineers
> with qualitatively more experience than you can justify this design
> choice.

Then let them speak up. I've posted the technical arguments before and
nor you nor any of your experts has so far commented on them. And as to
my level of experience, I don't think you have any correct idea of that.

I've a nice collection of measurement results for Jamin, maybe I'll
publish a few of them and then your experts can try to explain them.



There are three of them, and Alleline.

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