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

[Patrick Shirkey]

On Sat, September 25, 2010 10:48 am, fons at kokkinizita.net wrote:
> On Sat, Sep 25, 2010 at 10:07:46AM -0700, Patrick Shirkey wrote:
>
>> To clarify further, are you referring to the entire ui or specifically
>> to
>> the parametric eq ui which Jan designed? I think Jan would be the first
>> to
>> admit that he is not a dsp expert but was instead attempting to provide
>> a
>> user friendly interface for the specific plugin.
>
> The confusion continues :-)
>
> AFAIK Jamin does not have a parametric EQ. It uses an FFT-based
> method with a graphical interface that makes it look either like
> a combination of 'freehand' frequency response and parametric,
> or as a 30-band 'graphic EQ'. But it's the same algorithm in all
> cases, and it's not a plugin.
>
> If works by taking the FFT of the input, multiplying in the
> frequency domain by some precomputed values, and transforming
> back using an IFFT. This modifies the frequency response of
> course, but it is *not* a linear filter and produces side
> effects (modulation). Jamin minimises this by 1) windowing,
> which amounts to crossfading between processed blocks of
> samples, and 2) processing much more overlapping blocks than
> the minimum required to do crossfading (which would be 2).
>
> The proper way to implement a filter of this type (with a FR
> defined at all multiples of Fsamp / 1024) would be by using
> linear convolution rather than cyclic. But as said, this is
> not the right kind of filter anyway.
>

Just to clarify again, are you saying here that convolution will produce a
cleaner result than fft?

Or that the implementation of the fft algorithm in jamin is not the most
efficient method of doing the transform?




-- 
Patrick Shirkey
Boost Hardware Ltd.