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

On Sat, September 25, 2010 10:48 am, fons@email-addr-hidden 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.
>

I have to admit I didn't follow this part of the development process
closely enough but I will have a look to confirm.

> 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).
>

Hence jamin is already designed to minimise the negative effects on the
signal flow that are caused by the toolchain.

> 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.
>

So what you are saying is that the whole design is sub optimal? Can you
clarify this in terms of every genre of professionally oriented music or
is it more of an audiophile type of concern? Like preferring Bugatti to
Toyota?

I think the whole jamin team would agree with you that we started out with
the idea we were not the best people to make the software but that instead
we were attempting to resolve a missing component of the LAD toolset. In
that case we did the best with the knowledge and skills that we had.

Jamin was defined from the start as one way of handling the mastering
process. Not necessarily the best or suited to every type of recording. It
integrates the tools for that method into a single interface.
Gold/Platinum radio friendly rock/metal albums have been produced using
that method by the main "professional" contributors.

For those interested in using jamin as a part of their toolset it should
be kept that it has these artifacts Fons describes above. Considering that
you are compressing the audio as much as possible in order to get a radio
sound anyway these trade offs may not be much of a cause for concern.

-- 
Patrick Shirkey
Boost Hardware Ltd.
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