Re: [ARSCLIST] Non-RIAA preamp

[Jeff Brown <jeffbro@xxxxxxxxxxxxxx>]

At 18:11 9/8/2006 -0400, you wrote:
> Hmm, interesting question. Does the analog phono preamp really correct for
> the phase shift caused by the cutting EQ or does it simply add even more
> phase shift? I would suspect the latter.
>
> --
> Konrad Strauss
> Director of Recording Arts
> Associate Professor of Music
> Jacobs School of Music
> Indiana University
> http://php.indiana.edu/~kstrauss
> Http://www.music.indiana.edu/department/audio/

Actually, it does both at once - but the phase shift added by the playback 
EQ (assuming
it's analog based) is, by the necessities of physics, exactly the inverse 
of the phase
shift introduced by the cutting EQ.

Phonograph recording and reproduction is an encode/decode process like Dolby.
The record manufacturing process purposely alters the program's frequency 
content
and those changes must be reversed upon playback for accurate 
reproduction.  The
cutting EQ, being analog based, _must_ introduce phase distortion as it does
it work in the frequency domain, and the playback EQ must unwind that 
distortion.

The original reason I sought comment was that I couldn't remember if garden 
variety
digital EQ is FIR or IIR.  If it's linear phase then those wishing to 
pursue the
'flat transfer then declick and re-EQ in software' technique owe it to 
themselves
to search out analog mimicing, phase bending EQ for phono reproduction.

So I'm still in the dark...are the common DAW software applications I 
mentioned built
with phase linear or phase bending equalizers?

Jeff