Re: [ARSCLIST] Non-RIAA preamp

[Jerome Hartke <jhartke@xxxxxxxxxxxx>]

Upon recording, equalization modifies both frequency and phase; these are
interrelated. Upon playback, perfect de-equalization would precisely
introduce the opposite frequency and phase modifications. A good preamp
would closely approximate the ideal, correcting both frequency and phase.
Equalization schemes were built upon simple circuitry, and the interrelated
frequency-phase plots are rather simple and easy to reproduce with a few
resistors and capacitors.

Recording hall reverberations are a separate topic, and have been discussed
elsewhere.

Jerry
Media Sciences, Inc.

> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:ARSCLIST@xxxxxxx] On Behalf Of steven c
> Sent: Friday, September 08, 2006 9:51 PM
> To: ARSCLIST@xxxxxxxxxxxxxxxx
> Subject: Re: [ARSCLIST] Non-RIAA preamp
> 
> ----- Original Message -----
> From: "Konrad Strauss" <konrad.strauss@xxxxxxxxxxxxx>
> > on 9/8/06 11:06 AM, Jeff Brown at jeffbro@xxxxxxxxxxxxxx wrote:
> >
> > > But no one addressed the issue of the phase shift correction needed to
> > > compensate for the phase shift introduced by the original recording
> EQ.
> With
> > > an analog phono preamp the required playback phase correction is
> inherently
> > > applied,
> >
> > 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.
> >
> The "analog phone preamp"...which, one assumes, would have capacitances
> and inductances in its circuitry...would (or at least in theory should)
> induce phase shifts. To further confuse things, I suspect those phase
> shifts would be related to the frequencies involved in the sound signal
> being dealt with! However, since any listener is by definition a fixed
> distance (and thus a frequency-dependant number of wavelengths, including
> fractional quantities) from the sound source...and in an environment
> which is NOT free from echo/reverberation (also wavelength-dependent)...
> there are phase relations of ALL sorts to be considered!
> 
> Steven C. Barr