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Again,let me bring up the Deutsce Gramophon microgroove 78s rom 1950,'51 or so. Anybody care to discuss these ?

                                        Roger



--- On Wed, 10/14/09, George Brock-Nannestad <[log in to unmask]> wrote:

From: George Brock-Nannestad <[log in to unmask]>
Subject: Re: [ARSCLIST] late date 78
To: [log in to unmask]
Date: Wednesday, October 14, 2009, 6:37 PM

From: Patent Tactics, George Brock-Nannestad

Hello, Milan Milovanovic asked:
> 
> Speaking of micro versus wider grooves, would wider grooved cut record be 
> more resistant to micro scratches and easier to get clean from dust etc. 
> than "microgrooved" LP record?
> 
> Also, would 78 rpm speed be more suitable for recording/reproducing 
> especially at the last 1/5 of disc with no groove distortion added in this
> area (often connected to ordinary 33 rpm records)?
> 

> > Hello,
> >
> > Mike Biel wrote:
> >
> >> Theoretically the best sound at 78 would be with a microgroove size
> >> groove since it would be capable of higher frequency response than a
> >> wide groove, or a microgroove at slower speeds.
> >
> >
> > ----- now, I am speculating why this should be so. I do not understand why
> > a
> > microgroove should give a higher frequency response than a NORMAL groove.
> > It
> > has to do with the maximum acceleration of the tip and the ability of the
> > tip
> > to trace precisely the groove shape. If the smaller radius of an 
> > elliptical
> > stylus (or the radius of the edge in a line contact stylus) is able to 
> > trace
> > without error a curve in one flank of the groove, it does not matter
> where
> > the other flank of the groove is.
> >
> > If microgroove is associated with a higher groove pitch (which would
> mean
> > well above 200 grooves per inch), then the maximum amplitude would be 
> > reduced
> > compared to the ca. 100 grooves per inch in a traditional 78 rpm record.
> > If
> > we maintain the 100 grooves per inch but reduce the groove width and 
> > depth,
> > we would have more land to use, and the modulation could be higher,
> which
> > would give a low frequency advantage. That is the rationale behind disco
> > singles (albeit at 45 rpm). And all of this without variable groove pitch.
> > If
> > that is used, then we are even better of, bass-wise.
> >
> > Kind regards,
> >
> >
> > George