Hello to all members of this list,

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)?

Best wishes,


----- Original Message ----- 
From: "George Brock-Nannestad" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, October 08, 2009 6:52 PM
Subject: Re: [ARSCLIST] late date 78

> From: Patent Tactics, George Brock-Nannestad
> 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