Having recently transferred an Edison "80 rpm" disc (one of his long-players),
I can tell you the 80 rpm speed may not be exactly right. A good "ear" and an
accurate pitch reference for tuning are really necessary, regardless of how
the pitch correction is implemented.
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> Date: Mon, 27 Apr 2015 20:14:03 -0400
> From: "Richard L. Hess" <[log in to unmask]>
> Subject: Re: Here's a tough one - maybe
> On 2015-04-27 8:45 PM, Paul Stamler wrote:
>> On 4/27/2015 2:05 PM, John Haley wrote:
>>> Turntables from the 78 era are usually nightmares
>>> for rumble, instability, etc.
>> A big amen to that. Incidentally, a disc meant to play at 80rpm will, if
>> played at 78.25rpm (nominal "78" speed) come out with every frequency at
>> 0.978125 x what was intended.
>> Sincea note that's a semitone flat is 0.9439 x the intended frequency,
>> that means that an 80rpm disc played at 78.25rpm will be less than a
>> semitone off. Still worth correcting. If the frequencies are all
>> multiplied by 80/78.125 = 1.0223642, they'll come out right.