[78-L] Lacquer discs recorded at 80 rpm

[David Lennick]

On 1/4/2011 10:57 PM, Jeff Lichtman wrote:
>
>> I believe 80 was used for film playbacks because (a) 80 was easy to check for
>> speed (20 revs in 15 seconds) . . .
>>
>> dl
>
> Also, it is possible to use a strobe disk to calibrate to 80 RPM with
> either 60 CPS or 50 CPS, so the speed can be set exactly with either
> 60-cycle or 50-cycle current.
>
>

Further also, copies of playbacks made at 78RPM were given to performers to 
take home and learn for when they had to lip sync on the set. Once in a while 
somebody goofed and mixed up the speeds..

dl