On 10/4/2012 9:33 AM, Carl Pultz wrote:
> No one has mentioned the method that Andrew Rose applies: picking out the 50
> or 60Hz residual hum as a way to determine correct speed. Maybe that's been
> discussed before on the list. What's the consensus, if there is one?
I've done it, and as long as I kept the limitations of the method in
mind (60Hz wasn't always 60Hz) it's worked for me.
As for absolute pitch, or devices to detect variations from standard
pitch, those only work if the original was recorded at standard pitch.
For a jazz band -- especially one including a piano -- the odds of A-440
are pretty good. For a hillbilly or blues record, with no fixed-pitch
instruments (just fiddles, banjos or guitars) there's no guarantee.
Restoring the disc to concert pitch may be wrong.