Putting that 0.43% difference into perspective
77.92 RPM to 78.26 RPM = 8 cents (0.08 semitones)
Itıs the difference between A440 (77.92 RPM) and A442 (78.26 RPM).
Generally, most people cannot hear a 4 cent difference in tone (A440 vs
Perhaps 10% can hear an 8 cent difference (A440 vs A442).
Perhaps 40% can hear a 12 cent difference (A440 vs A443).
Generally, 100% can hear a 20 cent difference (A440 vs A445).
And ³Third-ed²! As John Haley said, "You have to deal with each record
as a thing [un]to itself."
~ Eric Jacobs
Eric Jacobs, Principal
The Audio Archive
1325 Howard Ave, #906, Burlingame, CA 94010
Tel: 408-221-2128 | [log in to unmask]
On 11/27/15, 6:37 AM, "Association for Recorded Sound Discussion List on
behalf of Ron" <[log in to unmask] on behalf of [log in to unmask]>
>But 78 rpm is actually 78.26 rpm, so why is he using 77.92 rpm? That's
>another 0.43% error.
>From: Association for Recorded Sound Discussion List
>[mailto:[log in to unmask]] On Behalf Of John Haley
>Sent: Thursday, November 26, 2015 9:47 PM
>To: [log in to unmask]
>Subject: Re: [ARSCLIST] 78rpm replay speeds & pitch
>Welcome to the wonderful world of 78's. That's just how it is. You have
>deal with each record as a thing to itself.
>On Nov 26, 2015 6:22 PM, "Andrew Hallifax" <[log in to unmask]>
>> I'm currently digitizing a series of Odeon 78 rpm discs of recordings
>> made in the early 1950s of one particular ensemble and I'm surprised
>> to find that while most discs render A=c440Hz when replayed at 78rpm
>> (77,92) certain exceptional examples deviate by 2% or more. Can anyone
>> suggest a likely cause? In some cases, discs ostensibly recorded on
>> the same day whose two sides bear consecutive matrices, even differ
>> from each other.
>> More puzzling still are a couple of discs where the pitch drops
>> gradually by around a quarter of a tone (roughly 3%) during playback
>> of the side. If anyone can suggest the likely or possible cause of
>> this, I'd be delighted to read about it.
>> Many thanks