[78-L] Playback speeds - was: Re: Orville Knapp

[Chris Zwarg]

At 19:36 14.10.2008, you wrote:
>The $7 Victor record of the 'Sextet' from LUCIA has 'Speed 82' printed
>on the label.

...which reproduces it one half-tone (6%) sharp vs. the score and almost turns Caruso into a contralto (and Sembrich into Minnie Mouse!) - in fact this is one example of an early Victor recording running reasonably close to accurate pitch @ 78 rpm! 

Another problem making a playback speed decision even more difficult is the slight speed drift that many acoustic (and early-electric) sides display: At constant replay speed, the pitch at the end is different from the beginning because the recording lathe was underpowered. Some sides need to speed up by 1-2% towards the end (because of the lathe having a constant but insufficient torque, the "braking power" of the cutting stylus being higher at the outer edge of the disc), others need to slow down to get a musically accurate reproduction (because of gradually dropping torque due to failing batteries or a weak spring). Usually the difference is small enough not to bother the ordinary listener much, but it quickly becomes really nasty when you're trying to join up recordings stretching over several sides - at such a joint, even a difference as small as 0.5% is painfully audible.

>Undoubtedly Victor and Gramophone/EMI both had varispeed playback
>turntables in use by the time they began doing electrical overdubbings
>on Caruso and other records, so as to match the original recordings to
>what was being overdubbed.

The whole problem is caused by the fact that for the first 30 years or so, ALL recording lathes and turntables/gramophones were "varispeed", WITHOUT an ubiquitous reliable way of indicating the actual speed - stroboscopic discs are useless unless you have A/C light which wasn't universal at the time, and can be difficult to read depending on room lighting from other sources. When electric recording was introduced, A/C equipment was quickly banned from many studios because of hum interference; 1920's studio amps were usually batttery-powered to get "pure" D/C for the tubes, and stationary recording lathes were mostly still driven by falling weights (much like a cuckoo clock) as they had been since the very early 1900's; neither springs nor electric motors provided a constant torque like gravity did. Synchronous motors came into use rather late, and were not very practical for the semi-portable recording machines frequently used in Europe (and also for the now-legendary "field trips" to New Orleans and other places in the USA), as A/C cycles and voltage varied from country to country, if reliable A/C was available at all - e.g. parts of Germany still had 110 V D/C in the 1930's.

Almost every pre-WW2 gramophone, spring-driven or electric, had a "speed indicator" which however was rarely exact from the beginning, and quickly would have disadjusted with use due to the natural wear of the friction pad regulating the motor speed, so setting the pointer to "78" in no way guaranteed that the turntable really ran at that speed. "Speeds" found handwritten on old sleeves or on labels may well be just one listener's readings of the pointer setting on his gramophone, with no exact correspondence to the actual rpm - I suspect this might also be how Victor and HMV came to the occasionally very off-the-mark speed indications on some of their records!

Chris Zwarg