On 27/09/03, [log in to unmask] wrote:
> When was the 15 degree cutting angle adopted?

The pickup cartridge makers started worrying about the distortion caused
by differences in cutting and playback angles around 1958. At that time,
every make of lathe had a different angle. The effect would be greater
with an elliptical stylus - these came on the market in 1964 IIRC.

Around 1964, the cartridge makers decided on 15 degrees as a reasonable
compromise. I'm not sure how long it took the makers of the cutting
equipment to confirm to this standard. Anyway, it was led by the
cartridge makers.

At the same time, RCA introduced the DynaGroove process, which was
supposed to introduce distortions into the groove to cancel out those
from the pickup geometry.

You might look for Proceedings of the Audio Engineering Society for
1964. You will also find numerous mentions of the topic in issues of The
Gramophone from August 1960 onward.

Don Cox
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