Andrew Weatherhead wrote:What is azimuth computation?
Thanks,
Andrew
The pitch (tightness of spiral) of the groove cut into an LP master has to be varied to accommodate the varying sized of the groove required by the variations in signal. This spacing must be changed in advance to prepare a space for the groove about to be cut by the cutter head. This spacing is continuously variable, and the precise size of the space between grooves is determined by the azimuth computer.
Since the pitch has to be varied before the groove is cut, the computer must receive the audio one revolution before the cutter head. This is what the preview head on teh tape machine is for. When cutting from a machine without a preview head, the audio being cut into the disc is delayed by a digital delay line.
In this instance, the "analog" record is really being made from a digital signal. True all-analog cutting is becoming rare, but there are still places like Abbey Road that can do it without any fuss.
best,
-steve