Wow and Flutter!!

The criterion for frequency control of a recording is that the variation in frequency should not be observable to the ear, less than about 0.1 percent, which is less than the just noticeable difference in frequency over most of the audible frequency range. In order to eliminate both slow variations in pitch of the recording, called wow, and rapid variations, called flutter, the rotation speed of the record is carefully controlled by use of a heavy turntable and a precision motor.

Mechanical vibration of the turntable is isolated from the stylus needle to avoid rumble. The stylus itself is elliptical in shape, with the long axis of the ellipse oriented across the grooves. In order to achieve good compliance: that is, the ability of the stylus to track the groove and produce a linear signal, the tip of the stylus must be less than 0.025 mm, in size, generally made of industrial diamond. (ruby and sapphire have been known to used).

Home