Sound Quality (Vinyl)

This article is in a series pertaining to vinyl setup. For the other articles, see the top-level Vinyl Guide.

Objective Requirements Of Vinyl Playback

These statements are derived from psychoacoustics and electrical constraints that would be necessary to yield objectively optimal playback. These statements also form a concise summary of the audible issues with vinyl.

Pitch, wow and flutter

The playback speed of the turntable must be within 0.3% of 33 1/3 RPM at all times - or 5 cents. Variations of pitch must stay witin the 5-cent requirement and the modulating frequencies must not be audible.

Shockingly, this is extremely hard to achieve in belt-drive turntables for a number of very important reasons. Good direct drives are much better at pitch. (Bad direct drives are much worse at flutter.)

Low rumble

The low frequency noise (rumble) of the turntable must not impinge on program material, must not distort amplifier or speaker stages, and must not be audible.

Rumble is an intrinsic part of both the vinyl medium and the turntable. Often times, 5-10dB of the peak amplitude of a vinyl recording is contained in the rumble, and removing it can help increase the loudness for essentially free.

Frequency response

After RIAA equalization, the system must be able to reproduce frequencies from 20hz to 20khz to within 0.1dB of the source media.

0.1dB is close to the theoretical JND of amplitude for a single sinusoid; tolerances around 1dB in response are usually acceptable.

MM cartridges are well-known for boosting the high end if improperly loaded. Stylus or record wear will eliminate high frequencies. Rumble may make low frequency reproduction difficult.