Good vibrations

Renowned British turntable manufacturer Rega once defined a turntable as a vibration-measuring machine; that definition became the title of a coffee table book tracing the company’s history and design philosophy.

- BY MICHAEL TREI

To me that title perfectly captures what a turntable does: measure the microscopic undulations pressed into the record groove by using a phono cartridge to convert them into an electrical signal that feeds the rest of the system. The more accurately the turntable can measure those tiny squiggles, the better the turntable is. It’s really that simple.

I always get a chuckle when someone tries to tell me that a turntable's sole requirement is to rotate at a steady 33 ⅓rpm—that assuming that's achieved, every turntable sounds the same. While rotational speed accuracy and consistency is a critical factor for reading those grooves correctly, it is just one of several factors that affect the signal that ends up traveling down the tonearm wire.

The little squiggles pressed into the groove walls of your record are a physical representation of the audio signal. They range in size from deflections you can easily see with the naked eye to the truly infinitesimal. Look carefully at a copy of Tchaikovsky's 1812 Overture on Telarc (DG-10041)—specifically at the cannon shots near the end of the piece: You can practically measure the size of those squiggles with a ruler. Playing those cannons will tax the tracking abilities of most cartridges to the point where sometimes I fear for the safety of the stylus and cantilever.

But while the loud stuff can be fun and impressive for showing off your system, it really tells you nothing about what is happening down at the other end of the dynamic scale, which is where the differences between a good turntable and a truly great one manifest.