Turntable tools: strobe disc, alignment and speed

Three utilities to tune up your turntable: a printable strobe disc, a cartridge alignment protractor and a platter speed test with the microphone.

Three free turntable tools in your browser: a printable strobe disc to check the platter speed, a cartridge alignment protractor (Baerwald, Löfgren, Stevenson) and a speed test that listens to a test record with your microphone.

Print at real size

The strobe disc and the protractor only work when printed at 100% (actual size) — turn off «fit to page» and check the printed circle against the size shown with a ruler.

And while you are at the deck: if you want the details of the record playing, with its release year, tracks and running time, you will find them in the album and discography finder.

Frequently asked questions

How does a strobe disc work?

Under mains-powered light that flickers at twice the mains frequency, marks spaced for the right speed appear frozen. If they drift forward the platter is fast, backward means slow. Use an old-style incandescent or non-dimmable bulb — many LEDs do not flicker and will not work.

Why does cartridge alignment matter?

A pivoting tonearm can only be perfectly tangent to the groove at two points (the null points). Aligning the cartridge to a proper geometry (Baerwald, Löfgren, Stevenson) minimises tracking distortion across the record. The protractor here lets you set it precisely.

How do I measure the platter speed?

Play a test record with a known tone (typically 3150 Hz) and let the tool listen with your microphone. If the platter runs fast the pitch rises, if slow it drops; the deviation in percent tells you exactly. No test record? Use the strobe disc instead.

Why must I print at 100%?

The strobe disc and the protractor only work at true physical size. In the print dialog choose «Actual size» / 100% and turn off «fit to page», then verify with a ruler against the size shown on the sheet.