Turntable tools: strobe disc, alignment and speed

A well set-up turntable gets five main things right (level, tracking force, anti-skate, cartridge alignment and speed), and you can check most of them at home with your phone and a printed sheet. Turntable calibration works best in that order, with an alignment protractor for the cartridge and, for the speed, your phone on the platter or a printable strobe disc. Tonearm height and azimuth matter too, but they call for other tools.

In the Speed tab, your phone lying on the platter runs a wow and flutter test in about half a minute and gives you the average speed too, using the same weighting as lab meters (AES6 and IEC 60386). Wow, the slow wobble, makes long notes waver, and flutter, the fast one, muddies them. Everything runs in your browser and nothing is uploaded.

How to use these turntable calibration tools

Go in this order, because alignment is checked with the stylus at its final tracking force and the level affects anti-skate.

1. Level the turntable. Open the Level tab, lay your phone on the stopped platter and turn the feet of the deck or the furniture until the dot is centered. Below 0.4° the tool calls it level.
2. Balance the tonearm and set the tracking force. With anti-skate at zero, move the counterweight until the arm floats, set the dial to zero and turn the counterweight to the grams your cartridge calls for. The Force tab gives you the middle of the range you enter, and a stylus scale is more accurate than the dial. Then set anti-skate to the same number. Our cartridge guide covers tracking force and anti-skate in more depth.
3. Align the cartridge. In the Alignment tab, pick a geometry (Baerwald if in doubt), type in the pivot-to-spindle distance or tap your turntable in the presets, and download the protractor as a PDF. Print it at 100%, check that the ruler measures 100 mm or 4 inches, and adjust the cartridge until the stylus lands on both null points with the body square to the lines.
4. Check the speed and the wow. Lay your phone on the platter, tap Start in the Speed tab and start the platter when you hear the beep. About half a minute later you have the average speed, the wow and the flutter. If the speed is off, confirm it with the strobe disc before touching the adjustment.
5. Listen to the end of a side. That's where alignment and anti-skate show most. If the last tracks distort or lean toward one channel, go back to steps 2 and 3.

How can I check the speed of my turntable?

Your phone on the platter gives you the average speed and the wow in about half a minute, the strobe disc confirms the average turntable speed against the mains, and a test record with the microphone measures everything with the stylus in the groove, record included. Each method sees something the others miss.

The W3C specification asks browsers to limit the gyroscope's precision to 0.1 degrees per second, to make it harder for a site to identify your phone by its sensor, and the tool checks whether your browser does. At 33⅓ RPM the platter turns 200 degrees per second, so each step is 0.05% of the speed. That's why the tool works out, for each phone, the figure below which it can't tell anything apart (from about 0.02% because of that step alone, a little more with each sensor's noise) and doesn't show any lower number. It's enough to catch wow you can hear, and comparing two high-end turntables takes a test record.

The strobe disc measures against the mains, because the lamp flashes twice per mains cycle, 120 times a second at 60 Hz. At 50 Hz, no whole number of marks gives an exact 45 RPM. The disc carries 133, which stand still at 45.11 RPM, 0.25% fast, the speed listed for 50 Hz countries in the record speed standard (IEC 60098).

What your wow and flutter reading means

According to Lindos Electronics, a maker of audio analyzers, 0.03% of weighted wow and flutter is practically inaudible and 0.08% is audible only in some conditions, although the exact threshold is debated. Around 0.1% a long piano note can waver in a reverberant room, and from 0.2%, the level of an ordinary cassette deck, you'd normally hear it. The UK magazine Hi-Fi News measured 0.02 to 0.08% on the seven manual turntables in our guide's table and 0.30% on the Pro-Ject Automat A1, a £369 automatic. The tool's colors are our own rule of thumb, green below 0.08%, amber up to 0.2% and red above.

The figure isn't the raw wobble. Meters weight it by how much it bothers the ear, with the peak at four wobbles per second, and the tool does the same with the AES6-2008 curve, which matches IEC 60386 and DIN 45507. It reports the peak by the 2-sigma method, the value exceeded 5% of the time, and it also splits wow, whatever wobbles below 4 Hz, from flutter, whatever wobbles above it. The big number is the peak of both bands together, and it comes out equal to or lower than their sum. To compare your deck with the Hi-Fi News table in our guide, use the line that adds wow and flutter, which sums the two bands the way the magazine reports them. Some meters split the bands at 6 Hz instead, so the separate wow and flutter figures may not match another meter's, although the overall figure is the same.

One revolution at 33⅓ takes 1.8 seconds, so a platter that wobbles once per revolution only counts for 31%. Our guide on whether an expensive turntable is worth it collects lab measurements of eight decks, so you can see where yours sits.

Common turntable calibration problems and how to fix them

Long notes waver even though the turntable is set up correctly

It's most likely the record. An off-center hole or a warped record makes the pitch wobble once per revolution, every 1.8 seconds at 33⅓, and the gyroscope can't see it because it measures the platter. To check, measure with your phone on the platter. If it reads steady (under 0.08%) and long notes still waver, the platter turns smoothly and the problem lies in the record or in something the phone can't see, such as stylus drag. Try another record, and if the wobble changes or goes away, it was the record. A warped record also makes the tonearm bob up and down, which you can spot by watching the headshell from the side while it plays.

If the phone reads 0.08% or more and most of the variation repeats once per revolution, look at the platter and its spindle, or at the subplatter on a belt-drive deck. If it's faster than that, look at the belt or the motor pulley. A rubber belt stretches and hardens over the years, and swapping it takes a few minutes. A test record with the microphone measures both things together, which is what you actually hear, so use it to check the end result.

The turntable runs slow or fast

Before you touch anything, check the speed selector, because a 45 played at 33⅓ sounds slow and dull. On belt-drive decks without a selector, such as the current Rega Planar 2 (you take the platter off) and many older Pro-Ject models, 45 means moving the belt to the larger step of the motor pulley. Then confirm the reading two ways, because the average speed from a phone depends on how its gyroscope is calibrated. If the strobe marks drift too, the turntable is off. According to Lindos, a good musical ear notices a pitch change of around 1%, although a fixed error of up to 3% usually goes unnoticed unless you have perfect pitch.

Direct-drive turntables usually have a pitch control, which you should set to zero or to its locked position. Many belt-drive decks have two trim pots, one per speed, on the motor board or under the platter, and the manual tells you where. If the speed is slow and also wavers, suspect the belt, since a stretched belt slips. To see whether the stylus drags the platter down, lay the strobe disc on the label of a record, play the first tracks and watch the marks as the stylus drops. If they drift back, the motor is short of torque or the belt is slipping.

The strobe marks never stand still, whatever the light

It's almost always the light. A strobe disc only works under light that flickers 120 times a second (100 in 50 Hz countries), such as an incandescent or halogen bulb, an old fluorescent tube with a magnetic ballast or the neon lamp many turntables have. Many LEDs don't flicker or do so unevenly, CFLs flicker tens of thousands of times a second and daylight doesn't flicker at all, so under them the marks blur or seem to move for no reason. If waving a pencil quickly under your light shows several separate copies of it, the light flickers, although that only helps if it flickers in step with the mains. An LED dimmed by pulse-width modulation flickers hundreds of times a second and won't do.

Make sure you picked 50 or 60 Hz for your country and that you're watching the ring for your speed. Put the disc on top of the mat, where the record goes, so you measure under normal conditions. And if you don't have a suitable light, measure with your phone in the Speed tab.

The cartridge lines up on one null point but not the other

That's almost always overhang, how far the stylus reaches past the spindle. If the cartridge sits square on the outer point but is twisted on the inner one, slide it forward or back in the headshell slots without turning it and try both points again. Once one lines up, twist it just enough to fix the other, and repeat until both line up.

If no position works, the protractor doesn't match your arm. Use the arc protractor with your actual pivot-to-spindle distance or a preset, such as 215 mm for the Technics SL-1200, 214.5 for the Audio-Technica AT-LP120X, 222 for the Rega RB220 and RB330 or 200 for the Pro-Ject Debut Carbon EVO and Debut EVO 2, and check that the stylus follows the red curve all the way. If your manual lists a different overhang, the maker used another geometry. The three the protractor offers, Baerwald, Löfgren B and Stevenson, are all valid. Baerwald spreads the distortion evenly and Stevenson cuts it at the end of the record. If the last tracks still distort with everything in place, suspect the stylus. Here's when to replace your turntable stylus, which depends on hours played rather than years.

You want to play 78 RPM records

You need a turntable with that speed, a 78 stylus and a speed check. An LP stylus is far too narrow for the wide groove of a shellac record. It rides the bottom of the groove, sounds poor and can damage both. A 78 stylus is spherical and much larger, such as Ortofon's 2M 78 with a 65 µm tip radius, against 18 µm for the 2M Mono. On top of that, 78s were cut with equalization curves that predate RIAA, so the tonal balance won't be quite right on a standard phono stage.

The strobe disc has a 78 ring, and the speed depends on the mains, 77.92 RPM at 50 Hz and 78.26 at 60 Hz. Both are standard, because the record players of the time ran on synchronous motors. With your phone, the Speed tab recognizes 78 on its own.

Did the cleaning work? Count the clicks

The Clicks tab listens to a stretch of the record with no music, before and after you clean it, and tells you how many clicks per minute there were and how many are left. How to wash a record without damaging it, which fluid to use and when a cleaning machine pays off is all in our guide on how to clean vinyl records.

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