How a Piano Is Tuned Today: Strobe Tuners, Tuning Computers and iPad Apps Compared

Piano owners often ask me whether a piano is tuned by ear or by a machine. The honest answer is both. Almost every professional now uses some electronic aid to set pitch precisely, but the machine only tells you how far a note is from its target. The craft is still in the hands and the ear: the lever technique that sets a tuning pin so it holds, the way three strings are brought into a clean unison, and the judgement that keeps the whole instrument stable for months. This is a plain guide to the tools a tuner might use, from spinning strobes to iPad apps, what each is good at, and what they cost in 2026.

The one problem every tool solves: inharmonicity

A piano string is stiff, so its overtones sit slightly sharp of the pure mathematical harmonics, and more so on the short strings of a small piano. Because of this, a piano tuned to textbook frequencies actually sounds sour. So a tuner widens the tuning, sharpening the top and flattening the bottom, until the overtones the ear compares line up and the octaves ring clean. This is called stretch, and the right amount is different for every piano. Every tool below exists to help measure and hit that stretch accurately. There is a fuller explanation on my page about why a piano will not stay in tune.

iPad and iPhone apps: the modern mainstream

A tablet running a good tuning app is what most working tuners reach for today. The best ones listen to a few notes, measure that specific piano, build a custom stretch curve, then guide you note by note.

• TuneLab and Verituner are the two most widely used by professionals, both around €300 as a one-time app.
• PianoMeter is an excellent budget entry, free to try and roughly €30 to €60 for the paid tier.
• CyberTuner and Pianoscope Pro sit at the premium end, from about €150 a year up to €900, with concert-level features.
• There is even a free desktop option, the open-source Entropy Piano Tuner.

The advantages are that they are portable, inexpensive, always improving, and they calculate the stretch for you. The trade-off is that a phone or tablet is a general device, and you are trusting the app's calculated curve.

Dedicated tuning computers: the Jahn CTS

Before apps took over, the German-made Jahn CTS series was the classic purpose-built tuning computer: a handheld box with a numeric and strobe-style display, built-in historical temperaments, and, on the higher models, the ability to measure a piano's inharmonicity, store a custom curve, and reproduce a whole tuning on your next visit. The range runs from the compact CTS-5-C up to the flagship CTS-32-C.

I contacted Alfred Jahn GmbH directly while researching this article. They still manufacture the whole CTS range in Germany, all four models are available, current prices are shown once you register for their trade webshop, and delivery to Ireland takes about three days. One note for the trade: Meyne, a long-standing German parts house that also carried this range, closed its doors at the end of July 2026 after 40 years, so the maker's own webshop and general music retailers are now the route to these.

Mechanical strobe tuners: the Peterson AutoStrobe

The traditional professional standard, and still made in the USA. A motor spins a patterned disc while the note you play flashes a light across it. When the string is in tune the pattern stands still, and if it drifts you can see instantly which way and by how much, to about a tenth of a cent. Because several bands show different partials at once, you literally watch the piano's inharmonicity rather than trusting an algorithm.

The piano-capable models are the AutoStrobe 490-ST and the 590, roughly €1,290 to €1,330 once shipping and Irish VAT are added. The plain 490 has no stretch tables, so it is not the piano choice. The trade-off is that it is a desk unit and it rewards an experienced eye.

Handheld virtual strobe: the StroboPlus HDC

A pocket device that draws a strobe-style moving band on a screen, with built-in piano presets, for about €200 landed. It gives you the intuitive strobe feel with modern convenience, and it is the affordable way into strobe tuning, though a small single band shows less than a full mechanical disc.

At a glance

Prices are approximate for 2026 and are shown before shipping and VAT where relevant.

So which is best?

There is no single winner, because the tool matters far less than the person holding the lever. A skilled tuner gets a beautiful result from a €300 app, and a beginner will not get a good tuning from a €1,300 strobe. Most professionals today do brilliantly with TuneLab or Verituner on an iPad, strobe devotees love the Peterson AutoStrobe for the way it shows the partials, and the Jahn CTS remains a solid dedicated box for those who prefer a purpose-built unit over a tablet.

What matters more than the machine

Whatever a tuner points at your piano, the things that decide whether the tuning sounds good and lasts are the hammer technique that seats each pin, clean unisons across all three strings of a note, and the experience to read your particular instrument and room. That is the part you are really paying for. If your piano is due, you can see typical costs or book a tuning in Dublin.