TUNE88

Park on a note and play an interval. The detector listens to the coincident partials of both strings, works out which interval you played, and measures the beat between them. When the reading settles it stamps LOCKED and logs the rate, the step percentage over the interval before it, and the solved reference.

Intervals: thirds, fourths, fifths, sixths, octaves, tenths, twelfths, seventeenths and nineteenths, fourteen checks in all, with wide/narrow readings on the tenths and seventeenths. The pills above the roll choose the family; ACTIVE INTERVALS in the menu chooses which pills show.

Best practice: a clean single strike and a second of ring beats hammering the keys. It reads beat speeds better on muted strings. Two strings sounding where you wanted one puts a second, unrelated beat into the same window, and the detector has to pick between them; a wedge in the unison removes the question. Unmuted still works in the midrange on a piano whose unisons are close, and it is the faster way to work. But if a reading will not settle, mute it before you blame it. In GUIDE mode the detector restricts itself to the current step's interval, so a stray note cannot log a false row.

Every note reads zero at its own solved target, so tuning is always the same job: bring the number to nothing. METER is one line against a strobe; the stripes drift sharp-left, flat-right, and stop dead only when you are truly on pitch. GRAPH is the live spectrum: each sounding string is its own peak, the solid line is the target, and the scale magnifies the last few cents where the work happens. TARGET AS CURVE OFFSET in Display shows each note's cents against ET instead of zero-centred, if you prefer the classic view.

LOCK: a struck note is never one pitch. It jumps as the hammer leaves, falls away through the decay, and settles differently again once the string quietens, so a live number is always moving and you are left guessing which part of it to believe. LOCK grades the strike and holds the one value worth reading until you strike again. You set the pin against a still number, hit the note, and it relatches. That is what makes the last half cent settable rather than approximate. FAST puts the live reading back for rough work and pitch raising, where you want to watch the note move.

Unisons: switch on the MULTI-PARTIAL STROBE and the stripe divides into one band per partial (left), in either view. Each band drifts at its own partial's beat and settles still when that partial is clean, so a finished unison is a screen that has stopped moving. No labels to read, just motion or none. Your hands still set the unison; this only shows you what they did.

Tap a note to arm it, strike until it goes green, move on. Twelve notes covers the whole piano, about two minutes of work; the six temperament notes alone cover the middle for a quick job. Each strike is graded against the physics of real scale designs: implausible reads go yellow instead of silently bending the curve, and the SWAP button substitutes a neighbour when a string is dead or wildly false. A wedge mute is all it takes when an open unison will not read cleanly, and muted reads count.

Best practice: firm, even strikes, and let each ring. If a note sits yellow, tap it again to clear its pool and re-strike. Any note can be spot re-measured later without touching the rest.

From your measurement the app solves one consistent set of pitches for the whole piano, and every beat target and cents target on every screen derives from that single solution. The rules behind it were reverse-engineered from recordings of master tuners at work: from each session we extracted the tuning the master left and the inharmonicity of the piano he left it on, then derived the relationship between the two. Solved on those same pianos, the engine lands within 0.8 of a cent through F3 to C6.

Among the tuners in that corpus: a Korea Master Craftsman No. 1, a Chopin Competition concert tuner who tuned for Richter and Michelangeli, a Steinway-trained technician recorded across three different instruments, and a Steinway technician. Seven recorded sessions between them, close to eight hours of tuning, note by note. They do not all agree with each other, and where they disagree is where the stretch styles came from.

What the style actually moves. The stretch style is a treble control, and it is worth being blunt about that. On a measured upright it changes the bass by nothing at all, the bearing F3–A4 by under a third of a cent, the treble by a few cents, and the top octave by tens of cents. If you want to move the middle of the piano, that is the temperament, not the style. Classic is the middle of master practice and the default; Mellow and Concert are its warm and bright edges; the pure schools (octaves, 12ths, 19ths, double octaves) follow each school's beatless rule; custom blends solve exactly like the built-ins.

Temperaments work the same way: equal or historical, the offsets are solved into your piano's curve, not pasted from a chart. Your own custom temperaments slot in beside the book.

The overpull ladder is calculated from the measure before you strike a note: a dashed target line stands above the curve on every note, and a dashed overpull curve rides over the stretch strip so you can see the whole raise in advance. Strike unmuted; the flat unison reads as one pack and you pull one string at a time onto the target. The ONE-STRING OVERPULL option compensates for the strings you have not pulled yet, the fastest way through a big raise. Severe raises get a second, lighter pass; FINISH hands you straight to fine tuning.

Pick Defebaugh's F to F, Potter's bearing, or Bill Bremmer's Marpurg sequence and the GUIDE tab walks you through it step by step. Each step names the note to set and the checks that prove it, and the detector reads those check intervals live, so the evidence for every step is a measured beat speed, not a feeling. The star markers on the roll show the step's notes.

Past the temperament, the AURAL EXPANSION GUIDE in the menu is the whole-piano ladder: octaves up, twelfths and triples through the top, the bass by single octaves with the minor-third and minor-tenth checks. It is generated from the same solved curve the tuner screen is reading against, not a printed table sitting beside it, so if you change the stretch style or the temperament, the guide's checks change with it. Tune the whole piano by ear off the guide and you land on the app's curve; tune it with the app and it passes the guide's checks. They cannot disagree, because they are the same solution.

The training wing has four rooms: THEORY, eleven chapters from partials to temperament from first principles; EAR TRAINING, 20 levels where two beats play and you call the faster one, narrowing from ±60% to ±1.6%; a TEMPERAMENT SIM to hear intervals at chosen rates; and ON YOUR PIANO drills. The LISTEN toggle isolates the beating partials of whatever you play into your headphones, so the beats you are learning to hear get loud while you learn them.

Most of the school is free. Every theory page, the whole twenty-level ear-training ladder and the temperament simulator as far as THE WINDOW stay unlocked when the trial ends, on any install, forever. The rule is that anything which teaches you without your piano is free; the drills that listen to a real instrument across the whole compass are Pro, because they need the full detector rather than the free version's major thirds in A3–A4.

Every job saves as a file: client, make and model, notes, the full measurement, the logged intervals and the tuned-note progress. The LOAD TUNING list shows each piano's state at a glance, with search and newest-first sorting. Reopening a file rebuilds its exact curve, so the next visit to that piano starts where the last one ended, no re-measuring. The TUNING REPORT prints the temperament zone note by note with a quality score, client-ready; the diagnostic report is the deeper version for your own records.

Where your files actually live. Every tuning is its own file on your phone, in the Files app under On My iPhone → Tune88. That means three things. They are included in your iPhone's iCloud backup, so a lost or replaced phone does not cost you your customer history. You can AirDrop one to another device or to a colleague and they open it straight into their own copy of the app. And you can copy the whole folder anywhere you like as an archive. Nothing is locked in an account, because there is no account.