StretchwiseMoving to Stretchwise from another tuning app
Stretchwise, the piano tuning app Tempore makes for iPhone and iPad, reads the files other tuning apps save, so you don't start each piano from nothing. It builds its own stretch curve from each piano's inharmonicity, so the most useful thing to bring over is your measurements. Another app's finished curve isn't imported. Stretchwise is on the App Store for iPhone and iPad.
Guides by app
- Switching from TuneLab: tuning files (.tun) bring inharmonicity, per-note offsets, the pitch offset and the three-part setting; temperament files (.tem) bring a temperament.
- Switching from Entropy Piano Tuner: Entropy files (.ept) bring the piano's name, concert pitch, and each recorded key's frequency and inharmonicity; CSV exports work too.
Where to import
Tap the piano bar at the top of the tuning screen. In the list of pianos, expand Import & backup and tap Import a tuning file…, then choose the file from Files, iCloud Drive or another storage app. Stretchwise names each new piano after the piano name inside the file, or after the file name if there isn't one. It selects the new piano when the import finishes. A TuneLab temperament (.tem) is the exception: it's applied to the piano that's selected, and no new piano is created.
From anything else: a table of notes
If your app or spreadsheet can save a table of notes, export it as CSV (comma, semicolon or tab separated) and import that. Each row needs:
- A note name, such as A4, Bb0 or C♯5, or a key number from 1 to 88.
- A pitch, as a frequency in Hz or as cents from equal temperament.
- Optionally, an inharmonicity value and a correction in cents.
Headings such as Note, Key, Hz, Frequency, Cents, Offset and Inharmonicity are recognised in any capitalisation. Files without headings work if the note comes first. Stretchwise skips rows more than 100 cents from their note. It also accepts inharmonicity shown ×1000, as TuneLab displays it, and converts it.
Not supported
Verituner, CyberTuner and PianoMeter files can't be imported. Their formats aren't published, so Stretchwise can't read them reliably. If one of these apps can export a table of notes, try importing that table.
After an import
The message tells you how many notes came in and whether anything was changed on the way, such as a stretch setting. It also lists up to three skipped lines with the reason, for example "more than 100 cents from the note". If nothing usable is found, nothing is imported.
To keep a copy of everything, use Back up all pianos… in the same section. Importing a backup on another device adds its pianos and replaces a piano only with a newer copy.
Before you rely on it
On TuneLab's seven published sample tunings, Stretchwise's curve comes within 0.9 to 1.7 cents rms of TuneLab's. That hasn't yet been confirmed on real pianos in the field. Check a few notes you know well the first time you tune a piano you've imported. If an import doesn't look right, email support@tempore.net. Please send the file only if you're happy to share it.
To try the maths before you switch, use the free piano tuning calculators.