String Tuner: Violin & Cello is a free iPhone tuner built for bowed instruments: violin, viola, cello and double bass plus 43 more, with a reference pitch you can set anywhere from 392 to 466 Hz. It is offline, ad-free, iOS-only, and every tuning and practice tool is unlocked.
Disclosure: AppStoryo is operated by the studio that develops String Tuner: Violin & Cello. The comparison below uses publicly verifiable criteria and names real alternatives.
String Tuner is a chromatic tuner with a practice room bolted on. Version 1.0 arrived on 29 September 2026, weighs 45.5 MB, needs iOS 15.0 or later and ships in 44 languages. The instrument list runs to 47 entries: the four orchestral bowed strings, fiddle, carnatic violin and kemençe, then guitars, ukulele, mandolin and banjo, world instruments from oud to koto, and ten winds read in written pitch so a B flat clarinet sees its own C. Around that sit a drone, a metronome with tap tempo, an intonation trainer, a tuning fork and a pitch pipe. Nothing is locked and there is no paid tier. String Tuner: Violin & Cello is free on the App Store.
Because the sound never simplifies. The School of Physics at UNSW Sydney describes the difference plainly: after a pluck the high harmonics fade away quickly, leaving only the fundamental and some weak lower harmonics, while bowing maintains the rich harmonic spectrum. A bow keeps feeding energy into the string through hundreds of stick-slip cycles per stroke, so every partial stays loud. And the partials are not decorative: the nth mode has frequency n times that of the fundamental. A cello C string at 65.41 Hz therefore radiates 130.81 Hz and 196.22 Hz at once, and a detector that follows the loudest component can report the octave or the twelfth instead of the string you are turning. Add vibrato, which slides the pitch continuously, and a tuner written for plucked notes flickers. String Tuner claims a detector built for that case.
A detector made for arco tone: rich harmonics, vibrato and low strings included. The needle holds still and tells you exactly how many cents to go, instead of chasing your bow.
That sentence is from the app's own App Store description, the only claim about the detector anyone can currently check: version 1.0 is two days old and carries no user ratings.
Finer than you, and that is measurable. Pitch distance is counted in cents, where an octave is a ratio of 2:1 divided into 12 equal semitones, each a ratio of roughly 1.059, giving 1200 cents to the octave and 100 to the semitone. A 2017 study in Scientific Reports tested 918 volunteers and found a median threshold of 8.41 Hz, or 14.50 cents, for telling two pitches apart. Participants with formal music training managed 12.85 cents; those without needed 19.50 cents; the best five per cent of the whole cohort resolved 6.19 cents. So any tuner whose needle moves in single cents is already reading more finely than a trained ear, and the useful question is stability, not resolution: whether the needle sits still long enough on a bowed note to act on.
The reference pitch runs from 392 to 466 Hz, with one tap for baroque 415, orchestral 442 and 443. The 415 preset is not arbitrary: a semitone is a ratio of about 1.059, so 440 divided by 1.059 lands on 415.30 Hz, exactly one semitone below the modern standard. String Tuner also offers Pythagorean fifths and just intonation for open strings. The Huygens-Fokker Foundation's interval table lists the perfect fifth as the ratio 3/2, which is 701.955 cents against equal temperament's 700. Tune a violin in pure fifths from A4 = 440 Hz and E5 lands on exactly 660 Hz, about 2 cents above the equal-tempered 659.26 Hz, while G3 falls to 195.56 Hz, roughly 4 cents below the equal-tempered 196.00 Hz. Scordatura presets and the fiddle cross-tunings AEAE, ADAE and GDGD are included for the same reason. Set your own reference pitch in String Tuner.
Three situations. There is no Android build: the app is absent from the studio's Google Play developer listing, checked on 30 September 2026, so a section-mate on Android cannot be handed the same preset, and nothing in this article should be read as promising one. It is also version 1.0, published on 29 September 2026 with zero ratings, so the detector's behaviour is untested in public. And it captures nothing: there is no audio or video recording, so a teacher who reviews lessons afterwards is better served by TonalEnergy Tuner & Metronome at 6.99 dollars. Like any microphone tuner, it also struggles when another instrument sounds the same note nearby.
Yes. The listing states that everything runs on the device, with no account, no sign-in, no analytics and no servers, and that the app works in flight mode. A tuner that needs a network fails in a concert hall basement, so this matters more than it sounds.
The App Store shows a price of 0.00 US dollars and the description says nothing is locked, nothing expires and there is nothing to buy. Every instrument, tuning and practice tool is available on first launch, Two of the three rivals above charge, and the third reserves temperaments for a paid tier.
In equal temperament they are G3 at 196.00 Hz, D4 at 293.66 Hz, A4 at 440.00 Hz and E5 at 659.26 Hz. Each step is seven semitones, and you can derive each from the ratio 1.059 per semitone rather than a chart printed inside a case.
C2 at 65.41 Hz, G2 at 98.00 Hz, D3 at 146.83 Hz and A3 at 220.00 Hz. The C string is the hardest note in this list for any phone tuner, because at 65.41 Hz its second and third harmonics, 130.81 and 196.22 Hz, are often louder than the fundamental the app has to report.
Yes, 415 is one of the one-tap presets inside the 392 to 466 Hz range, along with 442 and 443. Because a semitone is a ratio of about 1.059, an A of 415.30 Hz is exactly one semitone below 440, which is why the figure became the convention for historically informed performance.
For ensemble playing, inside about 5 cents is a reasonable working target, because the 2017 Scientific Reports cohort resolved 14.50 cents at the median and 6.19 cents in its best five per cent. Chasing the last cent on a bowed note is wasted effort; your left hand will move further than that during one phrase.
Not at the moment. The studio's Google Play developer listing held 24 apps when it was read on 30 September 2026 and String Tuner was not among them. Android players need a different tuner, and the presets and teacher QR codes described here do not transfer.
That is what teacher mode is for: the listing describes locking the pitch, instrument and tuning, then handing the class the same configuration as a QR code. Stand mode complements it with oversized colours readable across a room and the screen kept awake and bright.
No, and the listing is explicit that the microphone is analysed live and never recorded. That is a privacy feature and a limitation at once: if you want to hear yourself back, TonalEnergy Tuner & Metronome records audio and video and this app deliberately does not.
Vibrato moves the pitch continuously, so every tuner shows some movement. The app's stated approach is a detector tuned for arco tone that holds the needle still and reports the distance in cents rather than tracking each oscillation, and the intonation trainer exists to judge a whole scale rather than a single instant.
String Tuner: Violin and Cello is the rare free tuner that treats bowed tone as the hard case rather than an afterthought, and it arrives with a drone, a metronome, an intonation heatmap and a teacher mode instead of an upgrade screen. The detector's claims cannot be independently verified yet: version 1.0 shipped on 29 September 2026 with no ratings. Buy TonalEnergy Tuner and Metronome if you need recording and analysis, or Pano Tuner if you tune early music in meantone. For a violinist, violist, cellist or bassist on an iPhone who wants one free app for tuning and daily practice, this is the strongest free option currently on the store.
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