The best iOS Tuner apps for Learning to Sing or Whistle in Tune
TLDR; CarlTune & Cleartune
There are many different tuner apps on the iOS app store.
However, most of them are not suitable for learning to sing or whistle in tune.
Most of them are OK for tuning a guitar. But using a tuner app to tune a guitar is totally different to using a tuner app to tune your singing or whistling.
When you tune a guitar, you are tuning the notes before you do the performance.
When you use a tuner to learn to sing or whistle in tune, you are using the tuner during the performance. So you are doing two things at once:
Performing, ie singing or whistling
Reading a pitch value display to see if your performance is in tune.
When tuning a guitar, you correct any wrong notes before you start doing any performance.
When singing or whistling with a tuner, you have to correct any wrong notes as you sing or whistle them, hopefully in a manner that does note spoil the musicality of the tune.
To distinguish between these two use-cases of “before” and “during”, I will use the term Live Performance Tuning to describe the latter, which is the thing that we are interested in here.
Everything discussed here could equally apply to practising an instrument like the violin or trombone, where each note has to be played correctly and in-tune by the player. However I do not (yet) have any experience playing such an instrument – the following analysis is based just on my own personal experience of practising singing and whistling using tuning apps.
Required and Desired Features of a Live Performance Tuner App
The first thing to know about live performance tuning is that you can only be watching a single pitch value display. Many tuner apps have multiple displays, including the two apps that I recommend. But when you are live performance tuning, you will only be looking at one display. Unless you perform your tune very, very, very slowly, you simply do not have enough time to switch attention from one display to another and then back again while simultaneously making the effort to sing or whistle the correct pitch values.
So any required or desired features have to be within the one display that you will be looking at.
For both CarlTune and Cleartune, that preferred display is the main circular display that each app has.
Features Required or Desired
Continuity: If the pitch value changes smoothly, the display should move smoothly. It should not jump just because you are now closer to a different note on the scale.
Display Range: The maximum possible range of pitch values should be visible in the display. Ideally this should be an octave.
Reliable Detection: The app should reliably detect the pitch value of the voice, whistle or instrument sound that you are tuning.
Timely Detection: The app should detect the pitch value of the sound being tuned as quickly as possible. There is no reason why detection should have any discernible lag.
Damping: There should be an adjustable damping option. Especially for voice, some degree of random variation is inevitable, and it is easier to learn against a damped pitch value display than against a shaky “raw” undamped display.
Colour-based “Hit” display: The pitch display should give some direct indication via a colour change that the singer is within a certain range of the nearest pitch value in the scale. 10 cents is a reasonable value to start with. (Note – a cent is 1/100 of a semitone.)
Gradations: The pitch display should show detailed gradations. 10 cent gradations is probably ideal. (There’s a limit to how detailed the gradations can be if the display is showing a full 12 semitones.)
No History: There should be no display of pitch value history. Quite a few tuning apps have this option, including those advertised as helping the user to learn to sing. But in practice, I find that seeing “what just happened” is a distraction from seeing “what is happening right now”. (It is technically true that damping is a very limited form of including “what just happened” in the display, so I would qualify the “No History” rule by saying that displaying a running average over a very limited time window is OK, but anything more than that is distracting.)
Most guitar tuner apps fail on one or more of these criteria, because they are things that don’t actually matter when you are tuning a guitar:
Most chromatic tuner apps show just the nearest note and the 50 cents either side, which is all you need when you are tuning guitar strings, and it doesn’t matter too much that the display jumps every time you move more than 50 cents from the current nearest note.
Detecting the pitch value of a guitar note (or almost any other instrument note) is much easier than detecting human voice pitch, because a human voice can have much more stuff going on.
Damping doesn’t matter for a guitar tuner, because the guitar note will hold steady, whether it is out-of-tune or in tune.
Most guitar tuners do show gradations of just 1 cent, because they are not required to show a range any larger than 100 cents.
Evaluating CarlTune & Cleartune
The main display for CarlTune consists of a needle moving around a fixed circular dial representing a full octave. The main dial shows the 12 notes of the chromatic scale, but it does not show any finer gradations. The needle changes to a different colour when the pitch value is within the “Hit Range”, which can be specified to be anywhere from 0 cents to 10 cents.
CarlTune actually has 4 other displays, including note name, note on staff, note on keyboard and a -50 to +50 cents display. As mentioned above, none of these additional displays is useful when you are live performance tuning, because you have to be continuously looking at the main display.
CarlTune does not have any damping options. The default seems to be fairly similar to ClearTune’s 0 option as described below.
Cleartune displays part of a moving circular dial moving under a fixed needle. The dial shows the notes in the chromatic scale, and also 10 cent gradations. The needle changes to a green colour when the pitch value is within 3 cents of a note in the scale. The portion of the scale that is displayed depends on the size of the device and whether it is in landscape or portrait mode. On my iPhone SE in portrait mode, it shows 1.1 semitones either side of the centre value, which is not a whole lot, but is still reasonably useful.
ClearTune also has a separate linear -25 to +25 cents display, with a moving needle and the current nearest scale note shown as 0 in the centre. (As mentioned above, any additional display is not directly useful when live performance tuning.)
ClearTune has 3 different damping options, labelled as 0, I and II. For singing and whistling practice, I generally prefer I or II – 0 is too shaky to be useful.
The Ideal Live Performance Tuner
Based on my criteria, CarlTune and Cleartune are the only apps I have found to be useful for live performance tuning. However neither of them is ideal – which means there is room for either of these apps to improve. (Or someone else could make a dedicated live performance tuning app – but they would have to match the existing reliability and timeliness of pitch detection that CarlTune and Cleartune already have.)
In particular:
Cleartune does not have a full octave display range. The biggest I can currently get is a 7 semitone range in landscape mode on my iPad Pro.
CarlTune does not show any additional gradations in the main display (not even on an iPad).
Cleartune has only the non-adjustable “Hit Range” display of +/- 3 cents. For beginning learning to sing or whistle, 10 cents is a better choice. 3 cents is pretty tight even for a professional.
CarlTune does not have any damping option. The default option is fairly shaky when practising singing (at least it is for me).