HandpanTuner user manual

This manual describes everything HandpanTuner does: every screen, every button, every setting, every colour and every message. You can read it without opening the app, or keep it open alongside the app while you work.

Updated in September 2026.

1Getting started

1.1What you need

• A recent browser, on a computer (Windows, Mac, Linux), on Android, iPhone or iPad. There is nothing to download and no account to create.
• A microphone. The one built into your phone or computer is good enough for measuring. A good external microphone, placed close to the note, picks up weak partials and high frequencies better.
• An internet connection the first time, to load the app and, if you have one, to activate your licence. After that, the tuner works offline (see Offline use, data and privacy).

1.2The welcome screen

This is the screen you see when the app opens. It contains:

• Unlimited access: starts the tuner if a licence is active on this device. Otherwise, this button opens the licence activation window (see Activating a licence).
• Free trial: starts the tuner in trial mode. Inside the button, under its name, you see the time you have left today (“all features · 30 min left today”) and the trial days already used (“trial: 3/14 days used”). This second line turns a lighter colour when only two days remain. Until the server has replied (or when there is no connection), it simply restates the offer: “trial: 14 days · 30 min per day”. Once the trial is used up, the button reads “free trial ended”.
• ⬇ Install the app: only appears if your device allows installation, with the text “Installs like a real app · then works offline” (see Installing the app).
• Scale builder free: opens the site's second tool (see The scale builder).
• Discover the tools ↓: scrolls down to the feature overview, followed by the sections Tuning a handpan, What HandpanTuner shows, Why a handpan goes out of tune and Frequently asked questions. The ↑ Back to top button takes you back up.
• The language selector, at the top of the screen.
• At the bottom of the page: the links Scale builder, How to tune a handpan, User manual (this manual), Buy the tuning software and Legal notice; the contact address, followed by a small ⧉ button that copies it (it shows ✓ for a moment); and links to the site in each language.

1.3Allowing microphone access

When you press Unlimited access or Free trial, the browser asks for permission to use the microphone. Allow it: without a microphone, nothing can be measured.

If microphone access is denied or the microphone is unavailable, the tuning screen opens anyway, with a red banner: “Microphone unavailable. Check your browser permissions.” Allow microphone access in the browser settings (on a computer, the icon to the left of the site address; on a phone, the site permissions), then press Retry. The ✕ closes the banner.

The app asks the system to turn off echo cancellation, noise suppression and automatic gain, which would distort the measurement. If the system keeps any of this processing active anyway, a ⚠ warning appears in the settings, next to the microphone selection (see Microphone).

1.4The free trial

The trial gives access to every feature, with no bank card or account needed. Its current terms: 30 minutes a day, over 14 days of use. The Free trial button always shows how much you have left.

• Time only counts while the tuner is on screen. If you switch to another tab or another app, the countdown stops.
• A day only counts if you actually use the trial on that day.
• The trial is tied to the internet connection: devices on the same connection (a workshop, a household) share the same trial.
• When the day's time is up, the tuner stops and the licence window appears with the message “Today's trial is over. Come back tomorrow, or unlock everything with a licence.” The number of days used is sometimes added after it.
• When all the days have been used: “Your free trial is over: it covered 14 days of use. Unlock everything with a licence.”

1.5Activating a licence

After purchase, you receive a key in the form HPTN-XXXX-XXXX-XXXX, shown on screen and sent by email. To activate it:

1. Open the Activate HandpanTuner window: press Unlimited access on the welcome screen (as long as no licence is active) or Key in the settings, on the Licence row. The window says: “Tuning mode requires a licence. Enter the key you received after purchase.”
2. Type the twelve characters into the three boxes after “HPTN” (digits and the letters A to F). The cursor moves on to the next box by itself; Backspace in an empty box takes the cursor back to the previous one. You can also paste the whole key, with or without “HPTN-”, into any box: it is split across the boxes automatically.
3. Press Activate (or Enter). The window closes and the tuner starts.

In the same window, Buy a licence opens the purchase page and Close closes the window. If activation fails, a message appears below the boxes:

• “Invalid key.”: check what you typed.
• “Cannot reach the server. Check your connection, then try again.”
• “You are offline. Activating a licence needs a connection.”
• “The server returned error…” or “Unexpected reply from the server…”: try again a little later, and write to us if the problem persists.
• The server may also give its own reason for refusing, for example when the key is already active on the maximum number of devices.

Two devices. A licence can currently be used on two devices, or more precisely in two browsers: Chrome and Firefox on the same computer take up two slots. The Licence row in the settings shows how many are in use (for example 1/2 devices). To move to another device, for example before selling a computer, press Release, then confirm (“Release this device? The licence will be deactivated here and the slot will become available for another device.”). The message “Device released. You can now activate your key on another device.” appears and the app reloads: your key is still valid and can be activated elsewhere. If the request fails, the app shows “Server unreachable. Try again online.” (or a message about the connection). A slot left unused for 90 days is also released automatically.

Offline. Once activated, the licence works for 30 days without an internet connection. It is checked again automatically whenever a connection is available: when the app opens, and when you return to it after more than an hour. After 30 days without any check, the Licence row reads “Expired, go online to renew”: reconnect the device to the internet and reopen the app.

The other states this row can show: “Not activated”, “Active · offline until …” (with a date), and, for a temporary key (separate from the free trial), “Trial, 12 days left (until …)” then “Trial ended”. If the server rejects a key that is no longer valid, the app tells you: “Your licence could not be verified by the server. Please enter your key again.”

1.6Installing the app

Once installed, the app has its own icon, opens full screen without the browser bars and works offline. This is the most comfortable way to use it.

• Computer and Android: press ⬇ Install the app on the HandpanTuner welcome screen, then confirm. If direct installation is not offered, the Install on Android window explains what to do: open Chrome's ⋮ menu at the top right, choose Install app (depending on the version: Add to Home screen), then confirm. Got it closes the window.
• iPhone and iPad: the button opens the Install on iPhone window, which explains the steps in Safari: tap Safari's Share button (at the bottom of the screen on iPhone, at the top on iPad), choose Add to Home Screen, then Add. Got it closes the window.

1.7Updates

The app updates itself. When a new version is ready, a banner announces it: “A new version is available.” Update reloads the app straight away; the ✕ closes the banner, and the new version takes effect the next time you open the app. The version number appears next to the HandpanTuner name at the top of the screen, and in the settings, on the Version row.

2The tuning screen

The tuning screen is laid out differently depending on the width of the window: two columns on a computer, a single column on a phone or on a tablet held upright. The tools are the same.

2.1On a computer

1. Toolbar: Capture, Logbook, History (see Captures and the logbook, and The history).
2. The display, which shows the three partials (see The display).
3. The spectrum and its zoom bar (see The spectrum).
4. The spectrogram, with the ratio banner and the bar that sets the frequency range (see The spectrogram).
5. The stability graph and its scale buttons (see The stability graph).
6. The reference pitch 440 432 − A4 + and the Settings button.
7. The sound generator, always open on a computer (see The sound generator).
8. Note selection (see Choosing the note to tune).

At the top right: the language selector and the button, which switches the browser to full screen.

2.2On a phone or tablet

At the top of the screen, a row of buttons:

• Capture: prepares a capture for the logbook;
• Logbook and History;
• Sound: scrolls down to the sound generator, at the very bottom;
• Settings;
• Full screen.

On a phone, the reference pitch and the language are in the settings, where the reference pitch takes up the first row.

2.3Tooltips

Labels with a dotted underline open an explanatory tooltip: hover over them with the mouse, or tap them on a touch screen. The tooltip closes by itself after five seconds, or when you tap elsewhere. Buttons also show a short description when the mouse pointer rests on them.

2.4Full screen

• The whole browser screen: use the button at the top. Press it again, or press Esc, to leave full screen.
• A single panel: each panel (display, spectrum, spectrogram, stability) has a ⤢ button (Full screen) in its top-right corner. Press it and the panel fills the whole window. Press ⤢ again to go back to showing all the panels.
• The three deviations in full screen: when a panel is in full screen, a strip along the bottom shows the three deviations (Fund., Oct., Fifth), each with its coloured value and the measured frequency in Hz. The strip's ✕ hides it (the Partials in full screen setting then switches to Off).
• Direct link: if you add ?vue=spectrogramme to the address (or ?vue=spectre, ?vue=stabilite, ?vue=afficheur), the app opens straight into that panel in full screen. Handy for a bookmark, or for a second screen dedicated to a single graph.

3Reading a measurement

3.1The three partials

Each note on a handpan produces several sounds at once. HandpanTuner continuously measures all three tuned partials at the same time:

In the spectrum, the spectrogram and the stability graph, each partial always has the same colour: gold for the fundamental, cyan for the octave, pink for the fifth.

3.2The deviation in cents

The number shown for each partial is the deviation of the measured frequency from the target frequency, in cents. A hundred cents make a semitone, so one cent is a very small difference, and the value is shown to a tenth of a cent.

• A + sign (for example +3.2): the partial is too high.
• A − sign (for example −1.4): the partial is too low.

The target frequency is calculated from the chosen note and the reference pitch (A at 440 Hz by default): the fundamental targets the frequency of the note, the octave twice that frequency, and the fifth roughly three times it (the exact value depends on the Partial reference setting). The Target offsets setting also lets you shift each of these targets.

A partial is considered in tune when its deviation stays within the tolerance: ±2 cents by default.

3.3Colours

These four colours apply to the numbers, the gauges and the rings of the wheel. In Wave and Bars, the lines in the animation box turn green when the partial is in tune (see The display). In the graphs, the colours gold, cyan and pink identify the partials, the markers you place are cream, and a frozen reference on the spectrum is verdigris.

3.4The note on screen

The name of the measured note appears in large type on the display, with its octave number in smaller type (for example D3). If the display is hidden, the note name appears on the first visible panel.

In Wheel view, the centre of the wheel shows the note, the deviation of the fundamental in large type (for example +1.8 ¢) and the target frequency (for example 146.83 Hz target). When no note is being measured, the note is replaced by a dash and the deviation by three dots.

Notes are written in letter notation, the most widely used system in the world. The number that follows is the octave number: the A used as the reference pitch is A4, and C4 is middle C on the piano.

The # sign means sharp: C# is C sharp, and A#3 is A sharp in octave 3.

4The display

The display shows the state of the three partials at a glance. It comes in four styles, which you choose in the settings on the Strobe style row (the settings refer to the display as the strobe): Wave (the default), Bars, Wheel and None.

In Wave, Bars and None, each partial has its own row: its name (FUNDA., OCTAVE, FIFTH), a ▶ button that plays the target, the deviation in cents, an animation box (empty in None) and a gauge.

4.1The gauge

• The centre line represents the target.
• The small tick marks along the bottom indicate ±5, ±10, ±25 and ±50 cents.
• The scale is not linear: it gives plenty of room to small deviations, near the centre, and squeezes the large ones together. The two ends correspond to ±100 cents.
• The green zone covers the tolerance.
• The cursor is coloured according to the deviation. It sits to the right of the centre when the partial is too high, to the left when it is too low. When the partial is in tune, the green zone and the outline of the gauge light up.

The cursor and the animations follow the measurement continuously. The number, on the other hand, refreshes at the rate chosen in the Number display setting, so that it stays readable.

4.2Wave

The box contains three wavy lines. The further the partial is from its target, the bigger the waves. They move to the right when the partial is too high and to the left when it is too low; the larger the deviation, the faster they travel. When the partial comes within the tolerance, the lines turn green; below a deviation of 0.3 cents, they are perfectly flat and still. Outside the tolerance, the lines are gold for the fundamental and blue-grey for the octave and the fifth.

4.3Bars

Bright bands scroll across the box: to the right when the partial is too high, to the left when it is too low; the larger the deviation, the faster they scroll. When the partial is in tune, they turn green and almost stop. Outside the tolerance, they are gold for the fundamental and blue-grey for the octave and the fifth.

4.4Wheel

This is the classic circular strobe, with three concentric rings:

• the outer ring, with 14 segments: the fundamental;
• the middle ring, with 18 segments: the octave;
• the inner ring, with 24 segments: the fifth.

Each ring turns clockwise when its partial is too high and anticlockwise when it is too low; the larger the deviation, the faster it turns (the speed stops increasing beyond 25 cents). It stands still when the partial is in tune. Its colour follows the usual rule: green, orange or blue, and dark grey when there is no measurement. When all three partials are in tune at the same time, a green halo lights up the wheel.

In the centre: the note, the deviation of the fundamental in large type and the target frequency. On a computer, the wheel appears next to the three rows (name, deviation and gauge). When the display is in full screen, the wheel fills the whole panel, with three chips below it, Funda., Octave ×2 and Fifth ×3: each one has a ▶ button, the deviation and the measured frequency. A faded chip indicates a weak partial, whose measurement is less reliable. The name on each chip opens a tooltip: “The note's main sound, the one you hear loudest. The large outer ring.”, “Partial vibrating at twice the frequency: one octave above. Middle ring.”, “Partial at three times the frequency: an octave plus a fifth above. Small central ring.”

4.5None

No animation: each row keeps its name, its ▶ button, its deviation and its gauge, and the box stays empty. Useful for a calm screen, when only the numbers matter to you.

4.6Listening to the target

The ▶ button of each partial plays a pure tone at the target frequency for that partial; it turns into ■, which stops the sound. The sound follows the note when the note changes, and takes the partial reference and the target offsets into account. Several partials can sound together. This is useful for comparing the instrument's note with its target by ear.

There has to be a current note: in Fixed note mode, there always is; in Auto mode, the button does nothing until a note is recognised, and the sound stops when the note is no longer detected.

5Choosing the note to tune

The note selection block is in the right-hand column on a computer, and below the graphs on a phone. From top to bottom: the scale button (and, for a named scale, the ding selection), the three modes Auto, Fixed note and Detect, the octave buttons and the note grid.

5.1Auto

The app recognises and measures the note you strike. The recognised note lights up in the grid.

• With the free scale (chromatic), it picks the semitone closest to the sound played.
• With a named scale or My scale, it only picks notes from that scale: the one closest to the sound played, provided the sound is close enough to it. Choosing your instrument's scale therefore avoids a lot of confusion.

If you tap the lit note in the grid, the app locks onto it (Fixed note mode).

5.2Fixed note

The app stays on a single note, even if another one sounds. This is the mode to use while hammering: blows struck around the tone field do not change the target.

• Fixed note locks onto the note being played or, failing that, the last note recognised in Auto mode.
• You can also tap any note in the grid: the app locks onto it directly.
• Tapping the locked note again takes you back to Auto.

If you clearly play a different note, a red banner tells you so at the top of the screen, for example “You are playing A3, locked on D3”. The measurements still refer to the locked note. The banner disappears when you play the locked note again, or after one second of silence.

5.3Detect

Press Detect, then strike the note you want to tune. The button shows “Strike a note…” while it listens. As soon as the note sounds clearly, well above the sensitivity threshold, for about 0.4 seconds, the app locks onto it and the button returns to normal. Press Detect again to cancel. If you were in Fixed note mode, the app switches back to Auto while it listens.

Tooltip: “Press, then strike the note you want to tune: the app detects it and stays locked on it until you change.”

5.4The note grid

• With the free scale, the grid shows the twelve notes from C to B, and the Oct 1 to Oct 6 buttons choose the octave of these notes.
• With a named scale, it shows the notes of the scale with their octave (for example D3, A3, A#3, C4…).
• With My scale, you use it to tick your notes (see below).

The recognised note (in Auto mode) or the locked note (in Fixed note mode) is highlighted.

5.5Scales

The scale button shows the current scale, for example Scale: free (chromatic) ▾. It opens the list of scales:

• a search field: type part of the name (Kurd, Celtic, Hijaz…); Esc closes the list, and so does a click outside it;
• Scale: free (chromatic) and ★ My scale (custom);
• then the scales, grouped into Minor, Major, Oriental & world and Other.

For a named scale, two lists appear next to the button: the ding note (C to B) and its octave (Oct 2, Oct 3 or Oct 4). The scale is built from this ding, D3 by default. Choosing a scale or changing the ding switches back to Auto mode.

5.6My scale

Choose ★ My scale (custom) to build the exact list of your instrument's notes. A hint appears: “Tick your handpan's notes in the grid (switch octaves with the buttons). Tap a chip to tune it, ✕ to remove it.”

• Choose an octave (Oct 1 to Oct 6), then tap the notes you want to add. Tap a ticked note to untick it.
• Each note you add appears as a chip above the grid; the chips are sorted from lowest to highest. Tap a chip to lock the tuner onto that note (tap it again to go back to Auto); its ✕ removes it from the scale.

Your scale is kept in the device's browser: next time you open the app, choose ★ My scale (custom) again from the list of scales to get it back. It is also written into the page address (the part starting with #g=): a bookmark or a shared link reopens the tuner directly on this scale.

6The reference pitch (A4)

The reference pitch is the frequency of A (A4), from which all the targets are derived. The international standard is 440 Hz; some handpans are tuned to 432 Hz.

• 440 and 432: the two common values, one press away.
• − and +: lower or raise it by one hertz.
• The field next to “A4” accepts any value from 400 to 480 Hz, to the nearest tenth of a hertz. Confirm with Enter or by leaving the field.

The change applies immediately to all the targets and is remembered. On a computer, the reference pitch is at the top of the right-hand column; on a phone, it is in the settings. Its tooltip: “Reference pitch for A. 440 Hz is the international standard. Some handpans are tuned to 432 Hz.”

7The spectrum

7.1What it shows

The spectrum shows where the energy of the sound lies at this very moment: frequencies from left to right (on a logarithmic scale, where each octave takes up the same width), level from bottom to top. You can see which partial dominates, and whether a stray peak appears where nothing should be sounding.

• The blue curve, filled underneath: the spectrum of the sound right now.
• The peak marks, lighter in colour: each frequency leaves a trace of the highest level it has reached, and this trace slowly falls back. This lets you see which partial dies away first. How fast the peak marks fall depends on the Scrolling setting.
• Three vertical lines in the colours of the partials mark the target frequencies: fundamental (the thickest line), octave, fifth. A peak sitting exactly on its line means that partial is in tune. These lines follow the partial reference and the target offsets.
• At the bottom right, the legend: ● Fund. ● Octave ● Fifth.
• The vertical scale adapts: when the sound is very loud, the top of the scale rises, and its value is shown at the top left (for example −22 dB).

You can place markers on the spectrum and read a precise frequency by hovering over it: see Markers and readout cursor.

7.2Zoom

The bar under the spectrum selects the frequency range shown. Your choice is remembered.

7.3Freezing a reference

The Freeze button keeps a snapshot of one strike so that you can compare it with the strikes that follow, for example before and after a hammer blow, or between two notes:

1. Press Freeze: “Capture armed: play the note whenever you're ready, it will freeze by itself.”
2. Strike the note. The app keeps the clearest spectrum from the next two seconds and draws it in verdigris behind the live spectrum: “Reference frozen: play to compare.”
3. Play again: you immediately see what has moved since the reference.

Press Freeze again to clear the reference (or to cancel an armed capture): “Comparison cleared”. The button stays lit while a capture is armed or a reference is shown.

Button tooltip: “Freeze a reference: arm it, play the note whenever you want, its strongest snapshot stays overlaid.”

7.4Clearing the markers

The ✕ at the end of the zoom bar clears all the markers at once, on both the spectrum and the spectrogram.

8The spectrogram

8.1Reading the spectrogram

The spectrum shows a single moment; the spectrogram shows how it evolves over time. You can see which frequencies last, which ones die away first, what appears on one strike and not on another, and even the secondary frequencies that handpan makers call shoulder tones.

• Time runs from bottom to top: the present moment is at the bottom, and the image moves up one line every 28 milliseconds. The spectrogram keeps roughly the last 22 seconds; how much of it you see depends on the height of the panel.
• Frequencies run from left to right, on a logarithmic scale anchored to the fundamental of the current note. By default, the range goes from 0.7 to 24 times this fundamental: each frequency is read as a ratio to the note (×2, ×3, ×9 and beyond). With no note, the range starts at 60 Hz.
• Colour shows the level: from midnight blue (weak) to turquoise, then gold and white (strong), between about −95 and −35 dB.

You can place markers on it, follow a secondary partial while you work and read a frequency by hovering: see Markers and readout cursor.

8.2The banner under the graph

Under the spectrogram, a banner helps you locate the frequencies:

• light and dark bands, like the white and black keys of a piano, mark the notes;
• a grey ruler marks the whole-number multiples of the fundamental that fall within the range, with their labels (×1, ×2, ×3, then others as space allows);
• three coloured lines show the targets of the fundamental, the octave and the fifth, at their exact position according to the partial reference and the target offsets.

8.3Choosing the frequency range

The bar under the banner represents the whole possible span, from 0.35 to 32 times the fundamental. The highlighted section is the range shown, which is also given on the right (for example ×0.7-24). Its tooltip: “Drag to move, pull the edges to zoom”.

• Drag the highlighted section to move the range without changing its width.
• Pull one of its edges to widen or narrow it.
• Click elsewhere on the bar to centre the range on that point.
• Mouse wheel over the bar: zoom in or out around the pointer.

The range cannot be narrower than a ratio of 1.6. It goes back to the default range (0.7 to 24 times) each time you open the app.

8.4Freezing the state in the background

The Freeze button, at the end of the range bar under the spectrogram, freezes the current image as a semi-transparent background: new lines are drawn over it, and you can see what has shifted. The message “State frozen behind” appears. Press the button again to clear it (message “Background cleared”). Button tooltip: “Freezes the current state behind, to see the shift”.

9Markers and readout cursor

A marker pins down a precise frequency on the spectrum and on the spectrogram. Use it to find a partial again, to follow it while you work on the note and to listen to it in the generator. Markers are also saved with your captures.

9.1Placing, moving, deleting

• Place: click on the spectrum or the spectrogram (on a touch screen, tap it). A cream vertical line appears, with a small triangle at the top and its frequency (for example 1043.2 Hz). The same marker is visible on both graphs.
• Move: drag the line. It brightens while you move it.
• Delete: tap the small ✕ at the foot of the line, or the one in the marker's box in the list (see below). The ✕ at the end of the spectrum's zoom bar clears all the markers.

The maximum number of markers depends on the size of the spectrogram (from 3 to 40). Beyond that, each new marker replaces the oldest one. Until you have placed your first marker, a hint appears in the corner of the spectrogram: “Click to place a marker”.

9.2The marker list and tracking

At the top left of the spectrogram, each marker has its own box:

• on the left, its position relative to the fundamental of the current note (for example ×2.97), or its frequency in Hz when no note is being measured;
• on the right, a deviation in cents showing how far the peak under the marker has moved since you placed it;
• a ✕ to delete the marker.

When you place a marker, the app measures where that peak was, on average, over the seconds recorded in the spectrogram: this is its starting position. From then on, it continuously compares the current position of the peak with that starting position.

Once there are at least two markers, a final box, Clear all, deletes them all.

9.3The readout cursor

Hover over the spectrum or the spectrogram with the mouse: a dotted line follows the pointer, with a label giving the frequency (in Hz), the level at that point (in dB) and, on the spectrogram, the age of that line (for example −3.2 s).

On a touch screen, hold your finger down for a third of a second: the label appears, and disappears 1.6 seconds after you lift your finger. Like any touch on the graph, this press also places a marker; remove it with its ✕ if you do not need it.

10The stability graph

The Stability panel plots the deviation of each partial over the last few seconds. A number on its own cannot show whether a note drifts while it rings, or whether it wavers between two very close pitches: this graph can.

• Three curves: fundamental, octave, fifth (legend at the bottom right). The most recent moment is on the right.
• Time span shown: 1.2 seconds, 1.8 seconds or 3 seconds, depending on the Scrolling setting (Fast, Normal, Wide).
• Vertical axis: the deviation in cents. The centre line is the target; the green band covers the tolerance; dotted lines, numbered on the left, act as gridlines (for example +13, +5, −5 and −13 on the ±25 scale).
• Scale: the ±10 ¢ ±25 ¢ ±50 ¢ ±100 ¢ buttons under the graph (±25 by default, remembered). The current scale is shown at the bottom left. A value beyond the scale stays pinned to the edge.
• A curve breaks off when its partial is no longer measured.
• A curve fades and thins as the sound dies away, and regains its full brightness on the next strike. This lets you tell the full body of the sound from its more fragile tail. The effect is purely visual: the measurement is unchanged.

How to read it: a flat curve means a stable note. A curve that rises or falls means a note that moves while it rings. A curve that undulates regularly indicates two very close pitches beating against each other. The very first moments after the strike are often unsettled: read the sustained part of the sound instead.

11Captures and the logbook

11.1Taking a capture

The Capture button (“Saves the spectrogram and the measurements to the logbook.”) records the state of the current note: the spectrogram image with its banner, the note name and its target frequency, the three deviations and the measured frequencies, the reference pitch, the spectrogram range and your markers. A note must have been measured; otherwise: “No note detected: strike a note before capturing.”

The Save this capture window then opens:

• a preview of the image;
• Instrument: the name of the instrument, already filled in with the one from the previous capture;
• Notes: your own comments (what you did, what is left to do…);
• Export: downloads the image straight away, with its details written on it, without saving it to the logbook;
• Cancel (or a click outside the window): discards the capture;
• Save: stores the capture in the logbook.

If the browser's storage is full, the window says so: “This capture could not be saved: browser storage is full. Export this image, then free some space in the logbook.”

11.2The logbook

The Logbook button opens the Tuning logbook: the Saved captures list, newest first, with the total count. Each capture shows its image (with your markers drawn on it), the name of the instrument and the note, the date and time, and a summary of the measurements. Its buttons:

• ✕ Delete, after confirmation: “Delete this capture? … This cannot be undone.”
• → 3 (the number of markers in the capture, if it has any): Send the markers to the graph. They are put back on the spectrogram, the logbook closes, and a message confirms: “3 markers placed on the spectrogram”. Handy for finding, weeks later, the frequencies you were keeping an eye on.
• ⛶ View larger (details in 11.4).
• ✎ Rename: the app asks for the Instrument name, then for your comments (Notes).
• Clicking a capture selects or deselects it.

Below the list: Select all, Deselect, Export and Delete (which act on the selection; deleting asks for confirmation: “Delete 4 capture(s)? This cannot be undone.”), and Import. The number of selected captures is shown alongside (for example “3 selected”). Close the logbook with its ✕ or by clicking outside it. While it is empty, it says: “No captures yet. Press Capture after playing a note.”

11.3Exporting and importing

Select the captures, then press Export: a window shows how many are selected and offers three formats. If nothing is selected, the app warns you: “Select the captures to export first.”

Cancel, or a click outside, closes the window without exporting anything.

Import: choose a .json file you exported earlier. Its captures are added to the logbook; any that are already there are not duplicated. A message confirms the import (“12 capture(s) imported.”) or reports a file that is not a logbook (“Unreadable file.”).

11.4View larger

The ⛶ button on a logbook capture, or on a capture in the history, opens it in a large view:

• Zoom: mouse wheel or two-finger pinch. A double-click zooms in on the spot you point at; another double-click returns to the whole image.
• Move around: drag the image.
• Add a marker: click on the image. The app places it precisely on the nearest peak (unless there is already a marker very close by).
• Remove a marker: double-click it, or tap its ✕ in the list.

At the top, you see the measurements of the capture and the list of its markers (ratio to the fundamental and frequency), with Send 3 markers to the graph and Clear all. Export as image downloads the image with its details. One line sums up the instrument, the note, the target frequency of the fundamental, the date, the reference pitch and the zoom level. Markers added or removed here are saved in the capture. Close it with ✕ or by clicking outside.

11.5Storage space

Captures are stored in the device's browser, and nowhere else. A gauge under the list shows how many there are and how much space they use (for example “18 captures, 1.4 MB used.”). The logbook and the history share about 5 MB of space.

• At 60%: “Space is filling up. Consider exporting.”
• At 85%: “Almost full, export, then delete the oldest.”

If writing to the logbook fails for lack of space (saving, renaming, importing…), a message tells you: “Storage full: export your captures, then delete the oldest.”

The logbook shows two reminders: “These captures are kept in this browser. Export them regularly: clearing the cache erases them.” and “The image carries the details but cannot be imported back. Use the logbook export for that.”

12The history

While you work, the app automatically keeps captures of the spectrogram and the measurements, so that you can go back to a moment you forgot to capture.

• At most one capture roughly every 22 seconds, and only if you have played in the meantime.
• The 20 most recent are kept (up to about 2 MB); beyond that, the oldest one is deleted.

The History button opens the Spectrogram and measurement history panel, with the text “Automatic captures while you work, image and measurements. The oldest is dropped once full.” The list runs from newest to oldest. Close the panel with its ✕.

Each capture shows its image, the note, the time, the number of markers (for example 2 ✛) and the measurements. Its buttons:

• ⛶ View larger (details in 11.4);
• ↑ Add to the logbook: the capture is saved to the logbook (“Added to the logbook.”, or “Storage full…” if there is no space left);
• ✕ Delete.

At the bottom: Turn off stops the automatic captures (the button becomes Turn on; this choice is remembered), Clear empties the history after confirmation (“Clear the whole history?”), and a counter shows how full it is (for example 12 / 20). When the list is empty, it shows “Nothing yet. The history fills up on its own while you play.”, or “History turned off.” if automatic captures are turned off.

Opening the logbook or the history stops the generator's sound.

13The sound generator

The generator plays any frequency: a frequency of your choice, a note from the keyboard, a multiple of the current note, a tuning target or a marker. On a computer, it is always open in the right-hand column. On a phone, it is at the very bottom of the page, and the Sound button takes you straight there.

13.1Free frequency

The ▶ button plays the frequency entered in the field and turns into ■ to stop it. The field accepts 20 to 8000 Hz, to the nearest tenth of a hertz. Next to it, you see the nearest note, with its deviation when the frequency falls between two notes, and the frequency being played (for example D3 · 146.8 Hz or D3 +37 ¢ · 150.0 Hz). You can change the value while the sound is playing.

13.2Note

A twelve-key keyboard from C to B, with octave selection (− and +, from 0 to 8; 3 to begin with). Press a key to hear the note, calculated from the current reference pitch.

13.3Multiple of the current note

The ×1 to ×24 buttons play the whole-number multiples of the fundamental of the current note (up to 16,000 Hz). This is the series of pure harmonics, independent of the settings: use it to explore the spectrum and to identify a frequency seen on the spectrogram. When you hover over a button, it shows its frequency and the name of the nearest note.

13.4Partials of the note

Three buttons, Fund., Oct. and Fifth, with their frequencies: these are the tuning targets of the current note. Unlike the multiples, they follow the Partial reference setting (shown next to the heading: Tempered, Just or Custom) and the Target offsets.

13.5My markers

One button for each marker you have placed, with its frequency and its ratio to the fundamental. If there are no markers: “Place a marker on the spectrogram: it will appear here, ready to hear.”

13.6Timbre and level

• Timbre: ∿ pure tone (sine wave, the default); △ triangle, slightly richer; ◺ sawtooth, very rich in harmonics. Changing the timbre restarts the sound that is playing.
• Level: the slider sets the volume, from 0 to 100 (45 to begin with).

13.7How it behaves

• The button for the sound that is playing is highlighted. Tapping the button of the frequency that is playing stops it.
• Until a note is detected, the Multiple of the current note and Partials of the note sections say: “Play a note or place a marker to get shortcuts.”
• When the note changes (in Auto mode or through a new lock), a multiple or a partial that is playing follows the new note. A frequency typed in by hand, however, never changes.
• Opening the logbook or the history stops the sound.
• The generator's settings (timbre, level, octave) are not remembered from one session to the next.

14Settings

The Settings button (on a phone, the icon) opens the settings panel: at the bottom right on a computer, at the bottom of the screen on a phone. Close it with its ✕. Every change applies immediately, and most settings are remembered (see What the app remembers). Here are the settings in the order in which they appear. The indented texts are the tooltips.

15What the app remembers

Everything the app remembers is kept in the browser: each device, and even each browser, has its own settings.

16Offline use, data and privacy

16.1Without a connection

Once loaded (and preferably installed), the app works offline: measurement, graphs, logbook, history, generator and settings. A connection is still needed for the first load, to activate a licence, to check it again at least once every 30 days, to receive updates and to open the scale builder.

16.2Your data

• Sound is analysed live, on your device. It is neither recorded nor sent anywhere. Captures are images of the spectrogram, not sound recordings.
• The logbook, the history and the settings stay in the device's browser. They are not sent anywhere and are not synchronised between your devices. Clearing the browser data (or “clearing the cache” for the site) deletes them: export your logbook regularly.
• What goes through our servers: licence verification (the key and a technical identifier for the device), trial time tracking (tied to a one-way hash of your IP address, which itself is never stored) and anonymous traffic statistics, such as the number of visits and trials, with no personal data at all. Full details are in the legal notice.

17Measuring tips

• Set the reference pitch (440 or 432 Hz) before you start.
• Place the microphone close to the note you are measuring, and keep the same position from one measurement to the next.
• Work somewhere quiet. A fridge, a ventilation system or a noisy computer adds peaks to the spectrum.
• Strike as you would when playing, let the note ring, and read the sustained part of the sound rather than the moment of the strike.
• Lock the note (Fixed note or Detect) while hammering: the target will no longer jump.
• If the readings jump on impact, set the attack filter to 80 or 160 ms.
• If a weak partial disappears, raise the sensitivity; if room noise causes spurious readings, lower it.
• Compare before and after a hammer blow with Freeze on the spectrum, or Freeze on the spectrogram.
• Capture each note at the start and end of a session: the logbook keeps a record of the instrument over time.

18Troubleshooting

19Glossary

20The scale builder

A second tool, free and with no licence required: build a scale note by note, listen to it, see it laid out on both shells, compare several scales and export them as images. You can open it from the welcome screen, the site footer or the settings (Scale builder row, Open button).

Open the scale builder

21Contact

A question, a problem, an idea? Write to contact@handpantuner.app and, if possible, mention your device, your browser and the version number (Version row in the settings).

See also: How to tune a handpan · Buy the tuning software · Legal notice.