1Getting started

A cartwall is a grid of large pads, and each pad holds one audio clip. Press a pad and its clip plays at once. Radio stations use them for jingles and sound effects; in a school they are just as useful for backing tracks, stings, walk-on music and sound cues.

1.1What Harrison Cartwall does

Plays clips instantly from pads, with the mouse, a touch screen or the keyboard.
Gives you three banks (A, B and C) of up to 36 pads each, so one screen can hold a whole show.
Edits without leaving the page. Trim the start and end of a clip (with zoom for precision), add fades, change the level, speed or colour, and set how each pad behaves.
Protects your show. Meters, a safety limiter, an ending warning, a one-touch STOP ALL, and a Show Lock that hides everything that could be changed by accident.
Saves itself. Your pads and audio are kept in the browser automatically, and you can export a backup file at any time.

1.2What you need

A computer with a current web browser. Chrome and Edge are recommended because they also let you choose which audio output to use (see Settings, chapter 7).
Speakers, headphones or an audio interface.
An internet connection when you open the page. The page downloads its fonts and icons each time it loads; your audio is not uploaded anywhere.
Your audio clips, as ordinary files (WAV, MP3, M4A/AAC, OGG, FLAC and similar; the exact list depends on your browser).

Your audio stays on this computer. Clips you load are stored inside this browser on this computer. They are never sent to a server. That also means a different computer, browser or user profile starts with an empty cartwall. Chapter 8 explains how to back up and move your work.

1.3Quick start

The fastest way to see how it works is the Demos button, which loads six built-in sample sounds. Try it first, then follow the steps with your own audio.

Open the page and wake the audio. Browsers keep sound switched off until you interact with the page. If an amber bar says the audio engine is on standby, click anywhere (or Activate Audio), or just press a key.
Load a clip. Click an empty pad and choose an audio file, or drag one or more audio files from your computer onto the pad grid.
Play it. Click the pad, or press the key shown in square brackets on the pad, such as Q. The pad lights up and counts down.
Stop it. Press the pad again, or press Space to stop everything. The red STOP ALL button does the same.
Adjust it. Click the cog ⚙ on a pad to rename it, trim the start and end, set fades or choose a colour.
Back it up. Click Export and keep the file somewhere safe (chapter 8).

2The main screen

Everything you need during a show is on one screen. The numbers in the picture match the list below it.

The main screen with numbered callouts — Figure 1. The main screen with two pads playing: Radio Jingle Chord and Radio Loop Rhythm Bed. On a narrower window the header wraps onto two lines, as shown here.

1	Studio clock. The computer's time (24-hour) and date, large enough to read across a studio.
2	Bank buttons A, B, C. Switch between three separate walls of pads (also `F1` `F2` `F3`). A small green dot on a bank button means a pad in that bank is playing while you are looking at another.
3	Grid. Choose how the pads are laid out: 3×3, 3×4 (the default, 12 pads) or 4×4, as rows × columns.
4	+ Pad / − Pad. Add a pad to the end of the current bank (up to 36), or remove the last one.
5	Export / Import. Save the whole cartwall to a backup file, or load one back.
6	Demos / Reset All. Load the six sample sounds, or clear every pad on every bank.
7	Lock, Settings and Fullscreen. Show Lock hides the editing controls; Settings opens the options; Fullscreen fills the screen.
8	Level meters. Left and right output level. The CLIP light turns red if the output reaches full scale, and stays lit until you click it.
9	Master mute and volume. One control for the whole output. It is set to 90% to begin with.
10	STOP ALL. Stops every playing pad on every bank.
11	Pads. One clip each. Press to play.
12	Empty pad. Click it to choose a file, or drop a file on it.
13	Playing count. How many pads are playing across all banks.
14	Save status. Shows Saved with the time of the last automatic save (see chapter 8).
15	Guide & Hotkeys. Opens a short built-in guide.

2.1Anatomy of a pad

A single pad with numbered callouts — Figure 2. A pad that is playing on a loop.

1	Hotkey. The keyboard key that plays this pad. A dash means no key is assigned.
2	Mode badges. Small labels showing how the pad behaves: SOLO, LOOP, HOLD, RETRIG and G1–G4 (mute group). Chapter 4 explains each.
3	Drag handle. Drag it onto another pad in the same bank to swap their places.
4	Cog. Opens the pad editor (chapter 6).
5	Bin. Clears the audio from the pad but keeps the pad itself.
6	Cross. Removes the pad from the bank altogether.
7	Title. The name you gave the pad. It starts as the file name.
8	File name. The audio file the pad was loaded from. Empty pads say EMPTY.
9	Time. When idle, the length that will play (after trimming and speed). While playing, the time remaining with a minus sign; looping pads show ∞ and the time left in the current pass.
10	Status light. Green: audio loaded. Pulsing cyan: playing. Grey: empty.
11	Progress bar. The lighter area fills from left to right as the clip plays. The faint picture behind the text is the clip's waveform.

Reading a pad at a glance. A bright outline and glow means the pad is playing. A pad that flashes red is in its final seconds (the ending warning, chapter 7). The pad colour is chosen by you; many people use one colour per type of sound, for example red for jingles and green for background beds.

3Loading and managing audio

3.1Putting a clip on a pad

There are three ways to load audio:

Click an empty pad and choose a file from the window that opens.
Drag a file onto any pad from your computer. If the pad already has a clip, it is replaced.
Use Load Audio in the pad editor to replace the clip on an existing pad (chapter 6). Your other edits in the editor are kept, but the trim points go back to the full length.

The pad takes the file's name as its title and shows its length straight away. Supported files include WAV, MP3, M4A/AAC, OGG, FLAC and AIFF, depending on the browser. Mono and stereo files both work. If a file cannot be read, a red message says Could not decode and the pad is left as it was; converting the file to WAV or MP3 normally fixes it.

3.2Loading many files at once

Select several audio files and drag them onto the grid together. The first goes on the pad you dropped them on; each of the others goes on the next empty pad after it, skipping any pad that already has audio. If the bank runs out of pads, new ones are added automatically up to the limit of 36 per bank; anything that does not fit is skipped, and a message tells you so.

Tip. To set up a rehearsal in a couple of minutes, name your files in the order you want them (01 Intro.mp3, 02 Verse.mp3 …), drop them all on the first pad, and the pads fill in sequence.

3.3Clearing, removing and undoing

Action	What happens
Bin on a pad	Removes the clip and resets the pad's settings (trim, fades, level, speed, mode and mute group). The pad stays in place, keeps its hotkey and colour, and is renamed to its default.
Cross on a pad	Deletes the pad. The pads after it move up one place. At least one pad must remain in each bank.
− Pad	Removes the last pad of the current bank, even if it holds a clip.
Reset All	Clears every pad on all three banks after you confirm. This cannot be undone, so export first if there is any doubt.

Undo. After the bin, the cross or − Pad, a message appears at the top right with an Undo button. It stays for about seven seconds. Use it straight away if you tapped the wrong thing.

3.4Size and length of clips

Clips are decoded into the computer's memory so that they start instantly. Stereo audio takes roughly 20 to 25 MB per minute of playing time. A few dozen jingles and tracks is no problem, but loading very long recordings (for example a whole concert) onto many pads may slow down a computer with little memory. If you only need part of a long file, trim it in the editor so that only that part plays.

3.5The Demos button

Demos loads six synthetic sounds onto the first six pads of the current bank: a sweeper, a jingle chord, a bass drop, a 1 kHz bleep, a chime and a looping bed. They exist so you can try everything in this manual without any files. If those pads already hold audio, you are asked to confirm before they are replaced.

4Playing and controlling sound

4.1Starting a pad

Click or tap a pad, or press its hotkey. Pads start the instant you press, not when you let go, so the response is as quick as the computer can make it. Hotkeys work only for the bank on screen; a key pressed with Ctrl, Alt or ⌘ is ignored so that normal browser shortcuts keep working.

Each bank starts with these keys for its first 24 pads, from left to right and top to bottom:

Pads 1–4	`1` `2` `3` `4`	Pads 5–8	`Q` `W` `E` `R`
Pads 9–12	`A` `S` `D` `F`	Pads 13–16	`Z` `X` `C` `V`
Pads 17–20	`5` `6` `7` `8`	Pads 21–24	`T` `Y` `U` `I`

Pads beyond the 24th start with no key. You can give any pad any key in the editor (section 6.4).

4.2Trigger modes

Each pad has a trigger mode, chosen in the editor. It decides what a press does.

Mode	Behaviour	Good for
Toggle (no badge)	Press once to start; press again to stop. This is the default.	Backing tracks, beds
Retrigger RETRIG	Every press starts the clip again from its in-point, cutting off the earlier play with a very short fade. A press never stops it.	Stings, sound effects, claps
Hold HOLD	Plays only while the pad (or its key) is held down, and stops when you release it.	Applause, risers, anything you want to cut yourself

4.3Solo, mute groups and looping

Solo Mode (SOLO). Starting this pad stops every other pad on every bank. Use it for a track that should always play on its own.
Mute group (G1 to G4). Pads with the same group number cut each other off: starting one stops any other pad in the same group, on any bank. Put your backing tracks in one group and the next song replaces the last without anyone pressing stop. Pads with None are unaffected.
Loop Play (LOOP). The clip repeats between its in-point and out-point until you stop it. Looping pads show ∞ in their time display.

4.4Fades

Each pad can have a fade in and a fade out, from 0 to 10 seconds. The fade in happens every time the pad starts. The fade out is used when the clip reaches its end, and also when you stop the pad yourself by pressing it again or releasing a Hold pad, so a stopped track fades away rather than cutting off. Pads with no fade out still stop with a very short fade (about 30 milliseconds) so there is no click.

4.5Stopping everything

STOP ALL, the Space bar and Esc all stop every playing pad on all banks. They ignore the pads' fade-out settings and use a fixed 50-millisecond fade, so they are quick but never click. If a window such as the editor is open, Esc closes it first; press it again to stop the sound.

Full screen. Browsers normally use Esc to leave full screen. While you are in full screen, rely on Space or the STOP ALL button. The Space bar behaviour can be switched off in Settings if it gets in your way.

4.6Meters, clipping and the limiter

The two bars at the top right show the peak level of the left and right output in decibels. Green is comfortable, amber means loud (above about −18 dBFS), and red (above about −9 dBFS) means you are close to the maximum. The thin marker above each bar holds the highest recent peak for a moment.

If the output ever reaches full scale, the CLIP light turns red and stays red until you click it, so you can tell afterwards that it happened. To avoid it, lower the pad's Gain in the editor, lower the master volume, or lower the level of the source file.

A master limiter (on by default, in Settings) sits at the end of the chain and quickly reduces any peak above about −1 dBFS. It is a safety net against sudden loud peaks, not a substitute for sensible levels.

4.7Master volume and mute

The speaker button mutes the whole output without affecting the pads; the slider sets the master level. The volume is remembered between sessions, but mute is not: the cartwall always starts un-muted.

4.8Speed and pitch

Each pad has a Speed/Pitch value from 0.5 to 2.0. It plays the clip faster or slower, like a record deck, so pitch rises and falls with speed. A value of 1 is normal. Time displays take the speed into account.

5Banks, layout and arranging pads

5.1Banks

A bank is a complete wall of pads. There are three, labelled A, B and C. Each starts with 12 pads and can hold up to 36. Switch bank with the buttons at the top, or with F1, F2 and F3. Pads keep playing when you change bank, and a green dot on the other banks' buttons tells you where the sound is coming from.

Bank B selected with a green dot on bank A — Figure 3. Bank B is showing; the green dot on A says a pad in bank A is still playing.

Ideas for using banks. One bank per song or scene; or A for jingles and stings, B for sound effects, C for backing tracks. The same hotkeys are used in every bank, so the keyboard layout stays familiar.

5.2Grid layout

The Grid buttons choose how many rows and columns the wall has: 3×3 (9 slots), 3×4 (12) or 4×4 (16). If a bank holds more pads than the grid has slots, extra rows are added automatically and every pad gets smaller so that they all stay on the screen; there is no scrolling. The grid choice applies to all banks.

5.3Adding and removing pads

+ Pad adds an empty pad to the end of the current bank (to a maximum of 36). − Pad removes the last pad. To remove a particular pad, use the cross on that pad. A new pad among the first 24 gets the default hotkey for its position; later ones start with no key.

5.4Rearranging

Drag the small grip handle (3 in Figure 2) from one pad and drop it on another in the same bank; the two swap places. Hotkeys belong to the position, not the clip, so after a swap the keys stay where they were and the clips move. This keeps the keyboard pattern the same however you arrange the wall.

6The pad editor

Click the cog on a pad to open the editor. It shows the clip's waveform and every setting for that pad. Nothing changes until you press Save Changes; Cancel (or the cross at the top right, or Esc) throws away everything you did in the window.

The pad editor with numbered callouts — Figure 4. The pad editor.

1	Waveform. The shape of the clip. The bright part plays; the grey parts are trimmed away. The green line is the in-point and the red line the out-point. Click or drag on the waveform to move the nearer line.
2	Length and peak. The full length of the clip, and the loudest point between your in- and out-points in dBFS.
3	In-Point. Where playback starts, in seconds. Type a time, drag the slider, or use the waveform.
4	Out-Point. Where playback ends (or where a looping clip goes back to the start).
5	Audition / Stop. Plays the trimmed clip once, through the master output, with a white playhead moving on the waveform.
6	Zoom controls. Zoom out, zoom level, zoom in and Reset Zoom (section 6.3).
7	Reset Trim. Puts the in-point back at the start and the out-point at the end.
8	Cart title / label. The name shown on the pad.
9	Trigger hotkey. The key that plays the pad (section 6.4).
10	Colour theme tag. Choose the pad's colour by clicking a swatch; the chosen one is outlined. Hover over a swatch to see the suggested use for it, such as Jingle or Bed.
11	Solo Mode and Loop Play. Tick to switch on (section 4.3).
12	Trigger mode. Toggle, Retrigger or Hold (section 4.2).
13	Mute group. None, or Group 1 to 4 (section 4.3).
14	Fade In and Fade Out. In seconds, 0 to 10 (section 4.4).
15	Speed/Pitch. 0.5 to 2.0 (section 4.8).
16	Gain. The pad's own level, from −30 dB to +12 dB, with a Normalise button (section 6.5).
17	Load Audio. Replace the clip on this pad with another file.
18	Delete Pad. Removes the pad from the bank (you can undo it for a few seconds).
19	Cancel / Save Changes. Discard or keep your edits.

If the pad is playing. Changes you save take effect the next time the pad is started. A clip that is already playing finishes as it was.

6.1Setting the in-point and out-point

Trimming removes silence or unwanted material from the start and end of a clip without changing your file.

Click or drag on the waveform near where you want the clip to start. The nearer of the two lines (green or red) moves to where you clicked.
Do the same near the end to set the out-point.
Press Audition to hear the result. If it is not right, move the lines again; the numbers update as you go.
For precise edits, zoom in (section 6.3) and adjust the lines there, or type exact times into the In-Point and Out-Point boxes.
Press Save Changes.

The in-point can never pass the out-point (there is always at least 10 milliseconds between them). The time boxes show thousandths of a second, so you can see the precision you get from zooming.

6.2Auditioning

Audition plays from the in-point to the out-point once, using the speed and gain currently shown in the editor, so you hear what the pad will do (fades and looping are not applied). Stop ends it. Closing the editor also stops it.

6.3Zooming the waveform

At normal size, each pixel of the waveform can represent a fraction of a second, which is fine for rough trims but too coarse for finding a breath, a drum hit or the exact start of a note. Zooming lets you magnify any part of the clip and place the in- and out-points much more accurately.

The waveform zoomed in 8 times with a time ruler — Figure 5. Zoomed in 8×. A time ruler appears, a scroll slider sits under the waveform, and the out-point (red) is placed at 1.600 seconds.

Control	What it does
Zoom in (magnifier +)	Doubles the magnification. It zooms around the trim point you moved last, if it is on screen, otherwise around the middle of the view. So: set a rough point, press zoom in a few times, and the point stays where your eye is.
Zoom out (magnifier −)	Halves the magnification. Greyed out at normal size.
Zoom level	Shows the current magnification, for example 1.0× (the whole clip), 8.0× or 64×. Hover over it to see which seconds are on screen.
Reset Zoom	Back to the whole clip.
Mouse wheel over the waveform	Roll up to zoom in and down to zoom out, centred on the mouse pointer.
Scroll slider	Appears under the waveform when zoomed. Drag it to move along the clip. `Shift` with the mouse wheel does the same.
Time ruler	Appears while zoomed, with time marks along the bottom of the waveform in seconds. The marks get finer as you zoom in.

The closest you can zoom is a window of 20 milliseconds across the whole waveform, about the length of a single musical cycle. If you type an in- or out-point that is off screen, the view jumps to show it. The zoom resets to normal each time you open the editor.

A good routine. Set both points roughly at normal size. Zoom in on the in-point, adjust it, then use the scroll slider or mouse wheel to travel to the out-point and adjust that. Zoom out and audition to check the whole clip.

6.4Choosing a hotkey

Press Rebind. The button changes to Press key…
Press the key you want. It appears in the box in capital letters.
Press Save Changes.

The cross beside Rebind removes the key so that the pad can only be clicked. Press Esc while the button says Press key… to cancel without changing anything. Space (STOP ALL) and F1 to F3 (banks) are reserved and cannot be used. If another pad in the same bank already uses the key, a yellow warning appears; if you save anyway, the key moves to this pad and the other pad is left without one, with a message to tell you.

6.5Gain and Normalise

The Gain slider changes how loud this pad is relative to the others, in decibels. It is the right tool for evening out clips that were recorded at different levels.

Normalise sets the gain automatically so that the loudest peak between the in- and out-points reaches −1 dBFS, just under full scale. It works on the part you have selected, so trim first, then normalise. The result is limited to the slider's range (up to +12 dB), and a silent selection is reported rather than changed. You can still adjust the slider afterwards.

Normalise makes a clip as loud as it can be, not as loud as the others. Clips from different sources can sound very different in loudness even when their peaks match. After normalising, listen to the pads next to each other and lower any that feel too strong.

6.6Saving or cancelling

Save Changes applies everything at once and saves the cartwall. Cancel leaves the pad exactly as it was. Delete Pad removes the pad entirely and closes the editor; use the Undo button that appears if it was a mistake.

7Settings, Show Lock and full screen

7.1Settings

Click the sliders button at the top right of the header to open Settings. They are remembered in this browser.

The Settings window — Figure 6. Settings.

Setting	What it does
Audio Output Device	Chooses which speakers or interface the cartwall plays through, separately from the rest of the computer. Useful when the cartwall should go to the PA while other sounds stay on the laptop speakers. This works in browsers that support it (Chrome and Edge). In others the list shows only System default and the sound follows the computer's normal output.
Master limiter	On by default. Quickly reduces peaks above about −1 dBFS to guard against distortion. See section 4.6.
Space bar = STOP ALL	On by default. Untick it if you would rather the Space bar did nothing. `Esc` and the STOP ALL button still work.
Ending warning	The number of seconds before the end of a clip that its pad starts flashing red, so presenters know a track is about to finish. The default is 5; set it to 0 to switch the warning off. Looping pads never flash.

7.2Show Lock

Show Lock is for the moments that matter. When it is on, everything that can change or damage the cartwall is hidden or disabled, so a stray click or a curious student cannot rearrange, overwrite or delete your pads during a performance.

The cartwall with Show Lock switched on — Figure 7. Show Lock on. The Grid, + Pad / − Pad, Export / Import, Demos / Reset All buttons and every pad's drag, cog, bin and cross buttons are hidden.

Still works while locked	Disabled while locked
Playing pads (click or hotkey) STOP ALL, `Space` and `Esc` Bank buttons and `F1` to `F3` Master volume and mute Settings and Fullscreen	Opening the pad editor Loading, dragging or swapping audio and pads Adding, removing, clearing and resetting Changing the grid Export, Import and Demos

Press the Lock button to turn the lock on (it then says Locked with a padlock), and press it again to unlock. If the editor is open when you lock, it closes. The lock is not remembered: after the page is reloaded, the cartwall always starts unlocked.

7.3Full screen

Fullscreen hides the browser's own toolbars so the cartwall fills the screen; press it again (it then says Exit Full) to return. Questions such as Export file name and Replace everything? appear inside the cartwall itself, so full screen is never interrupted. The one browser message you may still meet is the Leave site? warning described in chapter 10.

8Saving, backups and moving your work

8.1Automatic saving

Every change is saved automatically a moment after you make it: new audio, trims, titles, colours, hotkeys, bank and grid choices. The footer shows Saving… and then Saved with the time. When you open the page again, the cartwall comes back exactly as you left it, with its audio, and a message says Restored last cart configuration.

Important: where the saved copy lives. The automatic save is stored inside the browser, and is tied to this browser, this user profile and this web address. A different browser, a different Windows or Chromebook account, a different web address, or a private/incognito window will show an empty cartwall. Clearing the browser's history or "site data" deletes it. On school computers that wipe user profiles when you log off, the automatic save will not survive. Always keep an exported backup.

If the footer ever shows SAVE FAILED in red, the browser could not store your work (for example because the disk is full, or storage is switched off). Export a backup immediately and then look at the cause.

8.2Exporting a backup

Click Export. A window asks for a file name, already filled in with today's date.
Change the name if you like and press Export (or Enter).
Your browser downloads a file ending in .harrison, normally into the Downloads folder, or wherever your browser is set to save.

The backup contains everything: all three banks, every clip, trims, fades, colours, hotkeys, modes, and the grid layout. Copy it to a USB drive, a shared drive or cloud storage. Settings (output device, limiter and so on) and the master volume are stored separately and are not part of the file.

Your audio is not locked in. A .harrison file is a standard ZIP archive. If you ever need your original audio files back, make a copy, rename it to end in .zip, and open it with your normal archive tool. The clips are in the audio folder, exactly as you loaded them.

8.3Importing a backup

Click Import and choose a .harrison file.
A window warns that importing replaces everything currently on the cartwall. Choose Replace Everything to continue, or Cancel.
The cartwall loads the pads, audio and layout from the file. A message confirms, or tells you how many clips could not be read.

Backups made by earlier versions of the cartwall can still be imported. To move your work to another computer, export on the first, copy the file across, open the cartwall on the second, and import.

8.4Starting again

Reset All clears every pad on all three banks, returns to bank A and the 3×4 grid, and saves the empty cartwall. It asks you to confirm first and cannot be undone, but your Settings and master volume stay as they were. Export before you reset if there is any chance you will want the pads back.

9Running a session

The cartwall is simple to use, but live work rewards a little preparation. This chapter is a suggested routine for lessons, rehearsals and shows.

9.1Before the session

Open the page and import your show file if the computer has been used since, or check that the pads you expect are there.
Check the sound path. Press a pad and confirm it comes out of the right speakers. If not, choose the output in Settings (or in the computer's sound settings).
Set levels once. Play the loudest clips and adjust the master volume and the PA so the meters stay in the green and amber, not red. Lower individual pad Gain rather than raising the master.
Check every track you will need by clicking Audition or playing the pads, particularly in-points and out-points.
Export a fresh backup and put a copy somewhere other than this computer.
Press Lock if other people will be near the computer, and switch to Fullscreen if you like.

9.2During the session

Keep the pads you need within one bank where possible, so you never need to switch bank under pressure.
Watch the ending warning. A pad flashing red means its clip is about to finish.
Use mute groups for tracks that should replace each other and Hold mode for effects you want to cut yourself.
If something goes wrong, Space (or the STOP ALL button) clears the sound immediately.
Don't press F5, close the tab or navigate away. If audio is playing the browser will ask you to confirm.

9.3After the session

Unlock, and if you changed anything, export a new backup with a clear name such as Summer-Show-2026-07-02.
On a shared computer, remember that a log-off may erase the browser's saved copy (section 8.1), so keep your .harrison file.

9.4Ideas for school use

Rehearsal bank. Load each backing track on its own pad, trim off lead-in silence, set a short fade out, and put them all in mute group 1 so you can jump between pieces.
Assemblies and shows. Walk-on music on one bank, sound effects on another. Use Show Lock and a student operator who only needs to press pads.
Radio and podcast clubs. Jingles on retrigger pads, beds on looping toggle pads in a mute group, bumpers with a brief fade in and out.
Practice tracks. Use the Speed value (0.5 to 2.0) to slow a track down for learning a part. Remember that pitch changes with speed.

Use audio you are allowed to use. Check that your school has the right to play the recordings you load, particularly for performances in front of an audience or broadcasts. The cartwall only plays the files you give it.

10Troubleshooting

What you see	Why, and what to do
An amber bar says the audio engine is on standby	Browsers block sound until you click or press a key on the page. Click Activate Audio, or click anywhere. The bar then disappears.
I press a pad but hear nothing	Check, in order: the pad has audio (a green light, not grey); the speaker button at the top is not muted and the master volume is up; the computer's own volume; the output in Settings; the clip's in-point and out-point (they may have been trimmed to a silent part); the pad's Gain.
Sound comes out of the wrong speakers	Choose the device under Settings → Audio Output Device. If your browser does not offer the list, set the default output in the computer's sound settings.
The CLIP light is red, or the sound is distorted	The output reached full scale. Lower the pad's Gain or the master volume, check that Master limiter is ticked in Settings, and click CLIP to clear the light.
A hotkey does nothing	Check that you are on the right bank (keys work only for the bank on screen); that you are not typing in a box; that no window such as the editor is open; that the key has not been moved to another pad (open the editor to see); and that you are not holding `Ctrl`, `Alt` or `⌘`.
The Space bar doesn't stop the sound	Check that Space bar = STOP ALL is ticked in Settings, and that your cursor is not in a text box. `Esc` and the STOP ALL button always work.
A pad stops when I press it again, but I wanted it to restart	The pad is in Toggle mode. Open the editor and change Trigger Mode to Retrigger.
A different pad stopped when I started this one	The pads share a mute group, or the new pad has Solo on. Look for the G1 to G4 or SOLO badges.
Could not decode when loading a file	The browser cannot read that file, or it is damaged. Convert it to WAV or MP3 with an audio editor and try again.
All my pads are gone	You are probably in a different browser, user account or web address, or the saved data was cleared. Use Import and choose your latest backup (section 8.1).
The footer says SAVE FAILED	The browser couldn't store the data. Export a backup now, then check that the disk isn't full and that you are not in a private window. Contact your IT team if it keeps happening.
The page looks plain, or icons are missing	The cartwall couldn't download its fonts and icons. Check the internet connection and reload.
The browser asks Leave site?	The page is asking you to confirm because audio is playing or a save is still finishing. Choose Stay unless you really mean to leave.
A clip starts a moment late or the computer is slow	Close other heavy programs and tabs. Very long clips on many pads use a lot of memory (section 3.4); trim or shorten them.
Esc doesn't stop the sound in full screen	Browsers use `Esc` to leave full screen. Press `Space` or click STOP ALL.

11Reference

11.1Keyboard and mouse

Key or action	What it does
Pad's hotkey	Plays the pad in the bank on screen (behaviour depends on its trigger mode)
`Space`	STOP ALL (can be turned off in Settings)
`Esc`	Closes the open window; with no window open, STOP ALL
`F1` `F2` `F3`	Switch to bank A, B or C
`Enter` in a question window	Confirms the question; in the file-name box, exports
`Esc` in a question window	Cancels it
Click a pad	Plays it (or opens the file chooser if it is empty and unlocked)
Drop audio files on a pad	Loads them (first file on that pad, others on the next empty pads)
Drag a pad's grip onto another pad	Swaps the two pads
Click or drag on the editor waveform	Moves the nearer in- or out-point
Mouse wheel over the editor waveform	Zooms in or out at the pointer
`Shift` + mouse wheel over the editor waveform	Scrolls along the zoomed waveform

11.2Limits and ranges

Item	Value
Banks	3 (A, B, C)
Pads per bank	1 to 36 (12 to begin with)
Grid layouts	3×3, 3×4 (default), 4×4 (rows × columns)
Fade in / fade out	0 to 10 seconds each
Speed / pitch	0.5 to 2.0 (1 = normal)
Pad gain	−30 dB to +12 dB
Normalise target	Peak of −1 dBFS (within the gain range)
In and out points	At least 0.01 seconds apart; shown to 0.001 s
Greatest zoom	20 milliseconds across the waveform view
Mute groups	4, working across all banks
Ending warning	0 to 60 seconds (default 5; 0 = off)
STOP ALL fade	50 milliseconds
Level meter	Peak level, 12 segments from about −54 dBFS to 0 dBFS: green up to −18, amber up to −9, red above
Master limiter	Threshold −1 dBFS, fast attack (3 ms) and short release (0.1 s)
Undo window	About 7 seconds

11.3Glossary

Term	Meaning
Cartwall	A screen of large buttons (pads), each playing one audio clip. The name comes from radio's "cart" machines, which played jingles from tape cartridges.
Cart / pad	One button and the clip and settings that belong to it.
Bank	One complete wall of pads. This cartwall has three.
In-point / out-point	The moments where playback starts and ends within a clip. Also called trim points.
Trim	Cutting unwanted audio from the start or end without changing the original file.
Fade in / fade out	A gradual rise from silence at the start, or fall to silence at the end.
Mute group	A set of pads that cut each other off, so only one of them plays at a time.
Gain	A level change applied to one pad, measured in decibels (dB).
Normalise	Automatically adjusting gain so that the loudest peak reaches a set level.
dBFS	Decibels relative to full scale. 0 dBFS is the loudest level digital audio can carry; quieter levels are negative numbers.
Clipping	Distortion caused by a signal hitting the maximum level.
Limiter	A safety device that quickly turns down any peak above a ceiling.
Hotkey	A keyboard key assigned to play a pad.

AQuick reference card

Print this page and keep it by the computer.

Playing

Play a pad	Click it, or press the key in its [ ] badge
Stop everything	`Space` · `Esc` · red STOP ALL button
Change bank	`F1` A · `F2` B · `F3` C
Volume / mute	Slider and speaker button at the top right

Pad behaviour (set in the editor)

(none) Toggle	Press to start, press again to stop
RETRIG	Each press restarts from the beginning
HOLD	Plays only while held down
LOOP	Repeats until stopped
SOLO	Stops every other pad when it starts
G1 – G4	Pads in the same group cut each other off

On the pad

Pulsing, bright outline	Playing
Red flashing outline	Clip about to end (ending warning)
-00:12.4	Time remaining
∞ 00:03.1	Looping; time left in this pass
Green light / grey light	Has audio / empty

Editing and safety

Edit a pad	Cog on the pad
Precise trimming	Zoom buttons or mouse wheel over the waveform; `Shift` + wheel scrolls
Prevent accidents	Lock button at the top
Backup	Export (save the .harrison file somewhere safe)
Restore	Import, then Replace Everything
Wrong output device	Settings → Audio Output Device
No sound at first	Click Activate Audio or click anywhere on the page
Undo a delete	Undo in the message at the top right (about 7 seconds)