• 99 slots — each with its own name (12 characters, exactly the width of the display), its own tempo, rhythm, and settings like One Shot: play once and stop — backing-track mode.

• Sound without compromise — loops are stored as 32-bit float WAV.^[1] No "good enough for a pedal": a bounce from your DAW comes back as the same bounce.

• A drum machine — rhythm patterns per slot and a count-in: the pedal can count one bar before the loop or before recording (two different parameters — PLAY COUNT and REC COUNT — and it will make you pay for confusing them).

• USB — the pedal can pretend to be a flash drive (STORAGE mode: a plain FAT card with plain WAV files inside) and speaks USB-MIDI.

• Slot names. Twelve characters, entered by scrolling a knob through a character list. Twelve characters. Ninety-nine slots. Do the math, then go get yourself some catnip.

• The tempo is guessed. On WAV import the pedal assumes every loop is a power-of-two number of bars: 4, 8, 16… If your track dared to be 6 bars long, the tempo comes out wrong and the built-in rhythm drifts away from the music. Silently.

• 16-bit WAV is silently dropped. Upload a file in the wrong format and the pedal simply does not see it. No error, no explanation. The slot stays empty; direct your questions to the universe.

• macOS plants landmines. Copy a WAV onto the mounted pedal with Finder, and an invisible sidecar file (._*, AppleDouble) quietly lands next to it.^[2] On the next boot the pedal may greet you with LOOPER DATA READ ERR and refuse to start — without explaining why.

We are musicians and engineers, we have a cat, and we took this personally. So we took the RC-5 format apart down to the byte — every fact pinned by tests against a real pedal — borrowed Tone Studio’s single useful SysEx trick, and built LooperCat: a free, open-source loop manager for the BOSS RC-5 on Mac, Windows, and Linux.

What it does:

And the cat breaks nothing: every operation travels with a backup, and foreign cards (RC-500/505/600 — a similar but different data dialect) are politely turned away at the door instead of "it will probably be fine".

If you love the terminal, there is rc5cat: our own CLI on the same knowledge of the format — that is where it all started. But the native LooperCat has gone much further.

LooperCat is an independent project: not affiliated with or endorsed by the pedal’s manufacturer; "BOSS RC-5" and "BOSS TONE STUDIO" are used nominatively, to indicate compatibility.

With LooperCat — a free, open-source Boss RC-5 editor for Mac, Windows, and Linux: names are typed on a real keyboard (12 characters — exactly the width of the pedal's display), and all 99 slots are visible in one table. The official BOSS TONE STUDIO for RC cannot rename slots.

Bounce from your DAW → LooperCat → Push WAV here… The file is converted to the pedal's native format on the fly (32-bit float WAV: sample rate, channels, header bytes). Switch on One Shot and Play Count-In — and the backing track is stage-ready: the pedal counts one bar and plays the track exactly once.

On WAV import the pedal assumes the loop spans a power-of-two number of bars (4, 8, 16…). Any other loop gets a wrong tempo, and the built-in rhythm drifts away from the music. LooperCat writes tempo and bars coherently — the very arithmetic the pedal skips.

The pedal could not read the card's data. A frequent cause on a Mac is the invisible macOS sidecar files (._*, AppleDouble) that Finder silently plants when you copy WAVs onto the mounted pedal; another is damaged service structures on the card. LooperCat sweeps the invisible files away and checks the card with a built-in doctor; upload loops through it and the message never comes up.

It does — minimally: BOSS TONE STUDIO for RC exists, works with the RC-5, and in practice does one thing — uploads a WAV to the pedal. No slot names, no tempo, no playback, no card diagnostics. For everything else there is a free alternative — LooperCat.