Sonlit

Sonlit Lock Sound

Pick the sound your car makes when you walk away

Choose a sound file you own, trim the part you want on a waveform, and get a file named exactly LockChime.wav and small enough for the car, built on your device and ready for a USB drive.

Not built yet, but next. This is the first tool I am writing, because it is the smallest complete test of the whole loop: pick a file, process it in the browser, get it onto a stick, hear it in the car. Everything the light show designer needs later is proved out here first.

What it will do

One page, four decisions, one file

  1. Pick a sound

    Whatever your phone or computer will hand a browser: mp3, wav, m4a, aac, aiff, flac. Voice memos work, which is how most of the good ones start. If you have nothing to hand there are three starter chimes I synthesise in the browser from scratch, so there is no sound library involved and nothing borrowed.

  2. Trim it

    A waveform with two drag handles and a play-selection button, plus typed start and end times beside them so the whole thing works from a keyboard. The default selection is the first three seconds, which is usually about right for a chime.

  3. Set the few things that matter

    Peak normalise so it is actually audible outdoors, a short fade in and out so it does not click, and mono or stereo. A live readout shows the projected file size in bytes against the limit, and turns red before you can make a file the car will not take.

  4. Build it, then save it

    Build runs the work, then a separate Save or Share button hands you the file — two taps rather than one, because phones will not let a download start after asynchronous work has run. The file is always named LockChime.wav. You never type a name or an extension.

Nothing you pick is uploaded. The decode, the trim and the wav writing all happen inside the browser tab, and the file is saved straight out of it.

What is actually known

Two published facts, and a lot of folklore

Tesla has said exactly two things in writing about a custom lock sound: what the file is called and how big it can be. Everything else circulating online comes from owners experimenting. This page keeps the two apart, and so will the tool.

Published by Tesla

Documented
File name
LockChime.wav
Maximum size
under 1 MB
Vehicle software
2023.44.25 or newer
Hardware
Pedestrian Warning System
Menu
Toybox > Boombox > Lock Sound
When it plays
locking from outside

Tesla names the file only in one release note, and the owner’s manual only says the Lock Sound menu exists. That is the whole documented surface.

Reported by owners, not yet confirmed by me

Unverified
Where the file goes
drive root, or a Boombox folder
Length before it is cut off
about 5 s
Sample rate
44.1 kHz, or 22.05 kHz
Menu entry label
USB

Third parties disagree with each other on every row above. I am checking each one on a real Model Y before the tool ships, and whichever answer the car gives becomes the default while the other stays available as an alternative.

Where the size limit lands

Sonlit guards at 1,000,000 bytes, because Tesla writes “< 1 MB” without saying which megabyte it means, and the smaller reading is the safe one. At 16-bit PCM that ceiling works out to roughly 11.3 s of mono at 44.1 kHz, 5.6 s in stereo, or 22.6 s of mono at 22.05 kHz. The tool defaults to a five second cap with an option to go longer, clearly labelled as untested, and shows you the arithmetic as you drag the handles.

Today

What is worth doing here now

Check the car qualifies

Open Toybox on the touchscreen. If there is no Boombox app there, your car cannot take a custom lock sound at all, and no tool will change that. Boombox needs the Pedestrian Warning System speaker, and the lock sound needs software 2023.44.25 or newer.

Get a drive ready

A cheap stick of 32 GB or less, one partition, formatted exFAT or FAT32. Not your Dashcam drive. The USB guide covers the whole thing, including what to do on a 2025 Model Y where the glovebox port is already occupied.

Find your sound

Something you own, three seconds long, that survives being played through a small outdoor speaker. Record it now while you are thinking about it — a voice memo is a perfectly good source and it is already a file the browser can open.

Questions

Things worth knowing before you start

Can I use a song from Apple Music or Spotify?

No. Streaming tracks are protected, and a browser cannot open them however you point it at them. You need a file you own outright: a purchased download, a recording of your own, a voice memo. The tool takes what your device will hand it and says plainly when a file is one it cannot read.

How do I know whether my car can do this at all?

Look for Boombox in Toybox. Tesla states that Boombox is only available on vehicles fitted with the Pedestrian Warning System speaker, and that entertainment options vary by market, build date and configuration. If Boombox is missing, a custom lock sound is not available on that car. If it is there but there is no Lock Sound entry, check the software version against 2023.44.25.

Where exactly on the drive does the file go?

Tesla’s wording is “onto a USB flash drive”, which reads as the top level, and that is what Sonlit will offer first. Some owners report it working from a folder named Boombox instead. Until I have watched a real Model Y accept one and reject the other, the tool will render steps for both placements and label which is Tesla’s wording and which is an owner report.

Does it play when I unlock the car, and can I change the volume?

Tesla documents the sound for locking the car from outside and says nothing about unlocking or about volume, so I will not promise either. Boombox as a whole only operates while the car is in Park, which is also when a lock chime would play. If the car turns out to do more than the documentation says, I will write that down as an owner report and mark it as one.

Can one drive hold my lock sound, a light show and my Dashcam footage?

Tesla never says. The Boombox documentation says a drive holding custom sounds cannot be shared with Dashcam, and the light show documentation says a light show drive must not contain a top-level TeslaCam folder, which points the same way. Owners report combined and partitioned drives working. My advice is the boring one: use a separate cheap stick for this and leave the Dashcam drive alone.

Acceptable use

  • Use your own recordings or music you have rights to.
  • No public sharing of copyrighted audio through these tools.
  • No use on or near public roads.
  • No automated or bulk use of the storage or email features.

The tool asks you to confirm you own the recording, or have permission to use it, and that you are making the file for your own car. Sources are on the credits page.