A free app for Mac
SoloVolume
A real volume control for your Focusrite Scarlett Solo.
SoloVolume gives a Focusrite Scarlett Solo, or any output macOS gives no volume control, a working menu bar volume slider, mute and keyboard volume keys, without installing an audio driver.
- macOS 14.2 or later
- Apple silicon and Intel
- Free and open source
- Signed and notarized by Apple
Version 1.1.0
Why I built it
It started with something I needed.
macOS greys out the volume control for a Scarlett Solo, because the interface doesn’t offer one. I was paying for a big audio utility only to turn my speakers down.
So I built the one piece I needed: a volume slider and working volume keys, with nothing installed underneath macOS.
What it does
What SoloVolume does
- A volume slider and mute
- Right in the menu bar, for the Scarlett Solo or any output with no volume control of its own.
- Your volume keys work again
- The keyboard volume and mute keys control the device, with the on-screen level you expect. Hold Shift and Option for fine steps.
- Stays out of the way
- When you switch to AirPods or another output, your keys go back to macOS as normal.
- Survives unplugging
- Unplug the interface and plug it back in, and SoloVolume picks it up again. It can also launch at login.
- Smooth, not clicky
- Volume follows a natural curve and changes are ramped, so turning it up or down never clicks.
- No driver to install
- It works with what macOS already has, so there is nothing to install or remove beneath the system.
Private by design
It stays on your Mac.
- SoloVolume does its work on your Mac. No accounts, no analytics, no tracking.
- The audio it handles goes straight back out to your device a few milliseconds later. It is never saved, recorded or sent anywhere, and only audio headed to that device is touched.
- The volume-key listener only sees media keys like volume and mute, never what you type.
- Your interface’s microphone inputs are never opened.
- The only time it goes online is a once-a-day check for updates, and every update is signed so it can’t be forged.
Permissions, asked only when a feature first needs them
- System Audio Recording, so it can pass the audio through with your volume.
- Accessibility, only if you want the volume keys.
How it's built
For the technical reader.
Written in Swift on Core Audio process taps (macOS 14.2 and later). A tap captures the audio other apps send to the device, and a private aggregate device plays it back with gain on a cubic curve, ramped per buffer so changes never click.
Every release is signed with my Apple Developer ID and notarized by Apple, and runs with the hardened runtime, so other software can’t slip code into it. Updates come through Sparkle, and each update is signed with the app’s own EdDSA key and checked against it before anything is unpacked.
- Core Audio
The full code is on GitHub, MIT licensed.
Ready to try SoloVolume?
SoloVolume is not affiliated with Focusrite. Scarlett is a trademark of its owner.