Music
System Output · AirPods Pro
Mac volume control, app by app.
Semper is an open-source per-app volume mixer for macOS. Turn down a browser, route a call to AirPods, apply an EQ to Music, and leave everything else alone.
AirPods Pro
100% max · boost unavailable
AutoEQ
76%
Applications
▶ Test Sound
Meet
AirPods Pro · Routed
Safari
System Output · AirPods Pro
Try the mixer Drag a slider or mute an app.
01
Source available now. A packaged public release has not been published yet.
Your Mac is playing three things.
macOS gives all of them one slider.
Music
Too quiet
28
Meet
Too loud
82
Safari
Not needed
64
SEMPER MIXER
3 CHANNELS
Music
68
Meet
42
Safari
0
Changing the master level cannot fix the mix. Semper controls each audio process before it reaches the output.
Split the signal. Keep the context.
Semper identifies the process producing audio, gives it a level, and lets it follow the default output or take its own route.
App by app
Volume, mute, boost, EQ, balance, and output live beside the app they affect.
Route with intent
Send a call to headphones and music to your speakers.
Stay where you are
Bind global shortcuts, use media keys, or drive the popup from the keyboard.
More than volume. Shape the sound, not the system.
A 10-band EQ works per app. AutoEQ can correct supported headphones per device. Loudness compensation follows ISO 226 contours at low listening levels.
APP EQ
Music
Active
+120 dB-12
32
64
125
250
500
1k
2k
4k
8k
16k
10 bands
Final peak limiter at -1 dBFS
No pretend controls. Semper listens to the hardware, too.
A MacBook speaker, USB interface, display, and Bluetooth headset do not expose the same controls. Semper checks the active path and only shows what it can actually change.
Studio DisplayDisplayPort
Ready
- DDC volumeAvailable
- BalanceAvailable
- Software gainOptional
AirPods ProBluetooth
Ready
- Hardware volumeAvailable
- AutoEQAvailable
- BalanceHidden
Capability-aware controls are not decoration. They keep the interface honest when the audio path changes.
Release status
Packaged builds are still being prepared.
There is no public Semper DMG yet. The source, tests, and build instructions are open now. Signed and notarized downloads will appear on GitHub Releases when they are ready.
-
01
Inspect the source
Review the Core Audio engine, SwiftUI app, tests, and guides.
-
02
Build it locally
Use Xcode and follow the repository build instructions.
-
03
Watch for a release
Use GitHub's Watch control to follow tagged builds.
Do not install a Semper DMG from an unofficial source. Public release notes will include the supported macOS version and test status.
Built in the open.
Open source. Join the work.
Semper is actively looking for contributors. Help with Swift, SwiftUI, Core Audio, tests, accessibility, device compatibility, and technical writing. The source, tests, guides, and issue tracker are open under GPLv3.
Find a starter issue
semper / source
Swift
├─Audio
├─
ProcessTapController.swift
Process taps
├─
SoftLimiter.swift
Output safety
└─
AutoEQProcessor.swift
Headphone EQ
├─Views
└─
MenuBarPopupView.swift
Menu-bar UI
└─
SemperTests
Test suite
GPL-3.0
Native SwiftUI
Unit tested
Semper facts
What to know before you try it.
What is Semper?
Semper is an open-source macOS menu-bar app that gives each audio-producing app its own volume, mute, output route, and equalizer controls.
Does macOS include per-app volume control?
macOS Sound settings provide output-device selection and overall output volume. Some apps have their own controls, but macOS does not provide one system mixer with independent sliders for every app.
Does Semper record or upload audio?
No. Semper processes tapped app audio in memory on the Mac. The project does not intentionally save that audio to disk or upload it to Semper maintainers.
Can I download a stable Semper release?
Not yet. The source code and build instructions are public, but no packaged public release has been published as of July 31, 2026.
Can I contribute to Semper?
Yes. Pick a starter issue, read the contributor guide, and comment on the issue before starting a larger change.
Read the per-app volume guide or the Semper fact sheet.
Your apps are already separate.
Their volume should be, too.
Semper is an open-source project for making macOS audio control make sense. If that matters to you, join in.
curl -fL https://github.com/niharnm/Semper/archive/refs/heads/main.zip -o "$HOME/Downloads/Semper.zip" && open "$HOME/Downloads/Semper.zip"