Questions,
answered once, honestly.
Everything most people write in about — what the meter modes measure, what macOS asks for and why, how the strip behaves around fullscreen apps, and where the app falls short. If something isn't here, the inbox is the next stop.
General
The usual first questions about what the app does and what it doesn't.
Does flexMeter record my audio? +
No. It reads levels from your input device in real time and does not record, store, or transmit any audio. macOS requires microphone permission for any app that opens an audio input — flexMeter installs a tap on the input device to calculate levels, and that's all.
Can I use it with a USB audio interface? +
Yes. flexMeter detects every input device macOS sees via CoreAudio — built-in mic, USB interface, Thunderbolt interface, virtual audio device. It supports 1 to 8 channels per device.
What happens if I unplug my audio device while it's running? +
flexMeter notices, switches the engine over to the system default input, and shows a brief status message. It does not crash, quit, or freeze the strip.
Metering
What the three modes actually measure, and how to read them.
What's the difference between VU, PPM, and LUFS? +
VU (300ms integration) is slow and reads average loudness — it's what broadcast uses for voice. PPM (IEC 60268-10 Type I) has a fast attack and slow return, so it catches short transient peaks a VU reads past. LUFS (ITU-R BS.1770-4) uses K-weighted gated loudness and is the measurement streaming platforms actually check against — momentary, short-term, and integrated readings all update in real time.
What do M, S, and I mean in LUFS mode? +
M (Momentary) is loudness over the last 400ms — it reacts almost immediately. S (Short-term) is loudness over the last three seconds, which smooths out brief fluctuations. I (Integrated) is the gated loudness across the whole measurement period — the number to match against a platform target. Hit Reset Integrated to start a new measurement at the top of a take.
How do I know if my levels are right for YouTube, Spotify, or podcasts? +
Switch to LUFS, pick the preset that matches your target — YouTube/Spotify (-14), Apple Music/Podcast (-16), or Broadcast (-23). A cyan reference line appears on the strip at that target level. Aim to keep your integrated (I) reading near it.
What do the meter colours mean? +
Green below -12 dB (safe). Yellow between -12 and -6 dB (warm). Red above -6 dB (approaching clipping). Peak hold indicators turn red above -6 dB too, so a glance tells you the same story.
Display and interaction
Where the strip lives, how it moves, and how it behaves around other windows.
How do I move the meter to a different screen edge? +
Three ways: press Command-Shift plus an arrow key, long-press the strip for half a second and drag it, or use the Position picker in the menu bar settings or the right-click context menu.
Does it appear over fullscreen apps? +
Yes. The panel uses macOS collection behaviors that let it sit above fullscreen apps and follow you across every Space. That's the entire reason the app exists.
Can I click through the strip? +
Yes. By default, mouse events pass through to whatever is underneath. Right-clicking opens the context menu; long-pressing enables drag mode temporarily. Nothing else gets intercepted.
Can I use it on a second monitor? +
Yes. When multiple displays are connected, a display picker appears in settings. Pick the screen you want. The choice is remembered, and the strip re-positions itself when you rearrange your displays.
System
Requirements, honest limits, and a few small things worth saying out loud.
Does flexMeter appear in the Dock? +
No. It runs as a menu bar agent. No Dock icon, no app window — every control lives in the menu bar dropdown and the right-click context menu.
What macOS version do I need? +
macOS 26.4 (Tahoe) or later, on Apple Silicon (M1 or newer).
Any known limits? +
flexMeter meters input devices only — it doesn't read system audio output or per-application audio. The integrated LUFS implementation uses incremental gating rather than a full relative-gate recomputation across the whole history. Neither one affects a normal recording session; both are listed here because you asked honestly.
Didn't see your question?
We read every email that comes in and reply to most of them. If you've got a setup we should test against — a specific interface, a strange audio routing rig, a broadcast spec we haven't thought about — send it over.