LineListen Support

LineListen plays a hardware audio input through your current macOS output. It requires macOS 15 or later and a compatible audio input.

Get started

• Connect your audio input to the Mac.
• Select your speakers or headphones in macOS Sound settings or Control Center.
• Open LineListen from its joining-lines icon in the menu bar.
• Choose the input and press Start. Allow microphone access when macOS asks.
• Adjust volume, mute, and stereo or mono channels as needed. Closing the panel leaves monitoring running.

No sound?

Check that the correct input is selected, monitoring is started, mute is off, and both the app's volume and your system output volume are turned up. Confirm that the source device is supplying audio. The input meter can still move while LineListen is muted.

If the input is missing, reconnect it and press Refresh. Permission settings are in System Settings → Privacy & Security → Microphone. macOS uses this permission for USB audio interfaces too; LineListen does not create recordings.

Choose the output

LineListen follows the output selected in macOS. Change it in Sound settings or Control Center.

Buffer size and delay

The Mac and audio devices determine which buffer sizes are available. “In use” means your request matches the active buffer. “Device limit” means the route is using another size. The displayed milliseconds describe one buffer, not the complete delay from input to speakers.

Try a smaller buffer to reduce delay. Raise it again if playback becomes unstable. Wired headphones or speakers avoid the additional delay introduced by Bluetooth. There is no universal minimum that works with every device.

Menu bar indicators

• Plain icon: idle or reconnecting.
• Green dot: monitoring is running.
• Orange ring: monitoring is running but muted.

Keyboard shortcuts

Open Shortcuts in the panel to record your own combinations or restore defaults. The defaults use Control–Option–Command with M for mute, Down Arrow for volume down, and Up Arrow for volume up. Volume changes by five percentage points and preserves the mute state.

A shortcut already used by macOS or another app may need a different combination.

Hardware inputs and microphone feedback

LineListen monitors hardware audio inputs. It does not capture individual apps, install a virtual audio driver, or record files.

Use headphones when monitoring a microphone near your speakers. If you hear feedback, mute or stop monitoring.

Contact

Email support@flaviothomi.com with your macOS version, input device, output device, requested buffer size, and a short description of the problem. Include any error message shown by LineListen. Audio recordings are not required.