A music visualizer that hears your Mac's system audio.

Everything your Mac plays leaves through its audio output, and that is where LIQUIDWAVE listens. Spotify, the Music app, a YouTube tab, a DAW or a game all reach the visualizer the same way, with nothing to install and nothing to reroute. This page explains how the capture works on macOS 14.2 and later, what it can't hear, and what to do when the picture sits still.

Heard through macOS, not a driver

For a long time, a Mac app that wanted the system's sound needed a virtual audio driver: an extra output device you installed, chose in Sound settings and sent your music through. macOS 14.2 added Core Audio Taps, a way for an app to ask the system for a copy of what is playing. LIQUIDWAVE is built on it and needs nothing else.

With the source switch at the bottom of the window on System, LIQUIDWAVE opens one tap on the whole system mix and joins it to your current output inside a private device only LIQUIDWAVE can see. Switch to another source or quit, and the tap and the device are torn down. Your output stays the one you chose, and you keep hearing everything as before. The tap takes a copy. It doesn't reroute the sound.

One permission

The first time the tap starts, macOS asks whether LIQUIDWAVE may record system audio. System needs no other permission. The sound is mixed down to one channel and analyzed as it arrives. Nothing is recorded, saved or sent anywhere.

macOS gives apps no way to check that permission in advance, and a declined tap doesn't report an error. It simply delivers silence. That is why LIQUIDWAVE watches for silence instead, as described below.

Turn the player down, and the picture holds

A tap hears each app after its own volume slider. Spotify at half volume arrives about 20 dB down, and many people keep a player's slider low while the Mac's volume or their headphones do the work. Read raw, that would look like a very quiet song.

So the capture passes through a leveler before the analysis sees it, and the leveler only ever raises the level. Quiet playback is lifted toward a steady −18 dBFS, by up to 40 times, which recovers a slider set to about a quarter. The lift rises over a second or two and backs off within about a tenth of a second when the music gets loud, and a stream already at that level passes through bit for bit.

Below −66 dBFS the leveler treats the sound as silence and holds its gain. The gap between two tracks stays a gap, and the next song lands at the level the last one settled on.

Headphones in, headphones out

The tap is tied to the output that was in use when it started. Plug in headphones, connect AirPods or pick another speaker, and macOS announces the change. LIQUIDWAVE waits a quarter of a second for a chain of device changes to settle, then rebuilds the tap on the new output.

Protected streams stay silent

macOS silences a DRM-protected stream for every capture app, LIQUIDWAVE included. This is the operating system enforcing the content license, and no setting in LIQUIDWAVE can change it. Purchased and DRM-free tracks come through as usual, and the Apple Music guide covers the Music app in detail.

Listen Mode can still see a protected stream. It hears your speakers through the microphone, so switch the source to Listen and play the song out loud.

When the scene sits still

When System has heard nothing for four seconds, a small lock badge appears in the top-right corner of the window. Hover over it, and it reads "LIQUIDWAVE isn't hearing anything", followed by: "If music is playing, allow LIQUIDWAVE under Screen & System Audio Recording in System Settings → Privacy & Security (on older versions of macOS, Microphone), then press Retry. DRM-protected streams stay silent for every capture app; switch to Listen to see those."

Below that, Open System Audio and Open Microphone take you to those panes, and Retry starts the tap again. The badge goes away by itself as soon as sound arrives.

A paused player sounds exactly like a missing permission, so the badge can't tell them apart. Work through it in order:

1. Play something unprotected, a video in a browser tab for instance. If the scene moves, the capture is fine.
2. If nothing moves at all, allow LIQUIDWAVE in System Settings and press Retry.
3. If only certain songs stay still, they are probably protected. Switch to Listen.

A silent System source keeps the picture still on purpose. Ambient Auto plays only while no source is running, so a still scene under System means the capture hears nothing.

What it doesn't do

It doesn't pick one app. System hears the whole mix. A notification sound, a call or a game in the background joins the picture, so pause what you don't want to see.

It can't hear protected streams. That silence comes from macOS, and Listen Mode is the way around it.

It only hears what the Mac plays. Music playing on another device, such as a speaker you control with Spotify Connect, never passes through the Mac.

It needs macOS 14.2 or later. Core Audio Taps don't exist before that, and LIQUIDWAVE has no driver to fall back on.

Set it up

1. Download LIQUIDWAVE and drag it to your Applications folder.
2. Open it and allow system audio recording when macOS asks.
3. Play anything. Leave the source on System, or choose System Audio from the menu bar icon (⇧⌘1).