Running Apple Music on MacOS? For hi-res enthusiasts looking to get the very best from Apple’s lossless content, the gotcha is an absence of automatic sample-rate switching. Unless we are extremely vigilant, the audio data that we pulled from Apple’s servers isn’t necessarily that which reaches our DAC. Why? MacOS will adjust the data’s output according to the settings specified in the Audio MIDI Setup app.
It’s a game of cat and mouse where:
- audio samples are interpolated by the operating system when the incoming sample rate sits below the Audio MIDI app’s output setting. This is called upsampling.
- audio samples are thrown away by the operating system when the incoming sample rate sits above the Audio MIDI app’s output setting. This is called downsampling.
Upsampling and downsampling are collectively referred to as resampling. Let’s exemplify.
If we hit play on, say, a 192kHz hi-res lossless stream but the Audio MIDI Setup app is set to 44.1kHz, we lose data. If we hit play on a 44.1kHz file but the Audio MIDI Setup app is set to 96kHz, we gain dummy data (and arguably lose again). Resampling can subtly alter the sound of a stream heard on a more resolving hi-fi or head-fi system.
Only when no resampling takes place do we have what is known as ‘bit-perfect playback’. And this is only achievable on MacOS by manually specifying the Audio MIDI Setup app’s sample rate on a track-by-track (or album-by-album) basis.
That is, until now…
Vincent Neo’s LosslessSwitcher app “switches your current audio device’s sample rate to match the currently playing a lossless song on your Apple Music app, automatically.”
Once installed and running, the app runs in the menu bar at the top of the screen, next to the clock. Lossless Switcher reads the sample rate of the incoming Apple Music stream and then automatically sets the corresponding sample rate in the Audio MIDI Setup app.
Vincent Neo warns that “there may be short interruptions to your audio playback, during the time where the app attempts to switch the sample rates.” He also says that his app has yet to be tested on an M1 Mac.
Lossless Switcher is available free of charge from Neo’s Github repository.
Further information: Lossless Switcher