How to · Sound
Read the Signal Path
What happens to the music on its way to your DAC, and what each light means.
Where to find it
- iPhone and iPad: Now Playing › the Signal Path tab, with a coloured light beside it.
- Mac: the signal chain under the cover.
The Signal Path shows each step the track goes through: Source, Transport, Decoder, the app's processing or the equalizer, and Output. When the music plays on another device or a streamer, it adds that step too.
The lights
- Green, Sent bit-perfect: the original file or a lossless repack, no EQ, and the output runs at the file's rate, or DSD goes out over DoP. On a USB DAC, Sterio tells you what to check, such as Check your DAC: it should show 96 kHz. On a phone, keep the volume at maximum unless the DAC controls volume.
- Orange, Equalizer is on: the equalizer changes the signal.
- Red, Not bit-perfect: something converts it. Converted by the server (DSD to PCM, DST or a transcode), Compressed for Bluetooth (AirPods get AAC), or Resampled by the system, for example a speaker that plays at 48 kHz when the file is 44.1 kHz.
- Grey, Can't be confirmed: AirPlay, where the receiver sets its own rate, or an output that doesn't report its rate.
On another device
When the music plays elsewhere, you see that device's own Signal Path, as it reports it: Audio plays on … This is its Signal Path, as that device reports it.
Words you meet here are explained in the glossary.