Luma Technical Details: format, signal path, spectrogram
Playback, updated
If you want to know exactly what's in a file and whether Luma plays it unchanged, Technical Details show you everything at a glance. They're available since Luma 1.6 on iPhone and iPad and since Luma for Mac 1.1.
Turn on and open
Technical Details are hidden by default. Turn them on under Settings › Playback › Advanced › Technical Details, and on the Mac likewise in the Playback section of the settings.
- iPhone and iPad: touch and hold a song and choose Technical Details. For the playing song, tap Details at the bottom of the full player. On the iPad and the unfolded iPhone Duo they open at full height right away.
- Mac: right-click a song › Technical Details. For the playing song there's a button of its own in the playback bar at the bottom, next to AirPlay. The window that opens there follows whatever is playing, and closes with a click outside it or with Esc.
What's in the file
The File section reads its values straight from the music file:
| Row | What it shows |
|---|---|
| Format | The codec, such as FLAC, Apple Lossless, AAC, MP3 or Opus, and whether it's lossless or lossy |
| Sample rate, bit depth | For example 96 kHz and 24 bit. For FLAC and Apple Lossless, Luma reads the bit depth from the file itself. |
| Channels, bitrate, duration | Mono or stereo, the data rate and the exact length |
| File size, file type, encoder | How big the file is, its extension and, if it's recorded, the program that created it |
| Cover | The size of the embedded artwork in pixels |
Below that, the Loudness section shows the measured loudness in LUFS, the peak level and how much Luma raises or lowers the song when it normalizes the volume. The Library section shows plays, listening time, when you last played the song and when you added it, plus where the file is stored.
The signal path
For the song that's playing, Luma shows step by step what happens to the sound on its way to your headphones or speakers. The values are read again every second, so you see right away when you switch the output device, for example.
- Source and decoder: what's in the file and which format Luma converts it to for playback.
- Sample rate: whether the rate stays as it is or is converted for the output device, for example from 96 to 48 kHz.
- Equalizer, normalize volume, volume in Luma: whether these stages step in, and by how much.
- Output and latency: the device with its sample rate, and how long the sound takes to get there.
- Processing: sums up which steps change the sound. If it says None, the music leaves your device exactly as it is in the file, see Bit-perfect.
- Status: whether the song is playing, a cross-fade is running or the next song is already lined up gapless.
For a song that isn't playing, this section only says Only while playing.
The spectrogram
At the very top, Luma shows a live spectrogram of the playing song. Time runs from left to right, low frequencies sit at the bottom and high ones at the top, and the louder a range, the stronger its color. What you see is the sound as it comes out of the equalizer, so with your sound settings. With every new song the picture starts over, and it only runs while the view is open and Luma is in front.
An MP3 or AAC made from a lossless file often shows up in the spectrogram as a sharp edge at 16 to 20 kHz with nothing above it.
Still have a question or found a mistake? Email hello@suenavus.com.