Tracks streamed on your computer play in up to 320kbps MP3. Tracks downloaded using the software play at 192 Kbps MP3. Occasionally these tracks are not available in high quality and will play at 64 kbps.
All tracks streamed and downloaded on your mobile app will almost completely play at 320 kbps, though you can set them to play at 192 kbps or 64 kbps to reduce your data usage. Again some tracks for download are not available in high quality and will play at 192 kbps or on rare occasions in 64 kbps.