The track combines double bass, vocals, violin and other instruments. On balanced headphones no part of the range is louder.

Prepared sounds that test one thing at a time.
Start at a moderate volume.
Noise band, Hz
Each page plays a track chosen for one part of the sound, followed by sound effects that test that part on its own. Switch between them with the tabs above.
To check that the left and right channels work, use the left and right headphone test.