There has a been a search query for pink noise burn-in.
Here’re some tracks off our Audiotest CD. The CD is freely downloadable.
Pink Noise, 30 seconds;
Digital Silence, 30 seconds;
Digital Silence, 5 minutes;
An example playlist could be set up to play 20 minutes of pink noise followed by five or two minutes of silence (keeping headphones stressed with pink noise constantly can damage them, though this also depends on how gentle the driving amp is), looping.
The files are in FLAC format - here’s the FLAC Download page with links to software capable of working with FLAC files. For Windows, the Foobar2000 player is highly recommended.
