Track 1 is the name used for the game data stored in the GD-ROM's for the Sega Dreamcast. It is presented as an audio file, however many CD-readers and audio players tend to skip this track as it has over 1 GB of unaudible data, thus skipping this track. Then it will play Track 2, which provides warnings of "not playing this disc on a normal cd player". Using special techniques, there have been sucessful tries of playing track 1 on a regular cd player.
When played, track 1 will play a loud garbled, static-like noise which most cd players can't turn down that will run for approx 112 minutes. Modern and new cd players will either skip to the next track or play the track, with no noise.
However, since such loud and high freq noises are present when played, it is probable that the audio will damage cd speakers.