The Soul of Cassette Tapes
A trick for breathing life into digitally recorded material is to incorporate imperfections from older recording technologies, such as analog tape or vinyl records.
With this noise generator, you can add a vintage cassette player vibe to your digital music. To make it sound realistic, set the levels so that the hiss becomes just audible in the quietest passages of your music. You may be surprised by an impression that the sound quality of poor recordings has improved. It is because you may be adding frequencies that are missing, even though they are present only as a hiss.
Cassette tape hiss is a beautiful source of analog noise too, and can be used on its own as a kind of white noise generator. Due to the nature of tape playback, tiny fluctuations will affect the sound, breathing life into the otherwise static noise.