I was able to fit about 60 MB per channel on a 90 min audio cassette [1]. The bias frequency of that particular deck was about 60 kHz. This means bypassing the

I was able to fit about 60 MB per channel on a 90 min audio cassette [1]. The bias frequency of that particular deck was about 60 kHz. This means bypassing the recording circuitry could lead to much higher data rates. 1.: https://news.ycombinator.com/item?id=28193079 https://news.ycombinator.com/item?id=28193079