Maybe TURBO expansion was needed I don't know. We just had that soft at home and I tried it a little, using some audio cassetes and replayed it back... IIRC I looked into the code of that small program and it used only 1bit sampling.. reads 0 or 1 from SIO and then replayed it back.. zero volume or full volume, nothing more. With 15,6kHz (change every line... 312x50) it's almost 2kB per second so as I said before, it played around 20+ sec of music.