[GraemeJ]

Sometimes a hifi recording app is required because general audio recorder apps are intended for "speech memo" purposes.

I doubt there are any recording apps that are less than 16 bit. Use a sample rate of 44.1Khz and you have 'CD Quality' - which would be good enough for most people.

Overall sound quality depends on many factors, but a decent microphone and recording space run pretty much at the top of the list.

From the OP, I suspect that really high quality really isn't what is being sought here, just a means to record progress.