This came up in a chat at work, and it's got me curious. I've done lossless vinyl rips to preserve stuff I can't find good digital copies of (the Loving Awareness album for example) which came out to about half a gig, but I think that's more to do with the unreasonably overkill sample rate I was using (I know better now!) rather than any meaningful way of measuring data storage because 192 kHz FLAC is going to have a far better noise floor than vinyl.As vinyl records are fundamentally analogue we need a digital modulation technique, apparently vinyl has about 18 kHz of bandwidth available so perhaps we could employ several frequency-shift keying channels? Could we do better than audio frequency shift keying^1 since vinyl records have more bandwidth available than the phone lines this is used on?