I did a search but couldn’t find anything. I think it would be helpful for everyone (a sticky?) if someone could list the estimated number of hours each Flash Drive size can record in 18 multi-track mode:
16GB = X hours
32GB = X hours
64GB = X hours
128GB = X hours.
The maximum file size on FAT32 is 4 GB. Qu-Drive audio data rate per track is 8.24 MB / minute (144 KB / second). This would allow a maximum recording time of roughly 8 hours. For 18 tracks you would need 72 GB drive capacity for the maximum recording time.
I did see that reference in “Understanding Qu-Drive and USB Devices:”, but it was unclear to me. I do have a better understanding now that I looked at your math.
The only remaining question I have is: I’m not sure what influence the maximum file size on FAT32 being 4GB has, if any?
The 4GB filesize limit restricts maximum take length to 8 hours for multitrack recordings and 4 hours for stereo recordings. That’s why a 128GB drive can hold one 8 hours recording (limited by file size) plus one 6.2 hours recording (limited by remaining space).