I'm using a VGA CRT monitor here with that VGA dongle. This thing is great for Workbench and I have made a custom double NTSC driver which gives me 672x562 in 94 hertz interlaced (there's NO flicker and it's faster than Productivity mode). Useless for 15Khz stuff, of course
If you want amazing quality, do a quick convert to ADPCM4. I've played them at 230kbs, 27400khz. (on a double scan screen, they will play back at 56khz).
It's better to convert them to WAV format. For double scanned screens they don't have to be down sampled (both 44Khz and 48Khz are not a problem). For 15Khz screen modes use SOX (or any other program that offers high quality down sampling) on the peecee to down sample to 28Khz. That sounds quite good (as long as you have a calibration file).
Anyway, don't use 4 bit ADPCM, it's too lossy. Use 8 bit ADPCM (very good) or 16 bit WAV, and never let the music player do the down sampling. High quality down sampling is probably not what those players do (it's beyond the scope of the players, and it's quite heavy on the cpu), use proper high quality down sampling.
