Doesn't quite work like that. MIDI's aren't technically sound files. Tell you what would work though cause i've done it many a time; You need a sound capture program. I use the one that comes with my Creative sound card but if you don't have one you wont have that software. Basically, all you need to do is have a sound recorder program, and then play the MIDI and record the sound in real time. It'll be in WAV and in perfect quality. Problem is finding a half decent program that is free or can be easily cracked, actually works, and has everything you want. Let me know if you do find one though cause I need one for my new computer cause that doesn't have a creative sound card.
Audacity works perfectly for what he said ^^^^^^^^^^^^^^^ its Free and works great download here >http://audacity.sourceforge.net/download/ open it and set the preferences for record input to your speakers, then before you record choose stereo mix, and record, play the MIDI file..stop recording..and wallah export as a .WAV or .MP3 (MP3 requires additional file) hope it helped
argh ... you probably have a better sound card, ay? or i have to tweak settings. i'm a total n00b when it comes to that stuff, like, audio technicalities.
yeah if you've ever read stories on Download.com or in PCMag or something, you'd know that Audacity is like the most popular, open-source audio editor, its definitely the way to go if you're looking for free software. You said you had trouble recording the .midi file? hrm lemme try one and see how it works. it normally just does a perfect clone (however, when I record something stereo, it only records it like mono, can't figure out why, any help on that would be appreciated). also, I belive Audacity can save to nothing but 128 kbps for mp3s, correct? anyways I suppose its your sound card, how old is it?