Previously I used free services on the internet as an alternative to freeware programs. I liked one of them in particular, solmire.com. But quantity of midis was constantly growing and it became awkward to upload and download files every time when I wanted to convert them. It also ate much traffic. Then I found a program that could convert many midi files in a short time. Now I use it constantly
. There is even a tutorial: How do I convert MIDI to MP3.
mymusictools.com/articles/how-do-i-convert-midi-to-mp3.htm