Location: England, United Kingdom
Firstly, I'll take this opportunity to introduce myself. I'm a good musician, and a reasonable singer. I sit in the back corner of the choir and sing second bass, trying to sing so low that I can make the plastic chairs vibrate. Now, I say I'm a good musician, but I'm not a keyboard player. This means that while I can sight-read quite adequately, I can't practice at home with a keyboard. I can play a keyboard one finger at a time, but this is where my keyboard skills end.
About 6 years ago, I started to use music software to create practice mp3 files. This means that when I record my practice files, I have the bass at normal volume, and I play the other parts at half-volume, so they are still audible, but in the background. Because I'd already typed all the music in, it was no extra effort to produce files for everyone in the choir. Because our choir mainly sings each Christmas (when the numbers are swollen by a lot of eager part-timers), this has become an invaluable aid for our choir. Our choir master does insist that we stop using the mp3 files for practice purposes around the middle of November, when all our note-bashing should be complete.
Because I was doing various bits of music each year, I decided I could offer this service world-wide (for a nominal fee), and so set up a web-site. I do get orders (very occassionally), but I was wondering if anyone needs any practice files for their choir. My web-site is www.4part.webs.com and I've recently started to put some already recorded music onto https://choirpractice.bandcamp.com/