I have some CD's called "Practice Tracks". I bought them through Amazon. They're useful, though I like the Aebersold stuff better as they come with an excellent acompanying book too.
Here's a link to the Blues one for bass. I also have the Rock and Jazz Practice Tracks which are also pretty good. Just doa search on Practice Tracks at Amazon to see them all.
http://www.amazon.com/gp/product/B00...268215-4131836
You might also look into a product like Band In A Box from PG Music for your PC. Obviously more expenisve, but it's a good product nonetheless.
Good luck and have fun!!
