Just got a Tascam CD-GT1 Guitar Trainer for my birthday. The dude at Guitar Center told my wife it would work great for bass too and he was right. It goes for 149.95 plus another 20 if you want a power supply instead of batteries. This is one great toy. You can slow down a CD without changing pitch, change pitch without changing tempo, and loop a CD, a song, or just the riff you want to learn with just a touch of a button. You plug your bass into it and then you hear the CD and your bass through headphones, or you can run the line out to speakers. I ran it into the input of my SWR Workingman 12, switched the tweeter on and it sounds fantastic. A very useful toy for playing along with a CD privately or looping a section of a song you want to focus on and also slowing it down if you like. It has various effects for singers or guitarists to use too but I haven't even gotten to those yet so I don't know how they'll make a bass sound. I give it an A+ so far. I give my wife an A+ too!