There's also Karajan on the iPhone as an app.
Not that my opinion is worth that much on teaching things but...
I'm experimenting with simply taking exercises I used to do in Voice classes and playing them in playing them of my bass. It was a speech level singing class. Most of the exercises revolved around playing 1st inversion arpeggios (no 7th) going up chromatically, and then descending after some point. I'm just paying attention to how much spread the hand needs to match the right intonation. 1-3-5-1 is pretty easy to hear and sing in your head. Seems pretty effective so far.
Of course you can vary the exercise and expand on it so that it's more than just a simple arpeggio but it's probably worth nailing that down cold before moving on. If it works for singers, why won't it work for bass players?
Not that my opinion is worth that much on teaching things but...
I'm experimenting with simply taking exercises I used to do in Voice classes and playing them in playing them of my bass. It was a speech level singing class. Most of the exercises revolved around playing 1st inversion arpeggios (no 7th) going up chromatically, and then descending after some point. I'm just paying attention to how much spread the hand needs to match the right intonation. 1-3-5-1 is pretty easy to hear and sing in your head. Seems pretty effective so far.
Of course you can vary the exercise and expand on it so that it's more than just a simple arpeggio but it's probably worth nailing that down cold before moving on. If it works for singers, why won't it work for bass players?