Here goes 1) Diads. How are you musically "correct" with diads? For instance in C. I know I could play C and E. But would it still be part of C and harmonize if I played D and F? Do I have to space the notes an interval apart? Are diads only playable if they're roots & 3rds, 3rds & 5ths, etc? 2) Playing by ear. I did a search on TB and came up with this thread: http://www.talkbass.com/forum/showthread.php?threadid=20754&highlight=learning+by+ear This does help a lot, but several times in other threads, singing or humming along to the song was mentioned. My question here is, how can I go about learning to sing on-note? When I sing, I can't keep a tune whatsoever. One of my friends suggested playing a note an octave up on my bass and trying to match my voice to it. This doesn't seem to work, as I recorded myself and I sound nowhere close to the notes I'm playing. If I did this a lot, would it help me? 3) Keys. What exactly is a key? If you're in the key of C major, does that just mean you don't play any notes other than C D E F G A B c? If that's true, then would switching to C minor in the middle of a song be musically correct? If my first question under number 3 is yes, then can a song consist of two keys, such as C maj and D maj? Do the keys fit together in any way? 4) Finally, I bought a cord today that consists of one end for the guitar and one end for the amp. Why is the cord made so that I can only plug it into one or the other? what would happen if I plugged the guitar end into the amp and vice versa?