TIP OF THE MONTH: The best way to start learning and applying music theory to the neck of your bass is to realize that every scale you know has its own set of modes; that is, start on any note with/in a scale you know, and end an octave higher. You likely already know that if you start on the 2nd degree of a major scale and play up to the 9th, you get a Dorian mode (the cool thing is that your Dorian scale has a life of its own separate from the major scale where you found it). SO... Use that same technique with every scale you know. Instantly, you have a truck load of new scales. Now learn them in every key. Don't worry about what they are called in a theory book. Just learn them (for now). Perhaps start with Major and Minor pentatonic. Next step, find all the "modes" in a Major scale.