You can learn all the Modal scales in a single box on your bass as long as you have 5 strings. If using a 4 strings, you will need to makes shifts starting at the Mixolydian Mode. Remember the following formula as for which finger to use first, and on which string, while first learning the 7 modes: C Major: Ionian-start with finger 2 on C on the E string/ Dorian- finger 4 on D on the E string/ Phrygian- 1 on E on A string/ Lydian- 2 on F on A string/ Mixolydian- shift up to finger 2 on note G on the A string/ Aeolian- shift up to finger 1 to A on the A string/ Locrian- shift up to finger 1 to B on the A string.

Do this in all keys!