I tended to think of the word intonation as something to do with the pitch accuracy of an instrument, to borrow from official definitions. But one of my teachers said something that blew my mind - intonation is muscle memory, nothing more, nothing less. When we are playing on the double bass, our intonation (or lack of, in my case), comes from our muscle memory... and lack thereof. So I've started to add more drills in the parts of the scales I'm working on when shifting is involved.
Namely, the following shifts need more work:
- Shift to C (and also E) on the G string (C, F, G, Eb major scales)
- Shift to Eb on the D string (when playing an Eb major arpeggio)
Rather than play the scales through, I'll opt to zoom in on just the area before and after. For example, if playing the F scale, I'll start on the open G string (which serves as an anchor), and then A, Bb, shift to C, D, and play open D to reference check. If (and most likely) my intonation is off, I'll take a mental note if it's flat or sharp, and then repeat with a mental adjustment, e.g. I need to shift less.