But tempered pitch, used to create 12 equal 1/2 tones, is itself a compromise to allow all scales to be played on a keyboard. Even on a well-tuned concert grand piano I can hear the compromises.
I repeat, when we go on stage or to audition, we have to be (a) able to tune our bass as best we can to a given A, (b) adjust our pitch relative to to the other instruments we are playing with, and (c) devote our most attention to the job in hand. We have to be able to pre-hear notes before we play them if time permits so that if we are slightly out we can adjust, either instantly or during the next few notes. All this requires both confidence and flexibilty.
I am not saying there isn't a place for a good tuner or drone occasionally but IMO it should not be constantly on the music stand beside what you are practicing, like Jimminy Cricket and Pinnochio. How do you build confidence in the structure of a scale? If you constantly use a drone, say open D string for D major, what happens when you turn off the drone that you have been focusing on? Are you, the student, left feeling more confident of ANY scale or chord structure.
What I am suggesting is more like the time-honoured European system of Solfege, but pausing between each tetrachord, in order for students (and professionals?) to gain confidence in structures that apply to any starting note. I liken it to playing musical darts,aiming for a series of bullseyes that are coming towards you and are strong in your mind. Perhaps some of our European colleagues could share their thoughts about Solfege?
I disagree with the claim that using harmonics to tune the bass by ear risks putting you so far out of tune across the strings - unless you are insensitive, or a beginning student with no previous musical experience, or you are on stage beside the tuba player warming up. The little watch-sized clip on tuners are not great then, but better than nothing.
All this makes me sound like a Luddite but I am not.
DP
ps Some advice I was once given when playing with piano accompaniment. Try tuning your open strings to the same name notes in the middle of the piano keyboard and see if playing in tune with it is easier. This will certainly put your harmonics askew, chicagodoubler!!