Bridge angle across the strings (not asking about bridge lean)

[Jack Clark]

Why is it that the bridge on a double bass is positioned 90-degrees to the strings, while the saddle on a bass guitar is angled so that the scale length of the treble strings is shorter than the scale length of the bass strings?

I understand that with a bass guitar it has to do with the variance in the thickness (and perhaps makeup) of the strings, which causes them to distort the tone more or less when pressed to the fingerboard, but why wouldn't that principle apply to a double bass also?

[JtheJazzMan]

I think I know what youre getting at. Double bass doesnt have frets, so you intonate by ear. Theres no need to fudge the string lengths.

[Andrew McGregor]

It's called 'end correction', and you need it on a fretted instrument to make every fret line up with a correctly intonated note (in so far as that is possible). On a fretless instrument, that's up to the player, and so there's no need.

Also, with DB, the correction is far smaller anyway.