Double Bass Intonation Problems on one string of an upright bass

Ok, looking at the nut I'm inclined to agree about the setup being by a guitar or slab luthier... probably best of intentions but if the person had a background in basses or violin-family instruments it would look a lot less chunky (wood would have been removed so that the slots aren't so deep). Ideally you could just barely slide a business card between the fingerboard and strings at the nut and feel some slight resistance.

Is this a month-to-month rental or was there some type of longer term lease? Setup is everything on DB, and a far cry from truss rods and saddle screws. Must be frustrating to finally get your hands on a bass and realize it's close to unplayable, but you've come to the right place to learn what a good setup is. Gotta start somewhere! I think being a TB/DB member and spending time in setup/repair should be a prerequisite for anyone setting up basses... :D You could even tell the rental shop about resource, just sayin..

What area of the world do you live in, @Colin Kyger ? And who made the bass, is there a label inside? If it's of decent quality it may be worth getting that particular instrument righted, but in case you missed the newbie links at the top of the forums, there's a whole category of instruments that are (not so) affectionately referred to as bass-shaped-objects. Occasionally unidentified flying bass-shaped-objects. It's a blurry line, as some really crappily built basses actually sound good, but if it's one of these and you're serious about learning the instrument, it will likely be worth finding something better.

$.02
 
here's what you need - just bolt this on:
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