Slap a double bass? You've got to be kidding me. Sure, Stanley Clarke's done it, but he's Stanley Clarke. And his slapping was more like very deep percussive thumping.
Hi Jubs, for Bluegrass(where slap kinda started) to Psycho-billy stuff just look for a plywood upright, you'll also get the best results with higher action and nylon strings on the D & G. My upright is a '60s Engelhardt(they bought out Kay) 3/4 size and it sounds great.It's not set quite high enough for slapping but it sounds awesome for jazz/singer-songwriter stuff and isn't that bad to bow. That brings me to my next comment.... LEARN HOW TO BOW THE INSTRUMENT if you really are gonna get one. Be sure to take lessons and really go at it ,to begin with, with a classical angle. The best way to physically learn to play the upright is to start by bowing and learning your Simandl stuff!! you can play pizz. (fingers) all you want outside of your lessons but a good classical teacher would be an almost 'must have' to start off with....
sorry for the rant
...the ungentle art.A rockabilly guy I know shocked the bejesus out of his classical teacher when the teacher showed up to check him out at a gig.Apparently jumping on the side of the bass while slapping the **** out of it is frowned on in classical circles....go figure....He once had an upright "explode" on him in the middle of a gig.The local repair guru was not impressed with his "technique"and gave him a bit of a lecture. I am amazed by the guy's right hand...mine would be hamburger after a few minutes of that abuse.
A plywood Kay or Englehardt is probably your best bet. Many poeple are leery of the cheaper Chinese and Czech stuff....the plywood basses will take more abuse and require much less maintenance.....Good luck
However, I gotta say: if this is gonna be your first upright, really, really rent one first. I bought an Engelhardt a year ago, but I'm likely gonna sell it soon, mostly because it's just so damn BIG. It's physically painful to play the lower register. Not to mention the transportation problems it brings up, and the absolutely insane cost of ownership: an initial setup can cost around $500. I'd hate to imagine the cost of a repair, considering that these things are relatively fragile.
I don't mean to discourage you from tryin' double bass, because it really is the coolest sounding thing in the world, but make sure you know what you're gettin' into.
uprights are an adventure to amplify.....depending on the volume you will need.They are miserable to lug around, they require maintenance, and it takes time to build up the hand strength and stamina neccessary to play.Intonation is another issue.Leo did us all an incredible favour when he introduced the Pbass.Having said that....nothing sounds or feels like an upright.They are not for everybody.If you are into rockabilly you will have to get one....there is nothing like watching a great slap rockabilly player practice the craft....