At Coachella on Friday night, I had the thrill of seeing one of my musical heroes, John Paul Jones, play live with Them Crooked Vultures, which also features Josh Homme (Queens of the Stone Age) on guitar and vocals and Dave Grohl (Nirvana, Foo Fighters) on drums. The set had a lot of highlights--including a tremendous jam on "Scumbag Blues"--but my favorite part was seeing Jones switch between instruments, including basses with four and ten (!) strings, a mandolin, and a keyboard.
As well as...this thing. It looked like some sort of slide guitar with an electronic screen. I'd never seen anything like it before, so I did a little digging and found out from a March interview in Bass Player that it's a custom-made axe created by Hugh Manson, who has been Jones' tech for some time and who owns a reknowned guitar shop in England. It's essentially laid out like a lap slide guitar, modified so Jones can sling it over his shoulder and carry it around on stage, and with two extra bass strings at the bottom.
So what about that rectangular screen? According to a forum post on the EMG pickups site, it's a MIDI controller that Jones can use to trigger stage lights. I imagine it could also be used to trigger various effects, similar to the modified Korg Kaoss controller that Manson built into a guitar for Muse's Matt Bellamy.
The million-dollar question: how does it sound? Jones used it to play lots of sliding low notes, so I guess the nearest equivalent would be a fretless bass, only lower and rounder. I thought I also heard slide guitar, although it was a bit hard to distinguish from the overall sound. The entire band sounded fantastic, like a more progressive version of Cream, and all three are absolutely incredible musicians. Check them out if you're into live guitar rock.