Back in the mid 70s, Howard Johnson organized an all tuba band, six or seven of them, I think, called Gravity; maybe it's still extant, I don't know. I remember Braxton running into Johnson at Environ, enthusiastic about writing for the ensemble; also don't know if that ever happened. I guess there have been all tuba projects in the interim but I doubt they've been as focused and fascinating as this trio.
Two C-tubas and an F-tuba, the latter microtonal, though all three in tandem certainly depart from pitch standards. One track, some 32 minutes long, one linear idea. Linear, that is, stepping back a few paces, the way a dense rope might look linear. Within the strands, however, is an amazing depth of twining tones, long-held, resonating, forming fluctuating pulses that buffet the eardrums in delicious fashion. For the first half, well, there's more variation than in a set of Sachiko sines but it's arguably in the same ballpark, one long stretch of tubaic taffy. They then descend, spelunk into the depths of the horn, the dark booms augmented by soft breath sprays like decompressing oxygen tanks. There's water down there, cold. They emerge slightly, blink at the light and continue on, down an adjacent path, before encountering an obstacle, hesitating, sending out gentle feelers, stopping.
A fine recording, give a listen.