Promise to not make a habit of it, but this week’s Friday Downstream link is the same as last Friday’s: the BBC’s Mixing It radio show, at bbc.co.uk/radio3/mixingit. Same link, but new show, as each Friday brings a brand new broadcast. This one features — in addition to fine commercial recordings by Sion Orgon (real-world sounds warped until they sound like avant-garde chamber music), “underground hip-hop” mainstay El-P jamming with jazz musicians (among them Daniel Carter, William Parker and Matthew Shipp) and Mira Calix (mixing live insects and orchestra) — live studio performances by, and conversation with, Californian tuba player Tom Heasley, whose deeply reverberant solo works are often reminiscent of whale song. Heasley talks with the Mixing It hosts about his early improvisation experiences on tuba with one of jazz bassist Charlie Haden’s large-scale ensembles circa 1984, the influence of Robert Fripp (whose 1970s “Frippertronics” work make him think, “I could sorta see doing something like this with a tuba”), his prized loop sampler (“[It] records 14 seconds of music, and then you can overdub over that, and it just constantly mixes together and it becomes other things”) and the differences between a tuba and a didjeridu, which he also plays. More on Heasley at, naturally, tomheasley.com.