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Lower brass and middle brass are easily my favorite instruments.
Flute is also pretty good in it's lower range.
Technically I can play tuba 'cause it has the same fingerings as tenor horn (I play both french and tenor) so if they were desparate I could temporarily do any brass part, but if I do it too regularly it'd fuck up my horn playing/embrasure and it'd also tire me v. quickly 'cause of how much air you need to push through it. I've had to play baritone and euphonium to fill in gaps at my brass band a few times.
I'm primarily a Euphophonist/Bass Trombonist, but all low brass is fun. Tuba is pretty easy for me because I'm fairly used to the loose embouchure (and the fingering is the same). Tenor horn is kinda similar to Eupho/Tuba so I can get by on that, and then Eupho is the same as Trumpet (just transposed and pretty damn high), but my French Horn playing is all over the place q.q
Also Flute damn, the only Woodwinds I can play are Clarinet/Bari Sax (albeit terribly ahaha).
I can't play flute but I love the sound you can get out of it if it is played well. Woodwind is a blur for me 'cause if you play brass you can't play woodwind and vice-versa.
When I play tenor horn I have to use an adaptor that lets me use my french horn mouth piece in it so that I can use the same embrasure when playing it. The sound that I can get from the instruments is fucking incredible which is why I love the french horn so much, and playing french has directly improved my tenor technique due to this ability to use the same mouthpiece for it (and trumpet too although idk what the sound is 'cause I've put the mouthpiece into one but not actually played it).
Probably the coolest sound u can get from a tenor horn is when you play it with a trumpet mouthpiece 'cause it sounds somewhere in the middle of trumpet and flugel horn.
Speaking of flugel, the sound that you can get from it is utterly beautiful.