Sure...There are passages in both (with Pomp #1 - the soft, separated bass line in the part recognized by all, if nothing else) which would be tons of fun to play on a huge contrabass tuba, yet there are plenty of passages whereas both of these compositions holler "bass tuba, bloke !!!"
The lowest pitch found is the "cellar" E-flat, but a whole bunch of both live in the staff (as well as around the top of the staff).
Not that I'm any sort of "period instrument" person (everyone here knows that I'm perfectly happy playing my extra-large-belled compensating euphonium with an Elliott contrabass trombone mouthpiece - when playing ...ok: "some-to-most"...older French-written orchestral music)...but you won't see me with an ophicleide or serpent when playing Mendelssohn, or anything like that....but (as the E-flat tubas during Elgar's days were the 15-inch-belled type, I'm probably going to play BOTH of these works (as much fun as it would be to play the lower-tessitura portions of these pieces on the BIG tuba) on my F tuba.
The temptation (hee-hee...yes?) is always to use the largest tuba we can possibly get away with using, but - for those who've also played these before - do some of you agree that these are (when getting real) both bass tuba parts?
What else is on the concert...?? Prokofiev piano 3...no tuba, and even were it that I was offered the bass 'bone part, (well...) that part sucks.
, arranged by Arturo Toscanini during WWII). 
). 
