I used to play mostly trombone in trad jazz bands. I got turned onto the cornet, and there was a need for someone in our area to play the cornet, so I got it "up to speed". For a little while (short to be honest) I tried to double on trombone and cornet, but found the switch of mouthpieces and embouchures really uncomfortable, disorienting and well, made me worse on both when I switched from tune to tune.
So I stopped playing much trombone, since the cornet is smaller anyway and easier to travel with! Recently I joined a NOLA style second line band and there were 5 trumpets but no sousaphone players. The leader had a sousaphone laying around and asked if I'd be interested in playing. I gave it a go and it turns out I love it! With the 2nd line band I just play sousaphone now.
So this is the real question: I took the sousaphone AND my cornet to a swing jam the other day, thinking that I'd switch back and forth. I guess I had forgotten the issues with the trombone doubling. I hadn't tried to switch back and forth before this jam, and I found that not only was it disorienting and uncomfortable, it was darn near impossible for me to lock in my cornet embouchure after playing sousaphone for a tune. I just couldn't do it, and it got worse every time I tried. And it was very psychologically disorienting and uncomfortable. It felt like Alice in Wonderland or something. The cornet felt so awful and my lips felt rubbery and uncontrollable.
This is a long-winded way of asking WTF? I love both of these instruments (and trombone too), and I would love to be able to switch around on them, but maybe that's just a pipe dream. I don't see it done very much and maybe this is why, but it seems like at best I'll have to choose one per set, or maybe one per day. The technique and calibration are just too different for the accuracy required.
I do remember when I tried with trombone/cornet, that my embouchure on the trombone started fluttering uncontrollably on lower notes, and it felt that the actual muscle development caused by the cornet embouchure was interfering?
Anyway, does anyone have experience with this, and have tips, suggestions for me? Or confirmations that this is a pipe dream, or maybe just not meant to be, or not meant to be for me?