Great false tones to me are a seamless low effort transition to the range below where 3 valves normally work down to the pedal. Instruments without good false notes will not allow the air column to vibrate at the desired pitch using the desired valve combination. Example: I own a 3 valve BBb tuba th...

A google image search for "cut away tuba mouthpiece" should provide some ideas on what has been sone before.

The least expensive way to see whats going on inside the mouthpiece may be a clear Kelly lexan mouthpiece and a smartphone camera recording.

The one on the left looks very similar to the Tuba Exchange TE-1915 BB (Miraphone 191 copy) that I used to own.

Some French horns have screw bells. Not sure of the specific dimensions of your saxhorn but would something like that measure up?

The one I tried a few years ago (2018?) played like a piston version of a 186 Miraclone with a more dull sound.

Would work well enough for most amateurs looking for a decent 4/4 piston BBb.

Personally I think a king 2341 or similar would be a better option, but I like pancakes more than chimneys.

For 4p 1r tubas it could potentially be integrated into a heavy weight valve cap and not look too conspicuous.

Just an observation - clearances in the area where the 5th linkage needs to go seem pretty tight.

Position and angle of the valve set relative to the downstream tubing. Also the length of tubing off of the 5th valve.

I think I understand enough to ask some questions: So basically when we :tuba: some of the energy within the instrument :wall: and the rest :slap: :smilie7: and makes sound. Does energy get absorbed by the instrument trying to make it vibrate sympathetically or does that energy go into making more s...

To me, it is still a mystery how a skilled tuba player choose between the different keyed instruments, valve systems, "compensated" and "non compensated", etc. We all start with what is available (typically the instrument is owned by the school or band that we start playing for)...

The one from the left (now on right) is a King - additional photo for scale https://lh3.googleusercontent.com/LSnqVjdzvy9CX_8ZRiKNkGsqQI9hRXw7psyzd3nVAxZw5X7-tVH38ZLOh_tSRVb_U36EYMcPXRAI4VbYm5IR-uR8SHcQXQ9a-2f_Ynk6RZlqYehPn1sNVV8KAp9-1Z8cMCT9ohBfO43mI07YANWdb3bwaj_pCXthcu3Yfx4XrYLJySbU1pcG-hvgBwoRzV...

humBell wrote: ↑Thu Oct 22, 2020 9:30 pmA Holton and a Conn? (I am not so good at id-ing, so i need the practice...)

The one on the right is a 30 inch bell Martin Mammoth (with a Conn neck and bit)

Here's two fun sousaphones for your appreciation!