With a smaller tuba it is much easier to excite the harmonics of the instrument, thus giving it a little more "brilliance" or "sizzle." IMHO, that more excited sound supports the upper instruments and gives the chords a certain flare, especially if the group actually listens harmonically and "locks their harmonics." I don't believe an instrument that produces a sound with so much more fundamental, and little upper harmonics in its recipe, functions in the same manner. This is very hard to describe.
The size of the tuba also needs to connect to the depth of sound of the other brass players.
PaulMaybery wrote: Players such as the older Chicago Symphony Quintet sounded fine with Jacobs on the 6/4.
New York Phil Quintet with Bell on a King 4/4 and Torchy Jones with Abe on a King 4/4 also worked. Historically with the NY Brass Quintet, which is probably the 1st quintet to appear regularly from circa 1950, Harvey used a very small Conn CC. When Toby replaced him, he used a 184. Canadians with Chuck used small equipment. In the P Jones Brass Ensemble, John Fletcher used a Besson Eb. (But that was not really considered that small of an instrument being that it was the standard orchestral tuba in the UK.) I believe Sam was using a 4/4 CC with the Empire, likely the M-W Wm. Bell Model. They eventually wound up with the Eb.
These groups all had very different sounds and styles of playing. Some seemed very light and bright and others who were also affiliate with orchestras, much heavier sounding. What intrigues me is the dynamic range that the group, and the tubaist, is able to produce. Unfortunately I've heard too many relatively good groups that stay in that "mezzo forte to forte" range, and never really whisper or shout. A good and well suited instrument can help in this area tremendously.
Going back to my opening statement and making a further comment: As far as 'Brilliance" and "Sizzle" it is indeed very possible to make that happen on a 6/4, it will simply be proportionally larger than say a 3/4. If the trumpets, horn and trombone all have huge sounds, then perhaps you've got a match.
Interesting side bar: For a time, I thought Fletcher used his 6/4 Holton CC on the PJBE recording of the Malcom Arnold. You may recall the cover photo of the group standing in front of the British Museum and the Holton is sitting promenently on its bell. Back in '79 I lived in the UK and would meet with John regularly. Regarding that photo, John mentioned that he got a call to show up early in the morning for the photo shoot and to bring the largest (BAT) tuba he had, simply for the visual effect. Until, then I wondered how he made it sound so focused and expressive. Then I learned that he played the PJBE concerts and recordings on the Eb.
Although the recording I have of the Chicago Symphony Brass quintet is very recognizable for the bounce and brilliance of the tuba playing, I believe Mr. Jacobs was actually using an American E-flat tuba rather than his big York CC (not that he wouldn't have sounded great on that, too).
(not an April Fool's joke) than my will-never-sell-it 4+2-rotor Symphonie model (same config).
