The insert for JABB describes the tuba as a "Bb Tuba". I've consulted several orchestration books that list a Bb tuba as a "tenor tuba" and one that calls it a "tenor tuba (euphonium)". The JABB tuba's range extends to the C on the treble staff and goes below the generally stated ranges for the Euphonium (2 Eb's or Bb's below middle C). My best guess is that the instrument is a Euphonium and the JABB range includes all the pedal tones. What I am most concerned about is, is this a wide bore instrument, like a tuba, or a narrower trombone-like bore (what some books refer to as a baritone horn)? My other concern is that all the sounds in this patch came from a single instrument (not using a smaller tuba for the upper notes and a larger one for the lower). I want to be sure that what I write can be played live by one performer without having to switch instruments.
The Garritan Personal Orchestra also includes several tuba patches but does not describe them in the manual. In fact, there is also a "contratuba" which is not listed at all. I am trying to match them with what I see in my orchestration books (Bb, F, BBb, and CC). This is important, because, while I can deduce the comfortable ranges from looking at the keyboard mapping in Kontakt, the books tell me which fingerings are difficult and other performance considerations which I am trying to take into account when orchestrating. Again, this is all geared toward an eventual live performance. I don't mind if the parts are a little difficult at times, if I am trying to get accross an interesting musical idea. But there's a difference between difficult and impossible and I'm trying to respect those limitations.