As many of you who have followed the B.A.R.T. saga may know, the original leadpipe has a huge opening, as big or possibly even bigger than some of the older Alexander Kaisers. I took a sousaphone bit (Conn?) and cut it off right before the bend. It fit inside the original receiver just a little loosely, so for testing purposes I used some of that red Selmer tuning slide grease to make it fit airtight. I like what it did for the horn, so I cleaned everything up and soldered it permanently. A standard shank mouthpiece fits perfectly, and the horn is now much more ergonomic since the collar of the bit adds about another 1/4" to the leadpipe and the mouthpiece protrudes an appropriate length. I can now take a 100% full breath when playing
Having the mouthpiece out a little further has tightened up the horn and improved the response slightly. I have found no negative playing characteristics yet, except that the overall tuning has been lowered enough to warrant getting out the hacksaw and torch again to make pitch at one of the ensembles I play with that tunes a little on the high side.
I originally had Matt W. create an adapter for it, but a standard shank mouthpiece still went in almost too far, even with the adapter. This may be because the adapter was then modified by him to accept a sousaphone bit to help with the leadpipe length and angle. I found that the horn did not play nearly as well with the bit and have not used the bit regularly, hence its cannibalization.
