Altering a backbore...or uhh throat (whoops)

[imperialbari]

bloke’s tech advices are all right. Only in one matter I am somewhat doubtful: the longer the cylindrical part of the throat, the more the mouthpiece determines the intonation and lipping gets harder. Tight slots are fine, if they are placed where you want them, but how often does that happen with tubas?

If I can get my hands on the right tools, I rather let the narrowest point just after the funnel in the bottom of the cup stay untouched. I try to open the opposite funnel from the stem end.

And then I mostly open up the widest end of the backbore. In some cases I only chamfer/undercut the lower edge to avoid turbulences.

Klaus

[imperialbari]

bloke’s suggestion for getting a conical throat takes a craftsmanship not bestowed on me.

There may be a bit of cheating in my modifications insofar that I used some pro-level reamers from a friend’s machine shop for working on the area of the backbore closest to the throat. And I secured the reamers by means of a vice like bloke told, even if this happened before I knew much about bloke.

My own hand tools are three cheaper and slightly modified reamers intended for cleaning up smoking pipes plus a conical reamer from a hardware store.

Klaus

[Roger Lewis]

Okay. I would recommend great caution on modifications at this point. I would also have some questions for the OP.

If you just blow air through the mouthpiece, does it back up on you? Before altering the mouthpiece I would examine the potential for operator "improvement". I often find that the backpressure many players expeirence is built in at the embouchure rather than having anything to do with the equipment. I have not found a mouthpiece the would back up when I just blow air through it (unless it's a trumpet mouthpiece). Before doing any thing, try "The Spit Valve Drill", posted sometime earlier by me first, then look at your options from there.

Now, as to drilling the mouthpiece, several things will happen. The great "secret" behind mouthpiece design is what is called the "straight pipe". At the throat of the mouthpiece is a drilled hole of a specific length, before the taper begins to expand to the stem of the mouthpiece. The longer this 'straight pipe" is, the better the slotting of the notes will be, but the sound will tend to go a bit brittle. The shorter it is, the better the sound is but the slotting goes away.

Examples:
PT88 short straight pipe = big dark sound with a tendancy to slot well but not as tightly as some people would like;
Marty Erickson ME5: longer straight pipe = a bit brighter with better slotting, will articulate more cleanly but some may find the sound a little bright for their tastes.

As you drill a mouthpiece this straight pipe becomes longer, so if you go too far it may change the overall effect rather drastically. Just remember - it's really hard to put it back the way it was.

Just my $0.02.
Roger

[tubatom91]

I think that I am going to try this experiment tonight. I have done a bit more research and found that the Yamaha 67C4 throat is 8.1mm (.318") which is identical to my PT-88's that I like soo much. Which means of course this wont be an experiment to "even" the two mouthpieces out. I just think these two mouthpieces will make excellent examples of what a "larger than stock" throat can do for the sounds that come out of the bell or just how it feels to the player. I tend to enjoy more or less shocking my band directors with some of my "experiments" or shenanigans. I even shocked them with my giant mute today. But this isn't really about that, it's just an added benefit. I think I'm just a tinker-er by nature. But anyways I think that I'll open this mouthpiece up to where I think I am satisfied and then STOP. I certainly don't want to open this mouthpiece up to where it's un-playable or to where I deem it un-playable . Maybe we will all learn something from this experiment. I know that I've learned quite a bit from Roger when I came and bought my horn last year and that was before I even played my new horn. And I certainly thank all of the posters on this particular thread (Bloke, imperialbari, Todd) for teaching me quite a bit about this subject. I may not get the results till tomorrow but I'll plug it into my Besson 3 valve tonight (My primary horn is at school).

[tubatom91]

I just finished. This was pretty cool, the only trouble I had was after I was tunring the mouthpiece for awhile and my arm started getting tired . The results are inconclusive, I'd love for a person that knows alot more about this stuff to try this out. I bored it out a bit larger than originally anticipated, I think I went further because the 67C4 throat is already bigger then the original C4/TU23, which I just learned today. Both the stock 67C4 and the new mod. 67C4 sound great on my Besson and I am learning to love this old tank of a horn . The low register is great!(talking of mouthpiece alterations). I like the way this turned out, I am sure I will learn a little more once I plug it into my CC, I'm not really used to this Besson. Like I said before, I am sure that a pro player could give you guys a little more insight as to what kind of monster I've created.

I will call this a success. And this was easier than I though it was going to be, thanks to you guys! If you are ever in Aurora/Chicagoland and you want to try out this mouthpiece let me know

[Matt G]

I thought at one point Marc. made a piece that was a C4 replicate with a bigger throat, similar to the desires of the OP. Maybe a "Solo" model of someone of high repute?

[tubatom91]

I used this piece in Wind Symphony today, playing Elgar's Enigma Variations. This mouthpiece is great at high volumes. I had no problem pushing the volume up without worrying about loseing the tone. I was surprised that while this did help the low register, the high register is still there and sounds just as good as it did pre-modifacation. I can't really imagine doing this test to anything other than P.O.S. mouthpieces but I do think the whole reverse taper theory has a lot of merit. IMO this experiment was a success, I might of course be tricking myself into thinking I did somthing great with this modifacation but I think I like it. My band director looked at me funny when I showed him the mouthpiece, he thought I was using a stock 67C4 and was very confused considering I almost exclusivley use my PT-88/PT-88+ in Band/Orchestra. It was more of a "why are you playing a Yamaha....Oh I get it now." I think I am interested in some other mouthpiece now...

(How much is one of those "bloke-pieces" again?)

[iiipopes]

I agree. I don't know why a particular throat design works, either. For example, I am more secure on the high range of my Besson with its really, really deep Wick 1 with a large throat (8.42mm and open backbore) than I am on any shallower mouthpiece or smaller throat mouthpiece on this on any other horn I have played.

Probably for the same reason a jazz or commercial lead trumpet player tends to use a mouthpiece with a larger throat: can utilize more air. What I mean by that is a larger velocity of air, not necessarily volume, with Bernoulli's principle: greater velocity, lower pressure, facilitates higher pitch.

[MaryAnn]

Now, as to drilling the mouthpiece, several things will happen. The great "secret" behind mouthpiece design is what is called the "straight pipe". At the throat of the mouthpiece is a drilled hole of a specific length, before the taper begins to expand to the stem of the mouthpiece. The longer this 'straight pipe" is, the better the slotting of the notes will be, but the sound will tend to go a bit brittle. The shorter it is, the better the sound is but the slotting goes away.

Roger

So can you relate this to bells? I have two bells for my horn; one is the stock bell that plays and sounds like crap, and the Lawson bell that plays and sounds great. In hearing other people playtest this bell, it is clear that my impression that it causes the notes to slot better is not fantasy; one fellow, a much better player than I am, played some difficult concerto excerpt on both bells, more than once. With the Lawson bell, he hit a LOT more notes than he did with his (same brand as mine) stock bell. I figure it has to do with the tapers, and know that Walter Lawson was some kind of mathematical genius with that kind of thing. Lawson leadpipes have internal tapers, their mouthpiece cups also make slotting easier, and of course their bells have the above-described effect. But since a bell doesn't have a "straight pipe" it must be the tapers. Right? Some part of it is the metal (more massive than the stock bell) but that doesn't seem to be the factor that would influence slotting.

Now when I get home tonight, I'm going to look at both bells and see if there is some difference that I can discern, of a "more straight" or "less straight" section of the bell before it begins to really flare out. They both have the same ID at the ring.
MA

[tubatom91]

To give you an accurate measurement of what I did to this piece, it went from around 8.1mm (.319in) to 8.7ish(mm) or .344in. I imagine that it is a tiny bit larger than that because of the sanding and other factors. I also reamed the backbore open a little bit. I am very pleased with this mouthpiece. I might customize this piece more later on down the road (Narrow down the rim, and maybe smooth out the inside of the shank a bit better) Maybe I'll scrape "TubaTom" into the side and re-plate it just for kicks.

[Matt G]

If you put an approximate "Hellebergish" size throat (again, roughly 5/16" - 21/64") on your Mirafone C4, you'll have something approximating the very old Mirafone Rose "Solo" model.

That's the one! I thought it was a Marc. piece, but it was a Mirafone Rose "Solo". That was a pretty solid F tuba piece, IIRC. Does Mirafone offer anything similar in the TU** line?

Also, in regards to the 188CC: Try a Bach 7. They are relatively cheap and are a pretty good match for the 188, IMO.

[windshieldbug]

Mouthpiece TU27, Tuba Rose Solo, cup shallow, cup depth 37,9 mm (1,492 inch), bore 8,2 mm (0,323 inch), cup diameter 33,0 mm (1,299 inch)

[windshieldbug]

Works for me, too!

[kingconn]

I've opened mouthpieces up to 3/8 before with good results but much more than that is pushing it.
mike

[Tubaryan12]

I altered my first mouthpiece yesterday. It took me over 30 years of playing to finally get brave enough to do it. So far I'm very pleased with the results.

[tubamirum]

Since you have a mouthpiece to experiment with keep records of the results of each drill bit. As the bits get bigger the venturi becomes longer and straight, there will be a point that the mouthpiece won't be much good because the venturi is not as efficient as the original. Have fun and use the nouthpiece a day or two between drilling.

[Tubaryan12]

Since you have a mouthpiece to experiment with keep records of the results of each drill bit. As the bits get bigger the venturi becomes longer and straight, there will be a point that the mouthpiece won't be much good because the venturi is not as efficient as the original. Have fun and use the nouthpiece a day or two between drilling.

There will only be one drilling on this mouthpiece. I had a pretty good idea of what I wanted. I wanted the throat to be slightly smaller (8.2-8.3mm) than the 2 Mike Finns that I play (8.43mm) and I got just what I wanted. The throat of the Melton started out about a hair under 8.0mm. The result I wanted was easier low range. Low range on the Melton 67C was more work...almost to the point of having to think about it. As for the Mike Finn, the low range is almost too easy, but it makes playing softer more difficult. The mouthpiece I created from a Melton 67C is almost like a Bach 22 with more contour (for lack of a better word) to the throat. For me, it worked perfectly. Now, if there were only an easy way to make the throat of a mouthpiece smaller......

[tubamirum]

You can make the throat smaller by not cleaning it.