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the elephant wrote:So I have often read that the various Kellys had to be mildly altered to work so well in plastic. I have heard repeatedly on this BBS over the years that this was done in the throat or backbore.

Does anyone actually have FIRST HAND information on this? Not hearsay, not rumor, but actual, from the horse's mouth, uttered by the designer himself information?

Right off the website:

First, Trumpet:
"The cup sizes are patterned after the Bach® series, sampled by our professional staff and are adjusted to produce our final, comfortable, easy-blowing mouthpieces. Our standard trumpet mouthpieces all have a larger throat diameter than their Bach® counterparts."

And, Tuba:
"All cup sizes are sampled by our professional staff and are adjusted to produce our final, comfortable, easy-blowing mouthpieces."

Compared to my "real" Bach 18, my Kelly 18 cup i.d. is 1/100 larger. The cup is somewhat deeper. The throat is the slightest bit narrower. I have a blue one and a burgundy one. The burgundy one has better all-round performance. The blue one feels like it "backs up" occasionally, but works better on smaller bore instruments. I don't know if this is attributable to "normal" manufacturing tolerance in the bottom of the cup transitioning to the throat, but there you have it.

I A/B tested my burgundy Kelly 18 when I got it with a couple of band directors with decades of experience. They could not tell the difference from the podium or across the room.

On all Kelly mouthpieces that I play, I wrap a single layer of golfer's lead tape around the throat to stabilize the mouthpiece at dynamic extremes.

the elephant wrote: Further, or maybe separately, I like my Kelly 18. This is a big admission for me as I have always disliked the Bach 18 as well as all its various clones. Yet my Kelly works wonderfully on my 345 in the difficult low register, allowing stuff to just pop out like on a horn that has had its low range dialed in really well, like a Thor.

However, it is plastic, and for me I feel it lacks the power of a metal mouthpiece. My colleagues hear less of me in the mix when I use it. But they, too, like it (when they are not making fun of my plastic toy mouthpiece, that it). This perception might have to do with me or might be an inborn bias. I have always felt this way about plastic rims or cups. My original one was a white delrin screw rim I had made for me in 1984. Then I had John Stork make me a screw rim from two pieces that I liked, casting a copy of the rim in acrylic for cold weather. Then Doug Elliott made me a polycarbonate rim for one of my R cup pieces of his. I have a delrin cup/rim DEG outdoor mouthpiece, too.

ALL of these have the same loss of power, with the more plastic involved the greater the loss. Whether this is a perceptual bias or not, I am not the only one who senses this.

Agreed. I had a $300 mouthpiece and a Kellyberg and thought I was hearing very little difference. I asked the trombone section to listen to both mouthpieces in the hall, a $30 mouthpiece vs. a $300 mouthpiece. They were all chagrined to admit that there was virtually no difference... until the low register. There was a noticeable drop off in the low register in excerpts like the Ride and Prokofiev 5th.

I thought it was a fine substitute mouthpiece for many occasions.

Stryk wrote:Perhaps the Kellys were modeled after that version?

Don't know, but that would be the norm, inasmuch as Blessing and Faxx 18s are supposed to be modeled after a Mt Vernon version. Maybe someone who has one of these two and a Kelly 18 could comment on similarities.

My Kellyberg's cup profile feels a little eccentric to me, in a way that doesn't seem intentional. If it isn't an illusion, it would be evidence that it's hard to get super precise dimensions out of a molded polycarbonate item the size of a tuba mouthpiece.

Gonna weigh in on the side of the Kelly 18 vs the Bach 18. I just came into possession of a Conn Helleburg and might get a Kellyberg for another comparo. For me, the driving force with the Kelly was the fact that I kept dropping the mouthpiece out of the sousaphone... I like the sound on the sousaphone but not as much on the VMI.

I don't modify them, but the Kellyberg is my go-to MP. Sounds great on a B&S BBb, and works on an F tuba, although the Yamaha 67C4 is actually a little better on the F.

Wade, did you ever try placing some weight around the throat of the Kelly 18?

Klaus

bearphonium wrote:I like the sound on the sousaphone but not as much on the VMI.

Likewise. My primary use of my Kelly is for outdoor concerts where I use the recording bell on my 186.

Yes, I want to emphasize again, like imperialbari stated, to wrap a layer of lead golfer's tape around the throat to stabilize dynamic extremes.

Is it possible that the differences between plastic Kellybergs from piece to piece are just products of the plasic warping during shipment, or of having different densities in different spots throughout the mouthpiece? And on the stainless side, newly cut SS forms a sharp edge, so it's only natural that it would have a less forgiving rim.

hrender wrote:As mentioned, the specs are different. Kelly 18 has a wider cup (32.76 vs. 32.1)

Bach's numbers are notably smaller than mouthpieces that appear to be the same size, to the extent that I wouldn't be surprised if an actual example measured 32.76 in someone else's calipers. I don't have an 18 nor any clones to verify this, and don't know how consistent they are, just have read this about the 18 specifically (and see it in a 1¼G trombone mouthpiece.) So that's something (in my opinion anyway) to bear in mind while trying to sort out the dimensional innovations. If you can get the story from the Kelly 18's designer, as the original question was posed, that's great, but comparing published dimensions is probably not a good substitute.

Hey, want to talk about Home Depot?

Why don't you ask your teacher

or better yet:

Contact Kelly himself - I'm guessing they still have a phone. I've also emailed them in the past and they have promptly replied to my specific questions.

This way you don't have to ask the tnfj and can stop being crabby Lucy.

Though to be fair, it can be expensive to acquire every mouthpiece you're curious about. The man of the hour would be a reliable observer who actually had a Kelly 18 in both stainless and polycarbonate. We're just bumping the thread until he comes along.

"the elephant" on rampage - meanwhile - back at the farm the TNFJ jams furiously looking for answer.

Donn wrote:

hrender wrote:As mentioned, the specs are different. Kelly 18 has a wider cup (32.76 vs. 32.1)

Bach's numbers are notably smaller than mouthpieces that appear to be the same size, to the extent that I wouldn't be surprised if an actual example measured 32.76 in someone else's calipers.

Bach, both historically and currently, are notorious for not keeping their bits sharp and calibrated. I've had almost a dozen Bach 18's over the years, either borrowed, bought, swapped, etc. No two were exactly alike. No two ever are, or ever will be. I've had them with 1.26 cups with the wide sloped Mt. Vernon "classic" shape, both to cup and rim, and I've had them as large as 1.28 with a rim that looked like a trumpet 3C rim.

Yes, that's how I measured the differences between the throats of the Kelly 18's and the Bach 18's: I took a pencil and started wrapping layers of masking tape around them until they would not fit through the Kelly 18's. At that point, they would still fit through the Bach 18's.

There is more consistency of my two Kelly 18's than in all the Bach mouthpieces I've ever blown. And they may not be prettier, but they do sound better out front with the golfer's lead tape around the throat.

Elephant,

I can't specifically answer your original question regarding the difference between the Kelly 18 and the Bach version.However, I do think that there are custom mpc makers who could easily take a mold of your Kelly 18 and produce a nearly identical one in stainless steel or brass/silver plate. You'd just have to query the usual suspects to see who does this kind of thing. I assume you are interested in a metal mpc with the dimensions of your Kelly and not just in an academic discussion of the differences.

Good luck! Hope you'll post about the mpc if you do finally get a metal 18 that matches your Kelly.

royjohn wrote:I do think that there are custom mpc makers who could easily take a mold of your Kelly 18 and produce a nearly identical one in stainless steel or brass/silver plate.

Jim @ Kanstul did exactly that for me. Their "18" has a deeper cup than the Bach, but has a slightly smaller throat, .328, instead of the Bach "special" for an 18 of .348. It is also just slightly shallower than a Kelly 18. I had him make one in my preferred 1.28 cup diameter rather than the stock 1.26. I use it with my recording bell for great tone, intonation and projection, especially for outdoor concerts when the weather is moderate so I don't have to use my Kelly 18. As I recall, it was only about half again more expensive than their "stock" "18," since all they had to do was alter one parameter on their CNC machine. If you want one, all you have to do is contact Jim and ask for a "Pope" model 18 tuba mouthpiece.

hrender wrote:I know the cup is also larger in diameter (1.29" for the Kelly vs. 1.26 for the Bach).

That has changed through the years. When I got my first Kelly, it was advertised as 1.28. Then it was advertised a few years later as 1.285. Now, it seems to be advertised as 1.29. More reason to hang onto my original.

Apparently none of us have the answer BUT...

I have a random data point to contribute that might help?

I have a Kelly 18 that a 21/64 drill bit drops through with ease(sloppy) BUT an 11/32 drill bit can not pass through(not even with force).

Sooo.. the back bore is somewhere between .328 and .344 on this one.

A brand new Bach 18 sitting nearby readily accepts both bits.

Perhaps the Kelly's benefit from a smaller bore?

I'm probably not helpful.. but I agree Kelly did something right with this mouthpiece. They just work.

joh_tuba wrote:Sooo.. the back bore is somewhere between .328 and .344 on this one.

Am I right, that actually measures the "throat"? So the backbore could be larger, as alleged, though the throat is smaller as measured by drill bit.

(And of course there are parameters to look at - radius of entry to the throat, length of the throat, etc.)

I am no good at knowing the correct nomenclature for those parts of a mouthpiece and happily stand corrected.

Quickly veering off topic(sorry Elephant!) but seeking to understand this nomenclature thing:
Had assumed that the taper of the bore exiting the shank(backbore right?) was just a straight walled taper... likely created with a morse tapered reamer or similar. If that isn't true WHAT does a larger 'backbore' look like? Does the 'backbore' size move in tandem with the 'throat'? Sometimes? Always? Never?

I had imagined from a mouthpiece design machinist standpoint that the 'backbore' is mostly set in stone and that most of what differentiates mouthpieces would be in the 'throat', shape of the funnel entering the throat, and cup volume/shape, and rim shape.

Maybe identifying what the possible variables are will help me stare at these things on my desk and make some sense of it.

Stryk wrote:

the elephant wrote:
Further, or maybe separately, I like my Kelly 18. This is a big admission for me as I have always disliked the Bach 18 as well as all its various clones.

I know I am repeating myself here, but, I played a Mt. Vernon 18 for 35 years - they are NOT the same as the ones after that time period. I don't know WHAT is different, but something sure is. Perhaps the Kellys were modeled after that version?

The throat is way smaller on the old ones