As everyone knows (or at least, everyone interested in brass instruments), they come in two basic shapes: Cylindrical bore, where the tubing is a constant diameter all the way until the bell, and conical bore, where the diameter continually increases over the whole length after the valves. For some ranges, you can find both shapes, like the cornet and trumpet. But what’s the advantage of each? And why is it that you only ever seem to find bass horns in conical (i.e., the tuba)? And for whatever the benefit is to a conical bore, does the increase in diameter need to be steady, or would it work to have cylindrical sections joined together by tapered ones?
The reason I ask is because I’m planning on making my own tuba, but cylindrical tubes would be a lot easier.
The main difference seems to be in clarity of the harmonics as you go up the octaves. A cylindrical bore has a more precise delineation as to whether or not it will jump up an octave, so it’s probably going to give you clearer arpeggiations and leaps. A conical bore will have a more rounded tone due to being slightly more difficult to play precisely in tune (think of the difference between the trumpet and the flugelhorn–nobody uses a flugelhorn to play Bach).
If you’re also a woodworker, another option for lower conical instruments would be the squarpent.
The equivalent to a tuba with a cylidrical bore would be the Cimbasso. Basically, you would have a contrabass valve trombone.Cimbasso Sure would be groovy to have one in tuba shape.
If you’re looking to save money on a tuba, the link is to a very good site for new tubas. Extremely affordable and well made. They get very good reviews. I’ve had a couple students get them, and the’re very nice to play. (Not paid by Wessex. Of course, I’d be open to an endorsement deal. :D)
Keep us posted on your progress. Have you made a horn before? You can find good information on the major tuba message board, TubeNet.
The effect of a conical versus tubular bore is most obvious with the trumpet and flugelhorn. The tubing length is the same for both, but the trumpet has a mostly cylindrical bore, while the flugelhorn bore has a lot of taper (more even that a cornet). A trumpet has a much brighter tone than a flugelhorn because trumpets emphasize higher harmonics.
In this video a musician demonstrates the difference in sound between the two instruments.
Wow; that is an amazing difference between the two! I watched another with the cornet added and the differences between the three are incredible; much more variety in the sound than I even expected.
Well, of course I could buy a discount one, but what fun would that be? No, I haven’t done it before, which is part of why I want to.
And if cylindrical bores produce purer, brighter tones, then why does anyone ever make conical bores? Particularly for the bass, where tubas are far more common than cimbassos.
As I’m sure you’re aware, there’s an immense literature on the design and physics of brass instruments. Every aspect of the shaping makes a difference, which instrument makers undoubtedly learned by experience. But even the shape of the “bell” at the end has a profound effect on the harmonics. I’m vaguely aware of much of this, and, although I’ve played the trumpet for many years, I’ve never really looked into the physics of the thing. Making my own trumpet (or tuba) is a daunting prospect.
That said, this reference ( Cookie Absent ) claims that the “mellower” sound of flugelhorns and French horns is due to their having more conical portions than trumpets and the like. It gives a discussion of measuring the lengths of the various sections of different instruments and has plots of diameter vs. distance through the instruments. It doesn’t give results for a tuba, but I note that the Euphonium seems more conical than, say, a trombone (which is largely cylindrical). I don’t know about Tubas, which I would have guessed was more cylindrical. Having seen the Euphonium, I’m less certain. God knows what a Sousaphone would look like if uncoiled.
I can’t imagine getting any decent sound or durability in something made out of plastic Apparently you haven’t seen the Coolwind Tuba. NOT recommended.
I would bypass the making it myself part and check out instrument makers like Wessex and Mack Brass. One of the section mates in my band recently bought a Mack Brass Bb and it’s a nice horn for not a large amount of money, considering.
You can spend a ton of money on instruments if you want to – but you don’t have to. Also consider used instruments. You might not have a lot of options where you’re living, but if you’re really in the market you should go to a convention or a show and check out what’s on the vendor floor; that’s your best chance to go through a lot of choices. You just missed the ITEC convention in Iowa, but the next big show of tubas will be at the Army Tuba Euphonium Conference at Ft Myer (Washington DC) in February. Or a road trip to places like Dillon Music in Woodbridge, New Jersey. (You can get a flight to Newark and take the train to Woodbridge from there. Easy peasy.)
Come talk to me about this off list; maybe I have some other ideas for you.
But the most important part of a brass instrument isn’t made out of brass, or fiberglass, or plastic. It’s made out of air. And I will be using top-quality professional-grade air.
But again, ending up with a cheap instrument isn’t the primary point here. The primary point is making something just to see if I can.
CalMeacham, a trombone inherently has to be cylindrical, because it’s mostly slide, and you can’t make a conical slide. But take a look at the diameter of a tuba near the bell, and compare it to the diameter at the valves. There’s definitely a big difference there.
Though I will confess that I’m still a bit unclear on how a brass instrument ends up with the harmonic structure of an open-open tube (1-2-3-4… times the fundamental), when it’s closed on one end. I’ve been planning on dealing with that by just copying the dimensions of an existing instrument. But hey, if it doesn’t work, I’ll learn something.
But it’s not closed at one end. Think of it in terms of energy transfer. You can’t dump energy into a standing wave at a node. The closer you are to an anti-node, the more efficiently you transfer energy to it. A competent player will thus ensure there is an anti-node at the mouthpiece. This is done through control of the air pressure at and flow rate into the mouthpiece. As far as the standing wave is concerned, the boundary conditions are open because the player can’t produce a note unless they create those conditions.
(I played trombone throughout middle school, high school, and undergrad college.)
I would assume because “pure” and “bright” are not necessarily the timbres you always want. I, for instance, prefer the mellower, rounder sound of the cornet and flugelhorn to the brashness of the trumpet. It’s just another color in the orchestra. You wouldn’t just want to paint with a palette of fluorescent colors, would you?
