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to Bryan's home page Here is a new (2001) page I added on a Buescher helicon that I played in the Vergennes Vermont City Band. Take a look at the pictures -- it's a beautiful instrument.
This is a compilation of some interesting things I have read and asked about on the TUBAEUPH and BRASS lists. You can participate in these lists by going to:
Yahoo! TubaEuph Group or Sean Chisham's Tubenet BBS
Here is a index to this page:
From: Dan Masi (Dan_Masi@WARREN.MENTORG.COM)
> Could someone > please give a description of the merits of compensator versus non > compensator?
Better intonation. Here's a simple example of how it works.
We know that actuating a valve adds a *fixed* length of tubing to the horn's length. Without talking about intonation problems with the even-tempered scale, suffice to say that every pitch distance (half step, whole step, fifth, etc) bears a fixed frequency ratio, or percentage, to it's root, regardless of what the root note is.
Hmmm, that didn't sound too clear. Example time.
Imagine a horn that is 10' long. It has two valves on it, one which adds 1 foot of tubing, and one which adds 5 feet. The first valve, then, is supposed to add 10% length, and the second valve 50%. In real life, 10% wouldn't make much sense, as a whole step is about 12% and a half step around 6%, but these numbers make it easy. So, imagine that the first valve lowers the pitch by a whole step, while the second valve lowers the pitch by a perfect fifth (50% *is* the correct number for this).
OK. The horn plays beautifully at it's fundamental, at a whole step below (valve 1), and at a 5th below (valve 2). Now, imagine you're playing at a fifth below with valve 2 depressed. You're playing 10+5=15 feet of horn. According to our example, you'd need to add 10% length to get a whole step lower from here. So you press valve 1, and it plays way sharp. Why? Well, you started with 15 feet, and to add 10% you'd have to add 1.5 feet; BUT, valve 1 only adds 1 foot, so you're playing a 16' length instead of 16.5.
What to do?
Well, make valve 1 a bit fancier, add more holes and an extra .5 foot of tubing. Design it so that when valve 2 is pressed, pressing valve 1 not only adds it's normal 1 foot of tubing, but also adds the extra .5 foot, *compensating* for that huge length increase that valve 2 adds.
Dan Masi
From: Ian Phillipps (ian@PIPEX.NET)
I'd like to say that from a practical point of view, what this means is that the low notes, starting with C#, are sharp, for the reasons that Dan stated. On a trumpet, you use the trigger to flatten them - but on a tuba - well, imagine a tuba trigger :-)
If you have a fourth valve (Which is also a fourth valve, if you follow me :-) then compensation can make the fingering more flexible - you can use the 4th in conjunction with any other valves. Without it, you're limited to using 1+4 for C# and 4 for d or G.
You *really* need the compensation to play the notes between low F and the pedal notes.
[All pitches described as for a transposing instrument]
Ian
From: Bob & Barbara Ryan (74064.3261@COMPUSERVE.COM)
As you may have seen from some of my messages lately I am a great believer in "Compensating System" . I intercepted a message from a new chum ( thats Aussie for a lot of things) asking about Compensating system on the group and decided to subject you all (even if a lot of you already know) to my interpretation of life in the tonally centered lane. For the sake of the following argument please accept the use of the "he", "his", and whatever, as applying to tubaeuphs of either/all persuasion.
Your average cornet doesn't have compensating valves but what is sometimes seen (and almost always on trumpets) is third and/or both first slide finger rings which serve the same purpose but which must be operated manually.
The crux of the problem is this:
Sounding length is how long should a cylindrical tube be to sound the desired fundamental note. This equals the speed of sound (around 1100 feet per second) divided by the frequency of the desired fundamental note (say B flat = 208 Hz for a cornet) to give you the wave length, divided by four to give the quarter wave length (some 63 inches). The quarter since because the lips open up to add more air when the pressure is high at the player end and the pressure is low at the listener end where the pipe vents into the air. The actual length depends on the shape of the bore the average B flat trumpet running out around 53 -55 inches, trombones around 110 and real instruments vary so much because of the bore shapes I wouldn't have the foggiest notion but around 100 and 190 inches. Increasing bore makes the wave travel slower and the tube sounds longer than it's measured length (But see later for refernces who really know what they are talking about).
Well if you are still awake, you probably realised I only made up only about half of this story. Among the real story writers I have found much enlightenment ( and FUN ) in the following books published by Dover Books, see your local bookshop. ( I've bought about 6 of their music books and every one has been more fun than putting superglue on sackbut slides). Brass Instruments, Their History and Development, Anthony Baines. and if you are into tolerance and equality for the embrochoureraly challenged, a similar great book " Woodwind Instruments, Their History etc. by the same definitely not intellectually or humurously challenged author.
Horns Strings and Harmony, Arthur H. Benade
Fundamentals of musical acoustics, Arthur H. Benade
When the wind blows from the east I am an electrical engineer and Mr. Benade takes all the maths and physics I sweated on, then bypasses and subordinates it to understanding in a way that solidifies and of the lore and theory I have learned in 30 years of brass playing into a comfortable feeling that makes me feel that I think I am beginning to know what I am talking about (I think).
I congratulate you in your choice of instrument, if you had fun before strap yourself in.
All the best, Bob
p.s. my wife says I can't spell, butt eye thimc i ayent dooin 2 bard.
From: Ian Phillipps (ian@PIPEX.NET)
Bob & Barbara Ryan (74064.3261@COMPUSERVE.COM) wrote:
... a splendidly amusing an clear description of why compensation's needed...
But, I'd like to take issue with this:
> Sounding length is how long should a cylindrical tube be to sound the > desired fundamental note. This equals the speed of sound (around 1100 feet per > second) divided by the frequency of the desired fundamental note (say B flat = > 208 Hz for a cornet) to give you the wave length, divided by four to give the > quarter wave length (some 63 inches). The quarter since because the lips open up > to add more air when the pressure is high at the player end and the pressure is > low at the listener end where the pipe vents into the air.
I'm afraid your arithmetic's off by a factor or two or four. A trumpet's a full wave, not a quarter wave of its normal bottom note - 63 inches ~= 5 feet: 5 x 208 ~= 1100. The "fundamental" of a brass instrument is known to players as the "pedal", and isn't normally playable (not in tune, anyhow) on a trumpet. However, on our fine instruments it is, of course... A Bb Euphonium has a length of around 10 feet in its unvalved state, and produces a note of around 60Hz as its fundamental, or pedal.
Now, why is this a half wave, not a quarter? Here's a quick run down of wind instruments:
Open at both ends : flute, open flue pipes on organ. Overblows on the octave. Lowest note is a half-wave.
Open at one end: clarinet, closed ("stopped") flue pipe. Overblows on the twelfth. Lowest note is a quarter-wave.
Closed at both ends: brass instruments, oboe.
What, I hear you say, it's not closed! Ah yes, but there's something very non-obvious about the bell, which I can explain to Mr Ryan (a fellow sparks) as an impedance-matching transformer. The air in the tube is at high pressure, and low volume (high impedance); that in the world outside is high volume and low pressure (low impedance).
The reason that brass instruments produce such a greater sound than others for the same effort from the player is because of this transformer welded on to the end of the instrument. Woodwinds do have half-hearted apologies for bells, but they're not used most of the time because the air escapes through the little holes in the side.
So, from the point of view of the air in the tube, the bell makes moving the air into the outside world more difficult - hence what we have at the far end is a pressure antinode - high pressure, little motion. Looked at from the outside world, it's low pressure, large motion - just what you need to make a loud noise.
Without a bell, the brass instrument would behave as Bob says, but it would only sound the odd harmonics, the bottom of which would be an octave *below* the normal pedal note.
1/4waves: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 No bell: CCC G e a# d ! !! b Bell: CC C G c e g a# c'
Tubaeuph players can try this test: remove one of your slides, and play the instrument with as long a tube as possible, without a bell. The best slide is probably the main one, or maybe the 4th valve. You'll probably get some notes which are 3,5 and 7 on that sequence - you'll find two of them - 3 & 5 - separated by the interval of a sixth. If you go much higher, then the frequency is sufficiently high that the lack of a bell loses its value. The tuning will be lousy, so all this approximate.
The difference between half-wave and quarter-wave instruments shows why a clarinet can play an octave (ish) below a flute, despite being a similar length. The trumpet (ignoring the valves) goes down to the same pitch as these two, but is double the length, since its pedal note is unused. Hence the trumpet's lowest note is a full wave.
> three valve COMPENSATING Besson ( is there any other) Euphonium.
Sadly, there is :-(
Finally a thought for you all. Tonight, I as a member of a local British Legion band, will be commemmorating the dead not only of two "world wars" but other conflicts too. Please remember them; remembrance is not glorying nor the encouragment of war.
Remember, too, me, as I play with tired lips the pianissimo high G that starts "Sunset" at the end of the ceremony.
Ian
From: Ted Zateslo (zateslo@GEOMAG.GLY.FSU.EDU)
Bryan Cass (bc@VTF.IDX.COM) writes:
[...] > Was there another concert pitch back in the 20's > that required the use of two different tunings for instruments?
Yes: many older instruments were built to "high pitch", considerably above A440. Pitch wasn't standardized until this century (and some would say it still isn't, in certain performing groups!). Lots of old horns had tubing added (or extra pieces available for the tuning slides) to make them work at A440.
> > BTW, how can you tell if a horn has "compensating" valves?
Blaikley compensating valves, as found on Boosey & Hawkes low brass (and their imitators), have two valve loops in all the valves except the longest (3rd valve in 3-valve horns, 4th valve in 4-valve). Thus, externally, there are eight ports rather than the usual four in each valve casing, and the valve casings are considerably longer than on a non-compensating horn. There are also two loops of tubing coming from each of the compensating valves. (Some of the loops are too short to attach a tuning slide to: e.g., the 2nd-valve compensating loop on a euphonium.)
There are also compensating systems for rotary-valve instruments; they do the same thing acoustically, but have double rotors, just like a double (French) horn.
Ted Zateslo
From: Mark Sunderlin (sunderlm@IIA.ORG)
> tuned to A-440. Was there another concert pitch back in the 20's > that required the use of two different tunings for instruments?
First off, "concert pitch" has been on the rise over the years, with A=440 the current rage, but with it lower in prior years.
Second, n the past, before Korg, or even Strobocon (showing my age), the band tuned up to whatever pitchpipe, piano, or the lead cornet player played as concer pitch, so you had to be ready.
Finally, is that Helicon in Eb or BBb? is it possible your "extension" pipes, when taken out, put the helicon in another pitch? Maybe rasing it from BBb to CC or Eb to F?
> BTW, how can you tell if a horn has "compensating" valves?
If you have more than one set of tubing for each valve, the extra tubing
On Whatever day it was, Robert Engel wrote:
> Ok, if an instrument plays: open particial... b-flat f b-flat
d
> then what is it "keyed" in? Does anyone have a
chart or something?
> Robert Engel
> Lead Tuba - Shelby Sr. High School
There is a difference between transposing instruments written in treble clef, and "transposing" instruments in the bass clef. Treble clef instruments: The idea here is to keep fingerings the same for any written notes, regardless of the pitch of the instrument. Thus, on a Bb trumpet, playing a written C will result in a sounding Bb (hence the name "Bb trumpet"). On an Eb trumpet, the fingering for the written C is also all open, but because the music is transposed to keep fingerings constant, the sounding pitch will now be an Eb (again, the key of the instrument).
Bass clef instruments: All bass clef parts are ALWAYS written in concert pitch (i.e. the written note will always sound that same note). For we tuba players, there are four main keys our instruments are found in: CC (older notation for "2 octaves below middle C"), BBb (Bb two octaves and a whole tone below middle C), Eb (one octave and a sixth below mid C), and F (one octave and a fifth below mid C). But, our music is always written in C. The pitch-name of the instrument still refers to its fundamental pitch in its harmonic series, but because our written parts are not transposed, we must learn new fingerings for each of the above instruments. This is the same general idea behind trying to read C trumpet music on a Bb trumpet, for example. Thus, when any tuba plays an F, it will sound an F, but the fingerings will be different on the different pitched instruments. Going back to trombone, tenor trombones are in Bb (the fundamental note of its harmonic series), but their music is in C (that is why, unlike trumpets, the note C is not played in 1st position (=open fingering on trumpet)).
Long winded, I know, but that is the [mostly] entire story. ["mostly" because CC is in fact not the fundamental note of a CC instrument... CCC is the real fundamental. If this confuses you, reply to me directly...]
--
Now appearing on Centre Stage (at great expense to the Management)...
Scott Weaver
weaver@unixg.ubc.ca ae389@freenet.carleton.ca
sbweaver@freenet.vancouver.bc.ca aa992@freenet.toronto.on.ca
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