Euphonium Valves – Three, Four and Compensating Configurations and Understanding All of Them!
Brass instruments, in their simplest form, are simply tubes. At one end, a musician buzzes their lips to create sound, leaving the instrument at the opposite end. Any tube (even garden tubes as shown on YouTube) can produce wide intervals. These intervals are dictated by the harmonic series, trumpeters usually call it a partial series. In order to sound the notes between the partial series, the player must have a way to change the length of the pipe on the instrument. Some instruments, such as the trombone, have a movable slide, while others, including euphoniums, baritones, trumpets, and French horns, have valves to change the number of tubes through which air flows.
A valve is a device on many instruments that redirects airflow to a separate section of the tube before returning to the main tube. While depressed, this “extra” tube is in use, increasing the length of the working tube and reducing the pitch. On almost all modern trumpets, the valves work in the same way: the second valve lowers the pitch by a half-step, the first valve lowers the pitch by one full step (two half-steps), and the third valve lowers the pitch by one. step and a half (three half steps). If there is a fourth valve, it will lower the pitch by two and a half steps (5 half steps).
However, there is a small flaw with the valves. The 2-3 tube combination will be slightly sharp, the 1-3 combination will always be quite sharp, and the 1-2-3 combination will always be very, very sharp. Let’s explore why this phenomenon occurs.
Now you’re probably wondering how instrument makers know how many tubes to add to get the pitch down a half step. And if you’re not, I’m still going to explain it to you! Due to acoustic theory, to lower the pitch a half step, the working length of the instrument must be increased by approximately 1/15, or 6.67% of the working length. For purposes of explanation, I’ll be using an instrument that is 100 inches long (which is actually about the length of an euphonium). This means that the second valve should be 100/15 or 6.67″ long to lower the tone a half step. Now, to lower it a half step, you would add 106.67/15 or 7.11″ so that the first valve it should be 6.67″+7.11″ or 13.77 inches in length. Now let me explain that last statement, as it may have thrown some of you off guard. The reason the first valve would not simply be 2 (6.67) is that to step down a full step, there must be enough tubing to step down a half step (6.67″), and then enough tubing to step it down. tune half step (7.11″). This same theory applies to the third valve and produces a length of 21.36 inches.
The formula for the theoretical length of tubing, TL, required to reduce a given number of half-steps, x, for an instrument of length L, is TL = L(16/15)^x. Example: 100″ instrument down 3 semitones: TL = 100(16/15)^3. TL = 21.36.
Therefore, tube instruments are set up so that each tube, individually, is in tune. Problems occur when players must use tube combinations to adjust the pitch by more than three semitones. As you can see from the calculations above, each time you add another half step, the working length should increase by more than the previous increase. Using the example of a 100″ instrument, the third valve increases the length to 121.36″ to produce a note tuned three semitones below the original pitch. To step down a half step past this note requires 8.09″ of tubing. However, since the length of the second valve is only 6.67″, this combination will be slightly steep. This problem is only compounded and in the 1-3 and 1-2-3 combinations, the shortfall between the actual length and the “tuned” length is 2.94″ and 5.04″ respectively. As you can see this creates quite a problem, in fact the 1-2-3 combination is almost a sharp fourth step!
The 4th valve fixes some problems and adds others. The fourth valve adds 38.08 inches of tubing for our 100″ instrument. This is a substitute for the 1-3 combination as the fourth valve has the correct amount of tubing to be in tune. Likewise, the 4th valve -2 produces a more in tune pitch than 1-2-3 since it’s only about 2.54″ short of theoretical length. So this is great, now we have all seven common combinations relatively in tune right? This is true However, this 4th valve gives access to a range that three-valve instruments cannot achieve.By using combinations with the 4th valve, euphoniums can reach notes like D below the staff, a note that is not possible using three valves. Now we come to the curse of the fourth valve. When the fourth valve is used in combination with other valves to achieve these low notes, the problem described above is further complicated. To lower the pitch one full step after pressing the fourth valve, 19.02″ should be reached. added in addition to the length of the fourth valve. In general, the first valve would reduce the pitch by one full step, but remember the tube length of the first valve? 13.77 inches. Again, this problem worsens as more valves are pressed. Using the 1-2-3-4 combination, which using the valve half step definitions, should provide a B natural half step above the Bb pedal. However, the pipe length for a low B natural is a whopping 203.38 inches. ! The combined length of all four valves only equals 173.22 inches… That’s enough for a slightly sharp C! That’s right, that means B natural is not possible (without the player’s lips) on a non-compensated 4-valve euphonium.
Four valve compensation system
So how do we explain all this lack of piping when more and more valves are being pushed? The answer is the compensation euphonium. Compensation euphoniums draw air through a “double loop” when the fourth valve is depressed. What that means is that when the air leaves the fourth valve slider, it actually goes back into the valve block. In this second step, there are smaller compensation loops that the air passes through, if the 1st, 2nd or 3rd valve is pressed in combination with the 4th valve.
The beauty of this system is that because the offset loops are dependent on the fourth valve being pressed, the first 5 fingerings (2, 1, 3, 2-3, 4) remain unchanged as your intonation is satisfactory. . However, as you go further down (2-4, 1-4, 3-4, 2-3-4, 1-3-4, 1-2-3-4) an additional compensation loop is added to each valve. This brings the pitch of these fingerings to satisfying levels.
The offset system also has another added benefit: when playing below the staff, players can use conventional fingerings in addition to the fourth valve. For example, on an uncompensated euphonium, a player would have to play a D below the staff with the fingering 2-3-4. However, AD in the middle register is fingered with 3. With the addition of the offset loops, a player on an offset euphonium plays a D below the staff by simply adding the fourth valve to 3.
Why does this seem so confusing?
At this point, your brain is probably spinning. That’s okay because as an artist you don’t have to know why the compensation system works. You don’t need to know the mathematical and acoustical theory behind what happens when you press tubes 1, 3, and 4. A compensating euphonium does all the work for you. Solves intonation problems created by tubes. For an offset euphonium, you don’t need to change conventional fingerings when playing below the staff.
Take a professional tuba, for example. These tubas can have five, six, even seven valves for playing a low chromatic range! You do not believe me? Find a Mnozil Brass video on YouTube and stop at a close up of the tubist. There are seven valves on your instrument! The fact is that compensating euphoniums provide a chromatic range with just four valves, while non-compensating instruments could only achieve that feat with the addition of one or two extra valves.
Fourth Valve Placement
Look at a Yamaha YEP-321S, then look at a YEP-842. Besides the gold accents on the 842, the most obvious difference is the location of the fourth valve. The 321S has its fourth valve next to the third valve; this arrangement is called an online arrangement. On the other hand, the 842 has its fourth valve on the right hand side, roughly at the midpoint; this arrangement is called a 3+1 arrangement. In the case of in-line valves, the fourth valve is actuated with the right little finger. For instruments using a 3+1 arrangement, the fourth valve is operated by the left index or middle finger. Using the fourth valve with the right little finger can be problematic when adding combinations like 2-4 due to lack of strength in the little finger. Therefore, from a physiological point of view, a 3+1 system is usually easier to operate, especially in fast passages.
All offset euphoniums are 3+1 (however, not all 3+1 offset euphoniums are offset), which provides an additional benefit. Euphoniums are tapered bore instruments, which means that the bore is increasing until it reaches the end of the bell. The exception to this is on valve slides (1-2-3 on all horns and 1-2-3-4 on non-compensated four-valve instruments) where the bore remains constant. By moving the fourth valve further down the horn, the hole can expand as you get closer to the fourth valve. This additional expansion allows for a more general taper design and provides a more characteristic euphonium sound.
So which euphonium is right for me?
Most students will start with a standard three valve system. This makes the horn lightweight, free blowing, and doesn’t overcomplicate the horn. For beginners the three valve euphonium is the best choice, however as the player develops it should be upgraded. Most high schools will purchase four-valve “in-line” uncompensated euphoniums for their students. A compensation euphonium costs much more and makes no difference in anything except intonation in the low register. When buying a personal euphonium, if you know you’ll never need the offset record, then there’s no need to pay the extra money for it. However, I would suggest getting a trim horn if only because it’s better to have it and not need it than to need it and not have it. As far as valve placement, I’ve found that most people prefer the 3+1 inline arrangement. The 3+1 arrangement is simply much easier and more comfortable to operate.