Brass instruments, in their simplest form, are simply pipes. At one end, a musician hums their lips to create sound, which leaves the instrument at the opposite end. Any tube (even garden tubes as shown on YouTube) can produce wide ranges. These intervals are dictated by the harmonic series, trumpeters generally 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, like the trombone, have a moveable slider, while others, including euphoniums, baritones, trumpets, and French horns, have valves to change the number of tubes the air flows through.

A valve is a device on many instruments that redirects airflow to a separate section of tubing before returning to the main tube. While pressed, this “extra” tube is in use, thus increasing the length of the working tube and reducing the pitch. On almost all modern trumpets, the valves work the same way: the second valve lowers the pitch by a half step, the first valve lowers the pitch by a 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 valve 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 in order to lower the pitch by half a step. And if you’re not, I’m still going to explain it to you! Due to acoustic theory, to lower the pitch by half a 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 will use an instrument that is 100 inches long (which is actually about the length of a euphonium). This means that the second valve must be 100/15 or 6.67″ long to lower the pitch a half step. Now, to lower it a half step, you must 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 puzzled some of you. The reason the first valve wouldn’t just be 2 (6.67) is that to step down a full step, there must be enough pipe to step down a half step (6.67″) and then enough pipe to step it down. tune half a 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, valved instruments are set so that each individual valve is in tune. Problems occur when players must use valve combinations to adjust the pitch by more than three semitones. As you can see from the calculations above, every time you add another half step, the working length should increase more than the previous increase. Using the example of a 100″ instrument, the third valve increases in length to 121.36″ to produce a note in tune three semitones below the original pitch. To lower the pitch a half step past this note, 8.09″ of tubing is required. 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 solves some problems and adds others. The fourth valve adds 38.08 inches of tubing in the case of our 100″ instrument. This is a substitute for combination 1-3 since the fourth valve has the correct amount of tubing to be in tune. Likewise, combination 4 -2 produces a more in-tune tone than 1-2-3 since it’s only missing about 2.54″ of theoretical length. So this is great, we now 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 reach.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 pr depress the fourth valve, 19.02″ should be reached. added in addition to the length of the fourth valve. In general, the first valve would lower the pitch by a full step, but remember the tube length of the first valve? 13.77 inches. Again, this problem gets worse as more valves are depressed. Using the combination 1-2-3-4, which using the valve half-step definitions, should give a B natural half a step above the Bb pedal. However, the pipe length for a low natural B 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 that B natural is not possible (without the performer’s lips) on a 4-valve euphonium without compensation.

Four-valve compensation system

So how do we explain all this lack of plumbing when more and more valves are pushed? The answer is the offset euphonium. Offset 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 slide, it actually goes back into the valve block. In this second step, there are smaller compensating 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 depend 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 offset loop is added to each valve. This brings the pitch of these fingerings to satisfactory 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 simply by adding the fourth valve to 3.

Why does this seem so confusing?

At this point, your brain is probably spinning. That’s fine because as an artist you don’t have to know why the compensation system works. You don’t need to know the mathematical and acoustic theory behind what happens when you press valves 1, 3, and 4. An offset euphonium does all the work for you. Solves intonation problems that valves create. For an offset euphonium, you don’t need to change conventional fingerings when playing below the staff.

Look at a professional tuba, for example. These tubas can have five, six, even seven valves to play a low chromatic range! You do not believe me? Find a video of Mnozil Brass on YouTube and stop at a close-up of the tuba player. There are seven valves on your instrument! The fact is that compensating euphoniums provide a chromatic range with just four valves, whereas non-compensating instruments could only accomplish that feat with the addition of an extra valve or two.

Fourth Valve Placement

Look at a Yamaha YEP-321S, then look at a YEP-842. Aside from 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 layout is called an online layout. On the other hand, the 842 has its fourth valve on the right side, roughly midway; this arrangement is called a 3+1 arrangement. For 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 gauge instruments, which means that the gauge gets larger and larger 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 inside diameter remains constant. By moving the fourth valve further down the horn, the hole can expand as it approaches the fourth valve. This additional expansion allows for a more general tapered design and provides a more distinctive euphonium sound.

So Which Euphonium Is Right For Me?

Most students will start with a standard three valve system. This makes the horn light, free blowing, and doesn’t overcomplicate the horn. For beginners, the three-valve euphonium is the best option, however, as the player develops, it should be upgraded. Most high schools will buy four-valve “in-line” uncompensated euphoniums for their students. A compensating euphonium costs much more and makes no difference to 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 one and not need it than to need one and not have it. In terms of 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.