Not to belabor the obvious, but the euphonium and trombone are designed to produce sound. To become proficient with one of these instruments, it’s helpful to understand a little bit about the subject of sound.
There are three aspects of sound we need to be aware of.
First, there’s the physics of sound; how it works whether anyone is listening or not. The answer to the old question, “If a tree falls in the forest and no one is around to hear it, does it make a sound?” is “Yes.”
The falling tree creates vibrations in the air. Those vibrations obey the laws of physics. Physics doesn’t care if anyone is listening.
The physics of sound is called acoustics. During a program of private lessons, you would be introduced to more information about acoustics and related topics in the context of building skills on your instrument.
Second, there’s the human perception of sound. Our ears and brains don’t directly process sound as it exists physically. When sound waves reach our auditory canal, the vibrations are converted into signals that travel to the auditory cortex.
Exactly how we experience those sensations depends on factors such as our health, the sensitivity of our ears, our memory, and our psychology.
What we experience as “hearing” is a little different from what’s happening acoustically outside our bodies.
Interestingly, what we hear in our own heads when we speak, sing, or play an instrument is different from what other people hear.
Third, there’s the way sounds are formed and sustained inside our instruments and inside our oral cavity when we play.
This topic relates to the design and acoustical properties of the instruments we play.
This is a particularly important topic for euphonium players to understand, due to the intonation problems inherent in valved brass instruments. Those problems are exacerbated in larger instruments, such as euphonium and tuba.
Without going into too much detail, the issue is that the valve slides are of fixed length, while we need to add a proportional length of tubing to lower the pitch by a given amount. That is, we need to add more length in the lower register than the higher register.
So, the valve tubing lengths are a compromise - too short (sharp) for low notes, a little long (flat) for high notes, and more-or-less okay for the middle register. The intonation differences are easier to hear in larger instruments than smaller ones, so the problem is greatest for tuba and fairly significant for euphonium.
It’s important to understand the design trade-offs the instrument maker made in creating the model of euphonium you are playing, in an attempt to enable the instrument to be played in tune. The valve slides are of different lengths in different models - three-valve, four-valve, five-valve, and four-valve compensating designs.
In addition, instruments with different bore widths have slightly different acoustical properties. Different mouthpieces fitted into the receiver will affect intonation and how free-blowing the instrument is. On euphoniums with adjustable receiver gaps, different gap settings will affect intonation and other properties of the instrument.
The player must make adjustments specific to the type of euphonium as well as their mouthpiece and their embouchure to ensure good intonation. The adjustments may include selecting an appropriate mouthpiece, adjusting the receiver gap (if possible), lipping the pitch up or down, setting the tuning slides to appropriate positions, and choosing alternate fingerings in selected musical passages.
Besides all that, the intonation of the instrument changes as its temperature changes and as you warm up and then grow tired during playing sessions.
It helps to understand a little about musical acoustics.
Musical acoustics is a multidisciplinary field that includes elements of acoustics, human perception, instrument design, and musical concepts. There’s a good overview on Wikipedia here: Musical Acoustics on Wikipedia.
This page isn’t the right place to go into details about frequency, amplitude, wave propagation, and all that. You can read about that online or in books, and we can cover it in private lessons. For now, let’s just touch on a couple of basic points, to help clarify the inherent intonation problems of the euphonium and other valved brass instruments.
Say we have a vibrating column of air of a certain length. Exactly how the air was put into motion isn’t so important. Maybe we struck a key on a marimba, plucked a string on a viola, or played a note on a flute or clarinet or oboe or trumpet.
The length of the vibrating column of air is its wavelength or frequency.
The pitch we’re playing or singing is the fundamental frequency. Additional pitches also sound, although they are much softer than the fundamental and we don’t usually notice them individually. Those additional pitches are the harmonics of the fundamental frequency.
The harmonics are integer multiples of the fundamental frequency. When we play a note on an instrument, all the harmonics are produced. The characteristic timbre (recognizable quality of sound) of each instrument depends in large part on which harmonics are stronger (greater amplitude) and which are weaker (lesser amplitude) when we play that instrument. That’s how we can recognize when we’re hearing a bassoon versus a tuba versus a cello.
There is more than that in the sounds we hear. Instruments also produce overtones, which are frequencies higher than the fundamental but not necessarily integer multiples of its wavelength. Overtones also contribute to the characteristic timbre of each instrument.
But for purposes of this page, the harmonics are more interesting than the overtones. Harmonics are also called partials. On a plain brass tube without any valves, the lowest note you can play cleanly is the fundamental, also called the pedal tone. Its wavelength is equal to the length of the tube. That is, there is exactly one wave resonating inside the tube.
Using your embouchure to raise the pitch, the next note you can play cleanly is the second partial. Its frequency is one-half the length of the fundamental. There are two waves standing in the tube, each one-half the length of the tube.
When you play the third partial, the wavelength is one-third that of the fundamental, and there are three waves standing in the tube. Any guesses about the fourth partial? The fifth partial? I think you get the idea.
On a Bb euphonium, the fundamental is Bb1; the second partial is Bb2; the third is F3; the fourth is Bb3; the fifth is D4; the sixth is F4; the seventh is a flat Ab4, and the eighth partial is Bb4, or “high” Bb.
There’s more information about this on the page about euphonium instrument design.
Alone among the brass family, the trombone doesn’t have the inherent intonation problems of valved brass instruments. You can position the slide in exactly the right spot to get the correct pitch for any note. That’s the good news. The bad news is that you must position the slide in exactly the right spot to get the correct pitch for any note.
If you’re reading this as a way to get a sense of how it would be to work with me as a private teacher, just know that I tend to go into details like this. Don’t worry if it doesn’t interest you. You can “get by” without understanding it. There are plenty of amateur players who use the fingerings or slide positions they’ve learned by rote, and aren’t aware of musical acoustics.
They’re the ones who write the fingerings or slide positions on their sheet music, who struggle with sight-reading, who aren’t aware of alternate fingerings or slide positions, and who must ask the director whether they’re sharp or flat when the band is tuning. This level of detail is not necessary unless you aspire to advance beyond that level.
To be fair, not everyone does, and that’s fine. Many amateur musicians enjoy playing in community bands and orchestras as a social activity. I don’t think they need to take private lessons.