How Musical Instruments Work

really recommend you check it out. It will give you the underlying principles on what I'm gonna build on today, and it's gonna give a lot more of what I'll be saying in this episode more context. However, you're like, yeah, no,

I'm good, let's do this. I'll just say this. Remember that playing any note on most musical instruments produces a fundamental frequent See that's the note that we hear that's being played, as well as a series of overtone frequencies, and it's those overtones that shape the sound and give it the quality we associate with that specific instrument. We call it timber. And that's why a C note played on a flute sounds different than the same C note played on a recorder or a guitar or a xylophone.

If it weren't for these overtones, the notes played on instruments would sound more similar to one another. There'd be no real point in making different instruments. But as we know, musical instruments have their own distinct qualities. Before we move on to specific groups of musical instruments, I do want to talk a tiny bit about music theory, but only a tiny bit, because one, music theory gets really complex and very specific and it requires a lot more discussion

than I can cover in an episode. And two I get really lost in the weeds pretty early on with music theory. If I'm being on a I am not a musician. I've never taken courses in music theory. All the learning I've done has been on my own, and I am admittedly a novice in the field. But while I've talked about frequencies and pitches and stuff, I haven't really talked about why we have specific notes in Western music.

Why do we have the notes we have. The notes in Western music are A A sharp, B, C C sharp, D D sharp, E, F F sharp, G n G sharp. Each of those represents a specific frequency, or rather I should say frequency s because you can have different octaves of the same note. Right, you can have an A

and then go up an octave. You still have an A, but it's twice the frequency of your previous A. Each note in this sequence is a semi tone apart from the previous note, as well as a semi tone apart from the following note, and collectively it's called the chrome matic scale. Now I could have started on any one of those notes, and after the letter G you wrap back around to the letter A and get back to

my starting point. That's still a chromatic scale, but it raises a question like why is there an A note? Why does the sequence go up to G? Why do all notes except B and E have sharp notes? What even defines a note? These pitches correspond to frequencies that Western musicians and audiences have found appealing over time, and so it kind of solidified out of what people liked. There are other music scales, by the way, such as

the diatonic scale. While the chromatic scale includes the twelve semi tones found in Western music, the diatonic scale is a scale of seven notes, five whole tones, and two semi tones and do re mi fa, so lat do that little bit you've heard if you've ever listen the sound of music that represents a diatonic scale. And it

gets way more complicated than all this. But to really dive into that, we'd have to go into a whole history of music and the development of music theory and philosophy, and we'd have to talk about ratios and major keys and minor keys, and honestly, it's way more than what we really need to consider for this episode. The important thing for us to note, ha ha ha, is that the pitches represented in the chromatic scale tend to be the ones that Western musical instruments are designed to replicate

when they are properly tuned. So you can think of musical instruments as being a reflection of our natural kind of affinity towards these particular notes in the West. And I have to keep saying that because music, while it is a universal thing among humans that you know, we make music, it's not a universal set of laws across all cultures. All right, I got all that out the way. Let's talk about the general classifications of modern instruments, and

for the purposes of this podcast. Again, I'm just talking about the typical instrument groupings that you would find in a Western orchestra. And I realized this brings a lot of cultural baggage into the discussion. But just know that the examples I give are meant to represent large groups of instruments across different cultural boundaries that share, you know,

similar qualities. If after I cover all the major classifications in Western orchestras, I have a bit of extra time, we'll tackle some stuff that isn't typically part of those ensembles. There's one in particular that I know I'm going to cover that you don't typically find in an orchestra. Now, out of all the categories of those musical instruments, I

would say percussion is the easiest to explain. Now, I do not mean it's the easiest to play by any means, because I think playing any musical instrument requires skill and lots of practice and dedication, especially if you want to do it well. Also, you've got to remember that my original co host and the co creator of tech Stuff, Chris Palette, is himself a talented drummer. He played professionally and stuff, and while I always like to give him a bit of the business when it comes to drumming

and whether or not it counts as music. In truth, I acknowledge that being a great percussionist is really to be an accomplished musician. Percussion instruments are, of course the kind you strike or rub or otherwise you know, cause to vibrate directly, and they're probably the oldest subset of musical instruments, as it seems like we'd probably figure out pretty early on as human beings that if you hit that thing with that other thing, it makes a pretty

cool sound. But this is all a guest based on intuition. We really don't know when humans first started making music, except it was definitely before last Wednesday. Percussive instruments produced vibrations, as I said, after being struck or rubbed or scraped. And there are a couple of instruments that occasionally get grouped with percussion, perhaps because it's hard to figure out where else to stick them because they aren't your traditional instruments.

But I'm going to ignore those because they are the outliers. So generally you're talking about stuff like drums, xylophones, symbols, that kind of thing. There are also instruments that span percussion and other categories like stringed instruments, and the most obvious example of this type of instrument is the piano or the piano forte. Because the piano has strings, obviously, but those strings are struck rather than plucked or strummed

or bode. There are little hammers inside the piano. They swing when their respective key is pressed on the keyboard, and the hammer strikes its respective string, which then vibrates at its fundamental frequency. And that's determined by a lot of stuff, including the length of the string, what the string is made of, the thickness of the string, and

how much tension is on it. But a standard piano has a D eight keys, some have more, many have fewer, but that means they also if they have a D eight keys, they have a D eight strings and usually eighty eight hammers. Will transition over to stringed instruments in a second since we're on the subject, but really, percussion is is one of the simplest ones for me to

explain from a physics perspective. The only other thing I might mention is that some percussion instruments are said to be pitched, meaning they can produce musical notes of one or more pitches, and some are considered unpitched, meaning they produce a sound of indefinite pitch. So a xylophone is a pitched percussion instrument, as each wooden bar produces a

different pitch when you strike it with a hammer. Symbols or shakers or bass drums and similar instruments are said to be unpitched, and this is a good time to talk about why some sounds are considered unpitched. Some sounds consist of numerous frequencies at similar levels of amplitude, and

amplitude is volume. You know. Remember in the previous episode I was talking about overtones and how most musical instruments produce not just a fundamental frequency, but several other frequencies, and those other frequencies are typically at much lower amplitudes than the fundamental, so we don't hear them as distinct pitches. But some instruments produce multiple frequencies of sound at near

equal amplitudes, and we get this weird combination effect. Audio engineers will talk about the color of noise, and you've likely encountered examples of this, such as white noise or pink noise. White Noise is any collection of equally spaced frequencies of sound within a specific bandwidth, all at the same amplitude. So the high frequencies and the low frequencies all are at the same volume, and you get that white noise. This is going to come back to play

a little bit later. The other colors of noise describe distributions of amplitude that either increase or decrease with bands of frequencies, so that you get louder high frequencies than low frequencies. That's pink noise, or you get the opposite, you know, higher low frequencies than than the high frequencies that would be blue noise. So unpitched percussion instruments produce

sounds that are closer to noise. Not that this means they are unpleasant, but rather the frequencies of sound they produce are such that we do not perceive a specific note or pitch with them. Now that we've got the bing, bang boom stuff out of the way, let's talk about instruments that use either strings or air to create sound. And if we peek at the physics behind these instruments, we're going to see that they rely on the same

underlying thing, which are called standing waves. So what is that, Well, there are different kinds of waves. You've got traveling waves, So these are waves that start at one point and then they travel down through whatever medium they're going through. If you had a way of seeing the wave, you would actually watch as it started at a point of origin and move all the way through its medium. You could follow it from start to finish. Standing waves are

a bit different. This is another tough concept to get across without visual aids. But imagine you've got a slinky and you've attached one into the wall, so you've you glued one end of a slinky to wall. Don't actually do this, and then you stand far enough back where you've stretched the slinky out from the wall to you so it's nice and tight, and you send a quick pulse by moving the slinky up and then down, and

you just whip it down the length. You would be able to watch that go all the way to the wall. It would hit the wall, and then this pulse would reflect off the wall. But because that that side of the slinky is actually anchored to an unmoving point, uh, then that reflection will get inverted. The pulse will be as if it were a down then up as opposed to an up then down, and it will come back

the length of the slinky. Now, let's say just as the wave is reflecting, you introduce a second pulse down the length of the slinky in the original orientation of the first pulse, So you're going up and then down. Now, that mean that these two pulses, as they're traveling toward one another, are inverted with respect to each other, and once they pass through the center point, they undergo what's called destructive interference. In the very middle of the slinky,

you would have no movement. It would be equilibrium, and the two pulses would pass through and continue on for the rest of the length of the slinky, But that little middle point, which we would call a node, wouldn't move. So the points in a standing wave that maintain equilibrium that do not oscillate are the nodes. The oscillating points with the greatest amplitude or deviation from the equilibrium are called anti noodes. And you can actually see this on

the string of a guitar. If you were to strum a guitar string and slow things down, you'd see all the points along the string that are still relative to the links on either side. They're going up and down, like if you were doing this super slow motion with a strobe light effect, you would really be able to see it, and it's kind of trippy. And that is a standing wave. The wave does not appear to move.

You see the peaks and troughs going up and down, but you have these fixed points, these nodes that are not moving, and so the wave doesn't seem to be moving down the length of the medium. It just seems to be this up and down oscillation on either side of these anchored nodes. So that's a standing wave. And wind instruments do this just like stringed instruments do, except in wind instruments we're talking about the movement of a column of air that's the medium, as opposed to a string.

So instead of a physical string between two anchor points, we're talking about a column of air inside an instrument, and we're going to get back to that a little bit later in this episode. Alright, so let's get to those stringed instruments. Producing notes on stringed instruments involves plucking, strumming, bowing, or otherwise causing strings to vibrate, which produces the corresponding

sound of the musical instrument. The sound produced, as I mentioned with the piano, depends upon the length of string, what the string is made of, how thick or stiff the string is, and the amount of tension on that string, Plus the overall design of the musical instrument matters as well, such as whether or not the instrument has a resonance chamber. Okay, so some general rules. Let's say that you've got two strings.

They're made out of the exact same material, they have the same thickness, they are under the same amount of tension, but one is longer than the other one. The longer of those two strings will produce the lower note when you strum them. But if you have two strings that are of the same material, they're the same thickness and they're the same length, whichever one has more tension on it will produce a higher note. It will vibrate at a higher frequency, So the tighter string will vibrate faster

than a looser string. If you have two strings that are made of the same stuff, they're the same length, they're at the same tension, but they are a different thick nous, you've got one that's thicker than the other. The thicker string will produce a lower note than the thinner string. It will vibrate more slowly. You've got more

mass there. So on an instrument like a guitar, you can have all the strings be the same length right there, the same length from nut to bridge, right the top of the neck, all the way down to the base of the strings. They're all the same, they aren't stopping at different points. So on an instrument like a guitar, you can have all the strings be the same length from the top of the neck down to the very base of the strings. All those strings are the same length.

They stretch the entirety of the fretboard, but each of those strings are of a different thickness and a different tension. To have each one tuned to a specific frequency a vibration that represents a specific note. Tuning a guitar consists of adjusting the tension on those strings. So the tuning pegs are all about either increasing the tension by turning the tuning peg to tighten the string, or decreasing the tension by turning the peg the other direction to loosen

the string. And strings get out of tune over time. They may stretch because of the fact that it's a you know, elastic material like the nylon strings you might find on the ukulele, or it could be environmental factors like the temperature or humidity. Those can all affect them. When we come back, I've got more to say about stringed instruments and how they work, but before we get

to that, let's take a quick break. There are several stringed instruments that have a single fixed string dedicated to each note within the instruments range. So a piano is a great example. You've got your standard eighty eight notes on a typical grand piano. Harps also fall into that general category. There are some bode liars that can work a little differently, but most harps are the same way,

where every string is dedicated to a specific note. So musicians who play these instruments have to manage way more strings, but they don't have to make any big changes to those strings. They don't have to alter the strings length to produce different notes. They just plug a different string.

But other stringed instruments like the guitar family, or violins or cellos, viola's stuff like that, they require players to change the length of the strings by pressing down on the neck of the instrument, you know, pinching the string and thus changing the anchor points for that string. Changing the length of the string changes the strings vibration frequency, thus changing the pitch. Guitars have a fretboard, with the frets providing that anchor point for the string at specific intervals.

Makes it really easy. The frets are space such that playing an open string and then playing each fret moving up the neck toward the body will follow the chromatic scale. Each fret is a semi tone apart from the one before and the one after it. I can actually demonstrate this. I am going to uh play up the scale on the G note of my cigar box guitar. So this is the open string and the first fret would be a half tone or a semi tone up, and then

the next one and next m Yeah. So just by altering the length of the string you have changed how frequently it will vibrate and us increase the pitch. If you ever ever see anyone doing air guitar and they're moving their hand back when the guitar pitch is going up, they're doing it wrong. Pianos are similar to guitars in the sense that if you play twelve consecutive keys, including both the white and the black keys, you play the

chromatic scale. Each key in sequence is one semi tone apart from the one before it and the one that comes after it. Bode String instruments like the violin are different from instruments like guitars in several important ways. The musician plays the instrument by drawing a bow strung with horsehair, typically with a coating of rosin on it to increase friction, and they draw this horsehair against one or more strings

on the instrument like a violin violence. By the way, you have four strings, a standard guitar has six, and when you do this, when you draw the horsehair against the string, it causes that string to vibrate. Unlike a guitar, the violin and instruments like it don't have a fretboard. They have what are called fingerboards, but there are no frets on them. Musicians can still change the length of strings by pressing down on them, similar to a guitarist,

but without the frets. It involves learning the relative positions of where your fingers need to go on that fingerboard and requires a lot of muscle memories that you can, you know, replicate notes accurately, wind bode the strings. Vibrations transferred to the body of the violin through the bridge that's the part at the base of the strings, and it goes down into the body of the violin through what is called the sound post, which is in the

resonance chamber. The sound boast is both to transmit vibrations from the top of the violin to the the back of the violin and make the whole body vibrate and resonate, but it's also meant to support the top of the violin. There's a lot of pressure on the top of a violin because of the tension that's on those strings. The sound emerges from holes that are in the top of the violin's face. These are called f holes, and the

resonating body amplifies the sound of the strings significantly. Many stringed instruments have resonance chambers which helps amplify and direct sound. In fact, the cigar box guitar I was just playing has a resonance chamber. That's the box, the actual cigar box, and the The luthier who made my cigar box guitar has cut a hole in that box so that the

sound can reson nate outward. If you don't have a resonance chamber, then the vibrating strings would be pretty quiet and it would be difficult to hear it over other instruments. The way you produce vibrations with a stringed instrument, whether it's by strumming or plucking or boeing or striking the strings, will help shape the sound as well the strings themselves and the design of the instrument as a whole. So all of these things contribute to the specific overtones that

are created when you play that instrument. And that's why each of those instruments sounds different from the other instruments. Whether it's a banjo, guitar, lute, mandolin, harp, piano, violin, or whatever. It's the specific qualities of those types of instruments that gives each one its own sound. Another thing that shapes the quality of the sound is whether the strings are doubled. Some instruments double up on strings for

specific notes, like the mandolin tends to do this. I think it was done that way in order to make my fingertips cry, but really the more likely original reason was it was done to amplify the volume of sound, because as instruments got louder, people had to figure out ways of making older instruments be able to play along

with newer, louder instruments. And some of you may be wondering why I'm bothering going through all this stuff, and it's really just to illustrate that over time, we've really learned how to shape instruments so that they can harness the power of physics, even before we had a full

understanding of those physics. And this required an enormous amount of trial and error as people learned what did and didn't work, and then taught this to younger generations who improved upon previous methods while learning more about the actual science behind the practice. The reason I went with stringed instruments after percussion is that it's pretty easy to get your mind wrapped around what is creating the sound, because

ultimately it's the vibration of those strings. Although those strings could be feeding vibrations into some other part of the musical instrument, but we can see the strings vibrate, So this one's pretty easy to grasp. You know, you see it and you're like Oh, that's what's making the noise. But what about instruments that you blow into. Well, it helps if we continue our division of the instruments into

their classifications. So I'm going to go with woodwinds next, which confusingly also includes instruments like the flute, but more on that in a second. First, we know sound ultimately relates back to vibration. There are a few different basic types of woodwinds that create vibration in different ways, and I'll start with read instruments. These instruments typically have a mouthpiece, though some double read instruments don't have a full mouthpiece.

But the instrument has a read, or sometimes two reads, and those those reads vibrate when you force air against them in a specific uh direction. If you're force sing an airstream against them properly, you cause the read to vibrate, and as the vibration of that read, that ends up causing the oscillations of air pressure that's going into the instrument, the fluctuation the wave of air pressure. So the source of vibration for these read instruments are the reads themselves.

That's pretty easy to understand. But what about instruments like the recorder? Or the penny whistle or the flute. These don't have reads. There's no obvious physical element in the instruments that's vibrating. So what is creating the vibrations that make the sound. Well, I'll start with the humble recorder, which I remember playing way back in middle school, shortly

after the recorder had been invented. I'm kidding, I'm not that old, but my former co host Lauren would have made that joke, So this one goes out to her. If you look at a recorder, you'll see that below the mouthpiece on the body of the recorder is a notch, and that notch is a piece that some people call

the ramp. If you were to cut the recorder in half, down the full length of the instrument, you would see that the ramp is like this shelf like structure that comes to a point, and the point faces the mouthpiece. The mouthpiece itself leads to a very narrow passage that's called the wind way. It's it's narrow so that it forces the wind through a very narrow channel. Blowing into the recorder forces air down this wind way. Then the air hits the edge of this ramp, and here's where

the vibration happens. When the stream of air hits that sharp ramp, some of the air deflects up out of the instrument, so up the ramp like dukes of hazard going off the highway. Some of the air, though, continues into the air column that's inside the recorder's body, the bore of the recorder, so it continues forward, and the oscillation of the jet of air is what creates the basic vibration within the recorder. It's the source of the sound.

I'll get to what's going on in the body of woodwinds in a minute, because that bit is standard across the board to some extent. But first I want to chat about how a flute creates vibrations. Now, when I say flute, I'm specifically referring to transverse or side blown flutes. If you were to look at the mouth hole for the flute, you would see it has a sharp edge. This acts very much like the ramp in a recorder. So if you blow down properly on the mouthpiece, you

create an edge tone. The frequency for the main edge tone depends upon the velocity of the stream of air and the distance from the air stream to the edge, so with a recorder, this would mean changing the length of the wind way, which you can't really do because it's a physical structure. But with a flute you can actually do that. You can roll the flute so it's a little closer to your lips or a little further away, and you can actually shape the edge tone that way.

This becomes important because by varying both the velocity of the air dream and the distance between the edge and the lips, a flow disc can vary the flute pitch. This is called overblowing. But to understand that, it's time we talk about what's going on inside all these different instruments once the oscillating air molecules are in there. So think of a cross section of a woodwind instrument. Imagine

we can visualize what's happening inside of it. And let's think of flutes and recorders, because these are types of open ended tubes like a pipe you would use in plumbing. If you were to stop up the end of the instrument, you would have a closed ended tube. And something interesting happens that I'll get to in a moment. Now. Before we play our recorder or our flute, the air inside the instrument is at a pressure that's equivalent to the

ambient atmospheric pressure. That is, the pressure inside a recorder or an oboe, or a clarinet or a flute. It's the same as the air pressure inside the room. And it's like that as long as it's not being played. As soon as you start blowing into the instrument, you're introducing waves of increasing and decreasing air pressure. Those fluctuations that were caused by the read and the read instrument, or the ramp of a recorder or the mouthpiece of

the flute, for example. At either end of instruments like the flute or recorder, you have the anti noodes. Now, remember when I was describing standing waves. The anti noode is where you get the big fluctuations and amplitude. So at the anti noode you've got low air pressure and maximum movement of air so velocity uh so. And this is all with respect to atmospheric pressure in the center

of this air column. So in the center of the bore of your flute, let's say, in between the anti noodes that are at the ends, you've got the node. This is an area of high air pressure and very low or no velocity with respect to atmospheric pressure. So this is the opposite of what we saw with stringed instruments, because with those is really easy for us to imagine right, the anchored points at either end of a string are nodes.

They cannot move right, so they're locked in place. The bits that wobble about on the string are further in from those points. That's where the anti noode is. It's very easy to visualize, but with an instrument like a flute or recorder, that lockdown part is actually in the middle. It's in between the anti noodes. The ends of the air column are the parts oscillating, and the bit in

the middle is remaining an equilibrium. This is actually how the air column inside the instrument is vibrating, and the frequency of that vibration determines the fundamental frequency or tone we hear coming from that instrument. So this column of air inside the instrument is vibrating many times per second. If we were doing this with a recorder, we would start with all the holes on the recorder covered right,

so we don't have any holes uncovered. This creates the maximum length bore for the recorder blowing into the mouthpiece of the record or would force an air stream against the ramp, which would create this oscillating effect that would start the vibration pattern down the bore of the recorder. Somewhere near the center of the bore would be the note where the air pressure is that the highest and the air velocity is at its lowest. The vibration would

create the note we hear played by the recorder. But what if we open up one or more of those holes that we've covered up. Well, if you do that, you're decreasing the length of the air column, just as pressing down on the guitar's fretboard effectively reduces the length of the vibrating string and increases the frequency or pitch. So the holes in a recorder aren't quite big enough to have an open hole completely cut off the air column at that point, But that ends up getting a

little too deep into the physics of recorders. Basically, if you have a recorder or a penny whistle and you blow, as you start to lift fingers off the holes from the far end and you move up the instrument, you'll hear the notes in increasing in pitch as you do so. By taking your thumb off the thumb hole on the underside of the recorder. You divide the air column into two parts, which means you get two notes inside the recorder,

not just one. And the vibration the frequency has increased again because those air columns are shorter, just as if you had a shorter string vibrating. So you get to you a second register of notes in the recorder. With a really well designed recorder, you can get up to four registers or thirty notes playable on an instrument with just eight holes, which is pretty amazing. And it's all because of the physics of these standing waves of air

pressure inside the instrument. Now, when we come back, I'll explain how instruments like the clarinet and the oboe are very different from this. But let's take a quick break now. Not all would wind instruments fall into the cab story of open tube physics. Some like the clarinet and the obo are closed tubes. Uh, and obo's and saxophones actually get a little more complicated. They actually fall into conical pipe designation. That's going to get a little too deep

into it. We're gonna stick with closed tubes. So the major difference from a physics perspective on these instruments is how those standing waves form inside the bore of the instrument. So with a flute, we learned that the ends of the instrument are where the antinodes are, where the point of maximum oscillation in regard to air velocity is, and with the node or the equilibrium point inside the boar of the instrument. A closed ended pipe has a node

at the closed end, and this makes sense. It's like the anchor point for a guitar string, like at the nut of the guitar, So the mouthpiece would represent the closed end of the pipe and the node uh would be there with respect to velocity. This also means that the harmonics of a closed pipe system are different from an open pipe system. To really get into all of this would require way more physics and math than worked

well for an audio podcast. But really the important thing to remember is that the nature of the tube of the bore, whether it's open or closed or conical, is going to affect how those standing waves form inside the instrument, and the way the standing waves form affects the different types of overtones the instrument is capable of producing when played, so you get a very different tone out of a clarinet or an oboe than you would with a flute

or recorder. And part of that is because the harmonics that a clarinet or oboe can create are very different because of the nature of those standing waves than the harmonics you get out of a flute or a recorder. I'm sure all that's clear is mud right. Well, if nothing else, remember that the length of the column of air is inversely proportional to the frequency of the sound you produce. The longer the column of air is, the lower the frequency will be, and thus the lower pitch

of note you will produce. And just as we talked about with stringed instruments like the harp or piano, which have strings dedicated to specific notes, there are read instruments that fall into that kind of category too. For example, the harmonica harmonicas have brass reads in them. It's the vibration of those reads that produce the notes you hear when someone plays harmonica, and the lengths of the reads determine the frequency of vibration. A longer read is going

to vibrate more slowly. It's going to take longer for a full oscillation to happen than a shorter read, and so a longer read will produce a lower note. Moreover, harmonicas actually have two plates of reads, so if you were to take harmonica apart, you would find under the top plate you would find a read late. This would be a plate that has typically brass reads mounted on it. The next layer down would be a structure called the comb.

This is a notched structure. It directs the air blown into the harmonica or drawn through the harmonica to the appropriate reads. Below the comb is a second read plate. This is the draw read plate. So blowing into the harmonica activates the top read plate, and drawing air through the harmonica activates the lower red plate. And you have ten holes that you can blow into with your standard harmonica.

So if you choose hole number one and you blow into it, you're gonna get one note as the air is directed to the upper read plate and makes that read vibrate. If you breathe in, you will get a different note because it's going to pull air in and direct it to the lower read plate and it will vibrate that read. Now, typically the draw note is the next one up on the scale from the blown note.

So if the blow note for a whole one in your harmonica is a C. The draw note for a whole one is probably a D. Harmonicas tend to have ten holes, so you get twenty notes. Pretty nifty. Let's move on to talk about brass instruments. So with woodwinds, we're producing vibrations to create those standing waves using either reads or in the case with the flute or the recorder, by using an edge that deflects part of the airstream. But with brass instruments, the source of vibration comes from

something else. It comes from the lips of the person who is playing the instrument. So the player presses their lips against a mouthpiece. The mouthpiece position depends upon the instrument. Some instruments require more of a centered placement, others require more of a two thirds placement. It all depends on

the specific instrument you're looking at. And the player forces air through their lips and they keep enough tension on their lips to create a buzzing vibration, and this is what creates the fluctuating wave of air that goes down the tube of this instrument and ultimately produces the musical note.

The use of the lips has a specific name, and it's the umbature, and it gets pretty complicated, well beyond just the buzzing I described, and it brings into stuff like the tongue and the teeth and the face muscles and everything that's needed to create specific types of buzzing in order to produce specific notes. Because by altering the umbashure, a player can get different notes out of a brass instrument, even if that instrument has no valves or pitch control.

So a bugle, like a typical bugle, is an example of such an instrument. If you look at a bugle, you'll notice that it doesn't have any keys or valves or a slider or anything like that. In fact, you could uncurl a bugle and you would end up with

a really long horn and no controls for it. And you might think that because you have an instrument that you can't change the length of you know, we were talking about with woodwinds that by pressing the keys or by moving your fingers off of holes you shorten that air column. Well, this is an instrument where you can't do that. You can't change the length of the air column in it. So if you can't change the length of the air column in it. How can you change

the frequency? How can you play different notes on an instrument like that? Well, it's done by altering the umberature. By adjusting air flow and tension, players can change the vibrational frequency of their buzzing lips so the bugle will only resonate at specific frequencies those harmonics we've talked about before. So through this alteration and vibration, a bugle player can sound a bugle along a certain sequence of notes the harmonics for that instrument. Typically, bugle plays can get five

different notes. Really good bugle players might be able to get a sixth note, and they're all based on the fundamental frequency of the bugle. Interestingly, the actual fundamental frequency of the bugle itself. The first harmonic is too low for bugle players to play because it would require a lip vibration that's too slow to replicate. So the lowest note a bugle player can aim for is the second harmonic.

If you've listened to my previous episode on the subject, you know that to learn the second harmonic you take the frequency of the first harmonic and you multiply it by two, right, you just it's all whole integers. So This means the second harmonic is the same note as the first harmonic, but it's an octave higher. Most bugle players can play the second, third, fourth, fifth, and sixth harmonics, so five notes, and most bugle calls only consist of

those five notes. Expert players might be able to get out the seventh harmonic as well, for a total of six notes, but it's not easy to do. The specific notes depend upon the bugle, but most bugles I know of are in the key of B flat, and typically it's treated as if it were a C C and B flatter fairly close to each other, so you can

kind of fudget a little bit. Now, all brass instruments use ummature alterations as part of how to produce different notes, but in order to produce even more sounds, people got really clever and inventive, and that's what leads us to instruments that have valves or other methods of pitch alteration. So let's go with valves first and talk about instruments like the trumpet, which I should add was the whole inspiration for me to do this episode in the first place.

Was I sat down and said, how the heck does a trumpet make so many different sounds with just those three keys. Because I'm not a musician, I never went had banned, so I just didn't know how that worked. So if you look at a trumpet, you'll see that it has those three valves. You know, there's three pistons that you can push down, and those valves give the player the same effect as if they can magically change

the length of the trumpet. Each valve, when depressed, opens up a section of tubing for air to flow through. It's adding more sections for air to travel through, thus expanding the length of the air column, and that means the frequency of the vibration of that air column has to decrease because as the length increases, the frequency decreases, and so the pitch goes down. Assuming that the player

is maintaining a stable umbature. Will get to that, and that last part is really important if you play a trumpet in a stable way, so you're not changing the vibrational frequency of your lips as you're playing. You can get seven different notes by using the valves in various combinations. So if you were depressed the second valve the middle one, you would go a half step down from the trumpet

just being played naturally. Pressing the first valve down is one whole step down from the scale, and then you could press them in various combinations to go down another sequence of semi tones. But like the bugle player, the trumpet player can change their umbature and increase or decrease the frequency with which their lips are vibrating and thus

produce higher or lower notes respectively. Then use the valves to in effect change the length of the trumpet and thus play way more notes than you could play if it were like a bugle, and changing the length of the instrument changes the resonant frequency. Remember, the horn is only going to produce sounds at the harmonics in the key for that horn, but pressing down a valve and opening up a new pathway for air to flow through

lengthens the horn, so you change the horns harmonics. It's like the trumpet just grew a few inches, which affects the frequencies it can produce. This is even easier to understand with the troumba. Own Like trumpet players, trombone players can play different notes by changing the umberature, but they can also use the slide on the trombone to physically lengthen the air column inside the instrument. Sliding the slide

out lengthens the overall instrument. Thus it lengthens the overall path for the air to go through, it lowers the frequency or note. Pulling the slide back decreases the length of the path and increases the frequency or pitch. So by changing both umbature and the slide position, a trombone player can play many notes. They can even change their umbature, move the slide out, and play a higher note than the one they had been playing, because again they've changed

the vibrational frequency of their lips. By increasing that vibrational frequency, they're playing a higher note even though they're moving the slide out at around the same time. It's a really complicated thing, and it makes me just respect musicians even more than I already did, because they're like freaking magicians. So it all comes down to how can I use this thing to create sounds that please people using vibrations

in clever ways. That's the basics of all instruments. I'm endlessly impressed with the incredible ingenuity we humans have had in making different musical instruments. To take advantage of these elements of physics that I talked about, and I hope that this episode was interesting to you and that you get a deeper appreciation and understanding of how musical instruments work and how they produce these sounds. There are tons

of amazing videos and articles about musical instruments online. I highly recommend if you want to learn more, to be very specific in what you're searching for. For example, if you want to learn more about how trumpets work or how guitar harmonics work, doing a quick search online is going to pull up tons of resources and give you

a deeper understanding. I consider this more of an overview because, as I said, to really get into it quire a series all on its own, and honestly I should leave that to somebody who has far more expertise than I do. But I hope that you've enjoyed this. If you guys have any suggestions for future episodes of tech Stuff, you can reach out to me on Facebook or Twitter. The handle we use is text stuff HSW, so I will look out for your messages there and I'll talk to

you again really soon. Y. Text Stuff is an I Heart Radio production. For more podcasts from My Heart Radio, visit the I heart Radio app, Apple podcasts, or wherever you listen to your favorite shows.