Do you notice the different sounds produced by a single note that you pluck on your guitar as it vibrates through the air? The sounds you are hearing are the overtones. What are overtones in music?
Technically speaking, any frequency greater than the primary frequency of a certain sound is called an overtone. Another way of putting it is overtones are higher pitches produced by the lowest or fundamental note. Usually, the fundamental note is the sound you hear prominently, but its overtones are always there.
Overtones are also considered harmonics. They occur when the high points of two sound waves overlap each other at certain intervals. Additionally, the overtone is a general term referring to any higher-frequency standing wave. Overtones are also sometimes called harmonics or resonances.
Read on to learn more about overtones, their nature and how they are defined in music, and other details about them that will enable you to understand them better.
What Are Overtones in Music?
A Frequency Greater than the Sound’s Basic Frequency
You can refer to any frequency greater than the basic frequency of a sound as an overtone. Meaning, the lowest or most basic note produces higher pitched overtones. You always hear the fundamental note, but you don’t notice the overtones very much, but they are there.
Applied to Any Standing Wave with a Higher Frequency
Commonly, the term overtone refers to any standing wave with a higher frequency. Also, overtones are similar to harmonics or resonances. They are actual sounds that accompany the main tone coming out from a body that vibrates.
Both the Human Voice and Instruments Have Overtones
The human voice has overtones as well as musical instruments that produce sounds of music. For instance, when you pluck a stretched guitar string or violin string, it will vibrate in several different ways at that same time. As a whole, its many vibrations will produce the lowest tone.
An Overtone Is a Harmonic
So, an overtone is a harmonic that forms due to the overlap between the high points of two sound waves at certain intervals. For example, the octave above any given note is always twice the frequency of that note. So, the high points in the lower note will overlap with the high points of the higher note every other time.
Highest Normal Mode Frequency
A majority of oscillators, such as a flute being blown, or a guitar being plucked or strummed, will naturally vibrate in their normal modes, which are a series of distinct frequencies. The fundamental frequency is the lowest frequency in this normal mode, while the highest normal mode frequency refers to an overtone.
When you pluck a guitar string, it oscillates at some of its modal frequencies simultaneously. This thing always happens when you excite an oscillator. So, when you play a note on the guitar string, you will get the sensation of hearing other frequencies or overtones way above the fundamental note or the note’s lowest frequency.
A Practical Explanation of Overtones
A practical explanation should help you understand what overtones are. If you play a note on a musical instrument such as the guitar or the piano, or if you sing a note, other notes will also vibrate in sympathy with the note being played.
The note that you are playing or singing is called the fundamental. No matter what kind of note you are playing or singing, there is always that fundamental. So, if you are playing or singing the C note, the first thing that vibrates is the strongest in the upper octave.
After that, the second strongest thing that will vibrate is a fifth above that upper octave. The third strongest will be the octave above the fifth. Then the third will come in. You will now have a full chord. These three notes compose a chord, and it is usually called a major chord.
Some say they are not a chord. They believe that that’s just how sound works and that they are built into the nature of sound. In other words, that’s how sound vibrates. It’s not because someone decided they have to do it that way.
Overtones Occur Naturally
That is just the way sound was created. Overtones naturally occur. They are not the product of a musician or musicians deciding; they have to produce overtones. Overtones can sometimes be faint. When they are faint, you can hardly hear them.
Usually Experienced by Musicians
A lot of musicians usually experience overtones. For example, there will be a quartet, say four guys singing a tune, A Cappella. Suddenly a certain sound appears. But not anyone from the four guys is singing that sound. They may be startled and ask: “Who is singing that?”
Well, nobody is. It is just the overtones coming out of the voices and floating in the air as the quartet sings. As a matter of interest, people who are not very good at pitching notes are not likely to hear the overtones. But if you are pitch accurate, you are more likely to produce and hear clean overtones.
Accurate and Perfect Pitches Produce Overtones
When you listen to a group of singers singing A Cappella, and they have accurate and perfect pitches, you will often hear the overtones above them. You might be wondering who is singing that part. Actually, no one is. That’s just the produced overtones because of the very accurate pitches or notes that they are singing.
Again, what are overtones in music? An overtone is a musical term that refers to a harmonic partial other than a fundamental or an inharmonic partial. Moreover, a harmonic frequency refers to a fundamental frequency’s integer multiple.
Overtones Define the Timber of a Certain Sound
There is another aspect that relates to overtones. As I already explained, an overtone is any frequency greater than the fundamental frequency of a certain sound. This means an overtone is the highest pitch that usually comes out from the fundamental or lowest note.
Overtone Partials Identify a Specific Sound
The relative amplitude or volume of the different overtone partials is one element that identifies the individual character of a sound. In the language of music, this refers to the timbre.
Timbre is the quality or definition of a sound. As such, it gives you the ability to distinguish or identify the sounds of different instruments. The overtones that a musical instrument emphasizes determine its timbre.
Intensity of an Overtone Is Not Constant
In other words, the relative volumes or amplitudes of the instrument’s overtones to one another determines its specific ‘tone,’ ‘color,’ or ‘flavor.’ What is interesting for you to note is that the intensity of every overtone is not always constant during the playing of a note. Given time, different overtones may decay or fall off at different rates.
This condition causes the relative intensity of the individual overtones to rise or fall. It happens with each individual note. This is the reason why you may perceive the timbre of a note in different ways when it is played legato or staccato.
If you carefully train your ears to hear overtones, you will be able to hear these subtle changes even if you are focused on just one note.
Two Types of Overtones
An overtone is also a partial wave that could be a ‘constituent frequency’ or a ‘partial wave.’ From here, we can branch out to the two types of overtones. The two types of overtones are the harmonic partial (other than the fundamental) and the inharmonic partial:
The harmonic partial has partials with frequencies that are numerical integer multiples of the fundamental (including the fundamental, which is one multiplied by itself).
The inharmonic partial has partials with frequencies that are not whole-number ratios of the fundamental, such as 1.2 or 2.15268.
You will notice the overlapping terms. They are used when the acoustic behavior of musical instruments is discussed. This definition is just a simplified method of describing overtones, but they can fairly explain the sounds of musical instruments.
In reality, overtones and harmonics are two different things. Overtone has a broader meaning since it is any higher frequency that is above the fundamental and is produced at the same time.
For a frequency to be considered harmonic, there is an additional condition required. A harmonic is any higher frequency above the fundamental and an integer multiple of the basic, fundamental frequency.
That would put overtone as an umbrella term. We already know the two kinds of overtones. Another way of describing these two overtone types is:
- Harmonic overtones – the integer multiples of the basic, fundamental frequency, and
- Disharmonic overtones – the overtones that are not integer multiples of the basic, fundamental frequency.
The overtones of a majority of musical instruments only deviate slightly from their true harmonic frequencies. So, their overtones can be considered harmonic frequencies since their overtones are close enough to each other.
Their higher frequencies may not be precisely double than their fundamental frequencies or even three times, but they are very close.
Additional Information About Overtones
Overtones Are Upper Partials
To help you better understand what overtones is, allow me to give you additional information about them. You already know that overtones are harmonics. Another way of putting it is that they are upper partials. In reality, they are extra or additional notes produced when a musician plays a fundamental note.
Fundamental Note Is the Loudest Sound When You Play a Guitar String
When you play a guitar string, the loudest sound you will hear is fundamental. It is the note you will sing back if you would and the note you can easily identify. This note or sound has other notes or sounds that you can also perceive, to a greater or lesser degree.
Let’s focus our attention on these other sounds or notes. The first sound is an octave above the fundamental. It is followed by a perfect fifth above that first sound or note. Then it is followed by two octaves above the original or fundamental. After that, the extra harmonics follow at smaller and smaller intervals. They are usually quieter as they proceed.
Every Instrument Has a Mixture of Upper Partials
Every musical instrument has a mixture of different upper partials. This is the reason for the uniqueness of the tone or timbre of each instrument. One of the instruments that are rich in overtones is the violin.
Learn the Sensation of Overtones by Playing a Guitar
If you want to get a sensation of overtones, get a guitar. If you will touch and do not fret a string while plucking it, you will hear its overtones or harmonics. Touch a string 1/2 of its length, and it will produce the first octave.
Then touch the string about 1/3 of its length, and it will produce an octave and a fifth. Touch it 1/4 of its length, and it will give you the next octave. Do this carefully along the different lengths of the string, and it will give you different overtones or harmonics.
Conclusion: What Are Overtones in Music?
In technical terms, any frequency greater than the basic frequency of a certain sound refers to an overtone. Another explanation of overtones is that they are higher pitches that the lowest or fundamental note can produce.
In general, the sound that you hear prominently is the fundamental note. It is the sound or pitch that you can identify easily. But the overtones of this basic note are always present. Some people believe that it’s the natural way of sound creation.