- Learn the five main tone color categories
- Find out the differences between each category
- Which instruments belong to each type
- Also, check out our post on music scales and why we use them
Why is it that we need so many instruments? On the one hand, different instruments have different ranges, but it would only take a few to cover the full range of pitches audible to human ears.
There are multiple sets of instruments in the symphonic orchestra that cover the same pitch ranges. One reason for the preponderance of unique instruments is the importance of tone color to our perception of sound.
So, what is tone color?
Tone color, also known as timbre, refers to the sound profile of an instrument or combination of instruments. Essentially, it is the unique series of overtones that resonate with the fundamentals played on an instrument.
The combination of the fundamental and the overtones shape the sound associated with the instrument and give it its tone color.
Tone color explains why the violin and clarinet, for example, can play the same pitch with similar articulation yet sound completely different. The same could be said for the trumpet and the marimba or any other pair of instruments with some overlap in pitch ranges.
It does not stop at instruments from different families, though: tone color varies between two cellos or two oboes, too, which is part of why instrumentalists grow so attached to their particular instruments.
What Causes Tone Color?
Now that we know what it is, what causes timbral differences in musical instruments? Instruments are distinct from each other in several ways, but an instrument’s tone color is determined by the materials from which it is made and how it is played.
We can attend to these considerations by considering instrument families generally before considering more subtle nuances.
Different Tone Colors
There are five categories into which any instrument around the world can be sorted:
Membranophones are drums. Membranophones cover the range from the snare and other drums of the drum kit to timpani drums, taiko drums, the sogo and kidi of an Ewe drumming ensemble, and any other drum built out of a membrane stretched over some sort of frame or body.
The materials of the body, the membrane, and whatever is used to strike the membrane to produce the sound determine what sort of tone color the drum will have.
Snare drums are not monolithic in sound, of course, as there are a variety of shell materials and drumheads, but the presence of the snares against the snare head results in a particular resonance that sets the tone color of the snare drum apart from another drum, like a tenor drum.
The lower-tension antelope skin membrane of the atsimevu differs markedly in timbre from the high-tension goat skin membrane, as different overtones resonate when striking the two instruments.
Confusingly enough, some instruments with “drum” in the title are not membranophones but are, instead, idiophones.
Idiophones are instruments in which sound is produced when the instrument itself vibrates. The handpan also referred to as a hang drum, is an idiophone, as is its cousin, the steel pan (also referred to as a steel drum).
The xylophone, glockenspiel, and marimba, though laid out like a piano keyboard, are also members of the idiophone family.
These instruments vary in timbre based on the materials from which they are constructed, the type of material with which they are struck, and whether there is a resonator in the instrument’s construction.
The box, gourd, or shell of the kalimba, for example, mellows the timbre of the instrument, which would otherwise have a harsher, metallic sound.
Using a bow on a marimba has a different timbral effect from using soft mallets, and using soft mallets, in turn, has a different timbral effect from using hard mallets. These timbral effects go beyond the obvious differences in dynamic level or amplitude.
Speaking of metallic sound, cymbals are idiophones that produce so many overtones when struck that it is difficult to determine which pitch is the actual fundamental. Tone colors similar to those produced by cymbals are often referred to as “noisy” because of the lack of a clear fundamental pitch.
Chordophones are stringed instruments, whether the plucked strings of a lute, banjo, or guitar or the bowed strings of a cello or viola.
As was the case in the previously mentioned instrument families, the materials out of which the instruments are made play a determining role in the tone color of stringed instruments.
Different types of strings make all the difference in the sound of a guitar, for example, with nylon strings and steel strings having two distinct timbres. The same could be said of the difference in sonority between gut strings and steel wound strings on the violin.
The quality and density of the wood used in making a violin can have legendary effects, as has been the case in the Stradivarius instruments, which some have suggested were constructed out of wood from trees stunted in growth and thus left unusually dense due to the Little Ice Age that occurred between the years 1645 and 1750.
Denser wood is more resonant, absorbing less sound and thus projecting more of it.
Something worth noting when observing timbral differences within an instrument family is that instruments capable of playing lower fundamental pitches typically produce more audible overtones than similar instruments with higher registration.
The cello, for example, produces more overtones with its low C than the viola produces with its low C. A more overtone-heavy sound is often characterized as being “rich,” whereas a sound with less in the way of overtones resonating could be called relatively “thin.”
Aerophones are instruments played with air, such as the woodwinds and brass, but also the organ and harmonica.
The organ poses a fantastic example of differences in tone color, as it is a single aerophone instrument that produces a variety of timbres.
The organist sitting at the console plays the manual keyboards and pedals but also pulls the various stops of the organ that are assigned to particular sets of keys.
These stops are there to control timbre in that they activate particular ranks of pipes and thus lay harmonics on top of the fundamental pitch associated with a key of the keyboard.
Essentially, the organ approximates the different timbres of other aerophones, like particular woodwind and brass instruments, by assigning harmonic overtone patterns to each stop and naming that stop after the instrument in question.
Both in the case of a real oboe and the organ approximating the oboe, a strong fundamental is paired with fairly weak overtones. This sort of sound color is often called “nasal” and can be approximated with the human voice by “singing through one’s nose” in an unsupported voice.
Electrophones are electronic instruments, like synthesizers. The tone color of these instruments is not bound by the materials they are made from but by the electronic manipulations of waveforms that make up the core of their sound properties.
A sine wave is a pure tone, a transparent pitch with no overtones, so it doesn’t have much color.
It is most closely approximated by a tuning fork. Adding another sine wave to the mix, and perhaps a third and a fourth, will create overtones and give the sound more color: this is the concept behind additive synthesis.
Subtractive synthesis is the process of taking a complex waveform and shaping the timbre by manipulating some of the frequencies to either strengthen or neutralize particular overtones.
A musician with both understanding of tone color and one of the more powerful synths on the market today can approximate practically any instrument.
Tone color is an essential part of music, yet music students in their first few years of music theory class rarely, if ever, discuss it. Perhaps this is why it develops something of an intangible, mysterious quality when we discuss it.
The words associated with timbre, like “brassy,” “breathy,” “nasal,” and “rich,” are imprecise and self-referential, but, short of pulling out the spectrogram and pointing to frequencies, we do not have a way of getting any closer to our real meaning.
This is likely yet another byproduct of a system of Western music theory that is obsessed with harmony to the point of ignoring everything else, leaving other musical elements like meter and rhythm behind, never to develop very far beyond the elementary, while in other musical traditions outside of the scope of the Western art music canon, meter, and rhythm blossom.
One thing is certain, musicians who play their instruments or produce their music with an understanding of timbre have an entire palette of musical colors available to them that they would not otherwise have.
Before you go, check out our guide to the 16 Types Of Percussion Instruments!