In Western music there are four classifications of instruments strings, woodwinds, brass, and percussion. This classification works on most instruments, but there are many different instruments around the world and some cannot be put into these groups. Two common examples of this are a piano and an accordion. Is there an alternative way to classify instruments that can be used to classify all insturments?
A Google search on "musical instrument taxonomy" yielded a reasonable picture with the key feature:
Thus the top-level division is between
Note that this method of division lumps brass and woodwinds into the same top-level category.
Note, there are other ways to slice this pie too, c.f. Wikipedia article on Musical Instrument Classification.
To expand on Dave's answer, this system is called the Hornbostel-Sachs system. According to wikipedia, it is "the most widely used system for classifying musical instruments by ethnomusicologists." It works similarly to the Dewey decimal system, using a series of digits to classify each type of instruments (every group of three digits is separated by a period). The first digit corresponds to the instrument families that Dave (and jjmusicnoters) listed:
Under each of these top-level categories is a further series of subclassifications that is better described by other references, such as the wikipedia page. One example they give is a valveless bugle, which is classified as 423.121.22, which means that it is an aerophone whose vibrating air is contained within itself and set vibrating by the player's lips, which also provide the only means of pitch control; furthermore, that it is tubular, end-blown, folded, and has a mouthpiece.
trying to categorize sounds is a total nightmare !!
there are 3 main ways I've come across:
So for classical acoustic instruments, there's the mouthpiece type, general material used to make the instrument, how percussive it is. This is a pretty mixed bag, because you can make a sound with ANYTHING AT ALL. Not just the usual acoustic instruments in an orchestra
Then you can categorize a sound by lead (foreground melody sound) versus bass (sound for the chord root - pretty low, and noticeable in that it's "felt") versus chords (not as noticeable, but usually pretty rich and long lasting sometimes termed "pad")
And then you can go with characteristics of the sound wave itself (bright for high frequencies in a narrow spectrum; muddy for lots of frequencies all over the place that can interfere with existing sounds if you're not careful; grating as in a sawtooth wave; mellow as in a sin wave; there are tons of characteristics of sounds you'll eventually become familiar with).
So it gets VERY messy VERY fast.
What I tend to do is keep sounds in directories that AREn't very well defined.
I'll have a drum dir for percussion; piano, organ, lead for percussive lead sounds; guitar, strings, acoustic dirs for the chords sounds; The general midi standard's 8 sound groups are a pretty good way to sort your sounds:
Piano, Organ, SynLead, SynPad, SynFX, (leads)
Guitar, SoloStr, Ensemble, (chords)
Brass, Reed, Pipe, Ethnic, (classical acoustic-ish)
Bass, (for the chord root/bass)
Perc, ChromPerc, SndFX (weirdly pitched)
Drum: Kick, Snar, HHat, Cymb, Toms, Latn, Misc
If you keep your sounds in dirs like those, it'll be easier when you try to map your sounds to a new synth. And that's a VERY big deal.
This may not work for you. But that's what I do.
I believe that electronic instruments deserve 2 separate categories, and distinct from electrophones (which make sound by manipulating an electrical arc or field AKA the Theremin):
1.) Digital instruments. Sound is a representation of digital signals produced by a digital computing device.
2.) Analog electronic instruments. Sound is produced by manipulating an alternating current.
I also think that it might be possible to divide instruments into categories based on how they are used, ie keyboards, bowed strings, plucked strings, keyed woodwinds, etc.
Just to add yet one more alternative system, Olivier Messiaen has divided the percussion section into animal, vegetable and mineral.
Animal: bass drum, snare drum and timpani with calfskin heads.
Vegetable: Xylophone, made of wood.
Mineral: Bells, cymbals.