I wanted to know if composing music for a specific instrument demands that you know how to at least play the instrument. I'm sure if you know how the instrument sounds by itself as well as within an orchestral setting that's enough. As a composer, should I be learning new instruments I want to compose for or that I will be composing a lot for? I feel like learning how to play an instrument should only be done if you would enjoy playing that instrument regardless of whether you compose for it or not? As a composer, it seems silly to force yourself to learn an instrument just because you think you can get a more intimate feel for the instrument in doing so.
As a composer, you mostly end up writing for instruments that you yourself don't play. Apart from Hindemith, it is fairly impossible to maintain a high level of proficiency on every instrument - there just isn't that much time and it is not feasible.
However, that does not excuse having a working knowledge of the instrument. Though it might seem silly to you, learning the rudiments of each instrument is hugely beneficial to aiding your writing. By physically working with each instrument, you gain insight into things that it does / doesn't do well, sounds it makes / doesn't make, and considerations specific to performers (such as allowing enough time for mute changes or picking up mallets.)
Even if you just squawk your way through Book 1 of each instrument, you will thank yourself many times over for your personal investment. I speak from personal experience. It was easy for me since all of the instrumental pedagogy courses were built into my degree, so by the nature of what I did I ended up learning how to play all of the instruments on a rudimentary level. This knowledge has greatly informed my writing - not only writing idiomatically but also with phrasing, texture, and orchestration as well.
It is perfectly acceptable to write music for an instrument that you don't know how to play - all that matters is that you know how to write intelligently for the instrument, how the instrument behaves, and how to make it sound good. It is instantly apparent when a composer does not know how to write for a given instrument, and all that does is make the composer look very novice - since they in fact are.
It is not enough to understand how an instrument functions soloistically or within an orchestra - it is also paramount to understand how that instrument functions in chamber settings, in choral settings, and with different families of instruments. I would write for two clarinets very differently than I would write for clarinet and trombone duet.
As a composer, you have nothing to lose by learning how to play an instrument - if for no other reason than doing so will help make you an informed composer and therefore make your music better. Wouldn't you want to write better music?
That said, I realize that it is not always feasible to do so (though it is quite affordable to rent an instrument for a month or two with a method book.) But in addition to learning what you can, I would highly suggest studying texts on orchestration. Walter Piston, Alfred Blatter, and Samuel Adler have all put out excellent texts on the subject. In addition, I would also highly, highly recommend that you talk to people who play the instruments for which you're writing. They've already put in all of the time learning the instrument and can offer invaluable insight. You can have them play through sketches and determine what works / what doesn't work. In addition, it serves as a great resource for networking, which is crucial for getting things performed.
For composers, getting things performed is the bottom line.
Hope that helps.
jjmusicnotes' answer is a good answer, and I'd like to make a special plea for the percussion section. I know many musicians don't have much time for percussionists, but as a composer the section can be your ally. It can keep the ensemble together (whether there's a conductor or not); it can give you a lot of support for dynamic changes; and it can help make tempo or time signature changes easier.
As a percussionist, I've often been given a part that makes no musical sense, or even one that isn't physically possible to play. Even good arrangers often fall into the trap of guessing what percussion instruments and style might give the sound they want, instead of indicating what sound they want and letting the player work out how best to achieve it. This is crucial outside of a pro orchestra context, because different groups will have different equipment available: there's no standard percussion section.
It's really easy for even an inexperienced player to spot a part that was written by someone with no percussion experience. You don't need to learn every percussion instrument to get it right, just speak with percussionists (in whatever ensemble you're composing for) and get them to show you a good part and a bad part.
First thing I literally HAVE to say: Learning an instrument you're writing for is not just for emotional/spiritual/warm-fuzzy-feeling reasons ("eg I have learned to play flute and now my flute and I are one, wandering the earth as band geek ascetics" [I do not play flute; that was just an example]) --there are many practical and educational reasons behind doing so. Not only does knowledge of the instrument you're writing for enable you to write higher-quality, more cohesive parts that can be played with less effort, the more ensemble settings you play in and the more well-rounded you become as a musician, the better you will be as a composer overall. (hopefully that made sense) And I have to ask: If learning a new instrument sounds so "silly" to you...what instrument do you play? (just wondering)
I have done arrangements (as in arrangements of songs) that involved instruments I didn't know. In many cases, learning the instrument just to be able to write for it is impractical, depending on the skill level of the target audience. Some situations and examples that come to mind, either from my own personal experience or just my general knowledge:
- My knowledge of playing piano helps me write music (when I write a song on piano, I usually pick out the voicing that is best for piano as I develop it on the instrument rather than in notation software or on another instrument) for piano, as well as create playable arrangements (my rule of thumb: If I can't even slowly work my way through it, it's probably not playable [this helps me avoid adding passages that involve the player stretching across four octaves with their left hand]).
However, it was not plausible for me to learn viola to the extent of my friend's skill level when arranging a piece that involved viola parts. In this case, using my own abilities to measure the part's playability would not have been accurate (he was very very good).
- Concert F is a great key for band, but not for orchestra. For choir? I have no idea.
- In that same line of thought, my choir friends often complain about the unsingability of my vocal parts ("I have no room to breathe", "That's a bad note for that syllable", "This spans too wide a range"). These very legitimate issues likely result from the fact that because I don't sing, I think like a French horn player, a guitarist, a drummer, and a pianist, but not like a singer.
- I don't play organ. I don't know the typical ways of coordinating multiple keyboards, the stops, etc., and the foot-keyboard in practical ways that would "make sense" to an organist. Therefore, I write organ parts for songs and just have the computer (Finale FTW) "play" it on the recording, but don't ask real organists to play them for me. Then, it is okay for me to just go by ear without having to worry about practicality.
- I imagine it would be difficult to write guitar parts without knowing how to play guitar; I suppose you could try to map out the notes on a fretboard diagram, etc. to check playability (this becomes more of an issue the more notes you have played at the same time). Some of the coolest guitar licks can be played easily because they stay within three frets (on multiple strings, of course). Certain intervals that sound like they'd be difficult to reach are therefore not, because the guitar has more than one string. Also, complicated picking patterns are much, much easier if they involve open strings.
- I play guitar, but I have no clue where to start with bass parts. I know there are standard bass licks and patterns, but I never take the time to look for them. Fortunately, I also (almost) never write bass parts.
- The key of G is excellent on guitar, and I've found that I can easily play five- and six-note chords in the key of E (and it's just by moving a few simple chordshapes up and down the neck). However, E and G are terrible on French horn, particularly because concert B natural is really out of tune in band in general, and so is concert E. G and D are good keys for orchestra (or so I've been told; I avoid writing for string instruments because I get complaints about fingerability). Most pianists seem to prefer the key of C, though this is most likely because they don't like to worry about sharps or flats. (This isn't a problem for me, so I tend to improv in E, B, F, and D. But I'm weird.)
- Instrument ranges are a very big deal...especially when you write for beginners or even intermediates. (You should never write outside of the range of the instrument itself [eg C0 for a flute, or C10 for a contrabassoon], where even the best in the world wouldn't be able to play].)...and it doesn't always work the way you might think. I almost caused a disaster when I assumed that lower notes were easier on trumpets' chops [embouchure], which is how it is on French horn, and gave the third trumpets the lowest part, and the first trumpets the highest (which wasn't too high most of the time). My trumpet friend quickly corrected me and I swapped them -on trumpet, playing in the lower register is the quickest way to kill your face. On woodwinds, embouchure isn't as much of a problem, but range definitely is more standardized per skill level (eg "Freshman saxes should be able to play from this note to this note comfortably for long periods of time" is a much more reasonable assumption than "Freshman trombones should be able to..."). I use Finale's range checking system to tell me (unobtrusively) when I write things that are out of range for the target skill level. Pianists' range isn't so much an issue as reach is.
- When writing for marimba you should take a few things into consideration (and I don't play marimba myself!):
1) Yes, they can play blisteringly fast, and yes, a typical competent marimba player (this excludes middle school-level) can use four mallets at once (in addition to the normal one mallet per hand, of course), but they still can't play more than four notes at a time!
2) There are four-octave marimbas (common) and there are five-octave marimbas (not-so-common). Typical Marimba note ranges? I don't remember. But I had to know at one point.
3) Many marching bands' marimbas (in the pit/front ensemble) also have cymbals attached. Also, they usually listen back to the band and drumline for tempo. Write accordingly. (Obviously, don't worry about that for solo marimba pieces.) Don't forget that different mallets can be used for a different sound.
- Certain patterns of finger combinations are easy to play quickly, and others are nearly impossible. (ex 3 2 1 3 2 1 vs 12 2 1 23 3)
- On winds, certain notes are trillable and others are not. This differs instrument-by-instrument.
- Wind players and vocalists need to breathe (circular breathing is rare) --phrase accordingly. Ensembles can work out issues, though, by "stagger breathing"; soloists cannot.
In the event that you do need/decide to write for an instrument you don't play [as others have said more concisely]:
- Find someone to play the part for you. (What else would you do with it?)
- Look at (as in really look at, and perhaps try to visualize yourself fingering through passages if possible, if you play a somewhat related instrument [eg guitarist writing ukulele part, hornist writing baritone part]) things written for the instrument by seasoned composers/arrangers.
- Ask a friend or random stranger who plays the instrument to look it over. Also ask for guidelines (eg "Hey, what should we expect the incoming freshman tenor saxes' comfortable range to be?", "What's the basic framework for a pop/rock drum groove again?"). Google should be considered a friend, but random stranger works just as well.
- Trial and error works (eventually) --see if the target can play the piece. If not, fix it! (Yes, you must ask for feedback --one way to start is "Hey, I realize that this was kind of a fail. (WHY DO YOU HATE ME?) What should I change to make it work?")
- Yup --you should definitely research the instrument. (If you're writing for steel drums, you should decide what kind of steel drums they are, and determine what kind of part that kind typically plays; if you're writing a concert band piece you should (at least!) know which instruments have the melody, the countermelody, and the bassline/sustain parts.
- Type it into notation software (such as MuseScore [recommended free software], Finale [what I use], or Sibelius) and see what it sounds like. If that trumpet wailing up in "the stratosphere"/its very upper register is not what you intended for the soft, delicate passage, then rewrite it. Things that look pretty on paper do not always enrapture listeners. Follow your ears!
- Try to apply what you know. I can basically write a feasible score for band, because I play a brass instrument (I can apply my knowledge to the other brass instruments easily; it's no coincidence that we mess around on each others' horns and sound decent), and I hear enough about woodwinds in band class (eg "Clarinets, you have to support that lower register to bring it out", "Stay in tune when you play the high E, flutes"), and I play drum set and observe percussion and drumline and can therefore write decent parts for both sections. I also know that clarinets, flutes, and trumpets often have similar parts or the melody, and that alto saxes and French horns often have very very similar parts, as do baritones and French horns in other situations. I've learned that tubas have downbeats and French horns take the upbeats in traditional marches. (If you're not in band and you want to write for band, I'd recommend listening to a lot of concert band pieces and watching a lot of marching band shows to get these instrumentation patterns down.) My experience in band helps me basically none with orchestra and choir, so I do the things on this second list when I have to do write for them.
That's about all I've got; the other replies cover the bases pretty decently. I wanted to put in my five billion bits though (I can never stop at just two). Happy composing!
You don't have to learn to play the instrument, but you should definately learn about the instrument and it's possibilities and limitations!
If you don't learn about the instrument you run the risk of
- writing music that is technically unnecessarily difficult, or impossible, to play. For example: making bad keys selections; writing note sequences that require crazy fingering combinations; failing to recognize physical limitations such as finger stretch or breath needs; etc.
- writing music in ranges that doesn't sound good or doesn't allow playing as soft or as loud as you wished for. For example: the lowest saxophone notes might be tough to play soft; the throat register of a clarinet shouldn't be expected to be very loud; etc.
- missing out on possibilities that the instrument offers. For example: different pedalings; alternate fingerings; double stops; easily accessible arpeggios; different timbre production techniques; mutes; harmonics; fast octaves; glissandos; etc
To learn about an instrument's possibilities and limitations you could for instance
- study books on the topic, such as books on composing, arranging, and/or orchestration.
- search and query sources on the internet (including music.SE :-)
- talk to musicians proficient on the instrument
- take classes or lessons on the topic
- read scores for, or including, the instrument - preferably while listening to performances of these - to see what seems to be common usage of the instrument and to discover usage ideas that you didn't know about.