Ryan Y. wrote to ask about words for "the sounds instruments make". He points out that in English, "Drums go 'rat-a-tat' and 'bang,' bells go 'ding dong,' and sad trombones go 'wah wah'", but he notes that there are some gaps that he finds surprising:
Few instruments are as popular in the US as the guitar, but I have no idea what sound a guitar makes. There are gaps even for the standard high school band/orchestra instruments. What sound does a violin make? A flute? For that matter, what sound does an orchestra make? A rock group?
Is there a compelling explanation as to why we have words for the sounds of bells, trombones, and tubas, but not guitars? Why do we lack words for the sounds of groups of instruments? Do, say, Italians have a word for the sound a violin makes? Do the French have a word for the sound of a French Horn?
It seems to me that the situation in English instrumental onomatopeia is a bit more diffuse than Ryan suggests. A web search for "went the fiddlers" reveals that fiddlers have often been considered to go "fiddle fiddle dee fiddle dee", or perhaps "tweedle dum, tweedle dee", or maybe "twee tweedle dee tweedle dee", Similar searches reveal that harpers go "twingle twangle", pipers go "ha-diddle, how-diddle" or perhaps "tootle tootle too", flutes go "toodle-oodle-oo", or maybe "Too-too, too-tum-too, tooty-tum", or just plain "toot toot".
As for guitars, they go "twang", don't they? And theremins go "woo" (perhaps the origin of the term as used for dubious science). Certain kinds of rock bands go "unn-tss unn-tss" or "unce unce". And let's not forget "oom pah pah".
We can also find less obvious things like "Bum-bum-bum went the guitars and tambourine in unison".
Still, I think that Ryan is right, the English inventory of instrument-imitation words is a bit sparse, and rarely includes ways of imitating ensembles. I'll leave it to commenters to tell us about the situation in other languages.
(I don't think that we've covered this topic before — though there have been some discussions of differences across languages in onomatopeia and ideophones, e.g. "'Ho ho ho', she laughed in a refined feminine way", 7/21/2004; "Hot features", 8/24/2004; "Unh, Ka-BOOM, BZZURKK", 7/21/2004; "Phonics", 12/30/2006; "Ask Language Log: Sounds and Meanings", 3/9/2008; "Waza waza", 3/20/2008; "Japanese (and Chinese) onomatopeia", 7/21/2008; "Unce", 5/22/2010; "Wait Till You Hear a Weak Pyridaben Carbazole Sound", 6/30/2010.
As for those French and their horns, Wikipedia explains that
When valves were invented [in the 19th century] the French made smaller horns with piston valves and the Germans made larger horns with rotary valves. It is the German horn that is erroneously referred to in the English language (and more commonly in the United States and Canada) as the French horn.