Which classical stringed musical instrument should I learn to eventually join an amateur string quartet?
There are never enough violists, especially among adults. IMHO (I am a trombone player, and my knowledge of strings comes from a quarter of “string techniques for music teachers”, so take this with a grain of salt), the viola has a remarkable sound when played well, and if you get into later Romantic quartets (i.e. out of Haydn, Bach, early Mozart), you get to play some really cool parts (Dvorak string quartets tend to have wonderful viola parts). Other advantages: it’s bigger than a violin, and a hell of a lot easier to play in the early stages. I don’t know how big you are, but I’m 6’5″ with big huge trombone player hands and I had a hard time with the smaller fingerboard on the violin. The viola is more comfortable. There are also of course the cello and the bass – double bass is a hell of an instrument but you wouldn’t be able to play in most small string groups (i.e. quartets). The cello seems to be a load of fun but my experience with it is zero, so I’ll leave that to someone els
If by “equally interested” you mean you’re equally able to afford any of them, you’re in a great position to focus on cello, which I personally find most exciting in terms of sound… but rossination and others are right that viola is most in demand. The order of need/demand among adult amateurs is viola most needed, then cello, then violin (even though there are two vns in a string quartet, there are definitely more than two amateur violinists for every violist). In any case, please don’t buy the cheapest instrument you can find (ebay is glutted with barely playable string instruments that seem cheap but will cost more than their original price to adjust/maintain — a good “student quality” instrument will cost a little more but absolutely be worth it).
