How much does it take to learn how to play the triangle?
How much does it take to know how to play the triangle?
Hundreds of hours of practice, years of experience.
Just like many "simple" activities (such as taking a photo), while the concept is simple (just push the button on your camera), it takes knowledge and experience to get it right - or, better, to not get it wrong.
The problem with the triangle is that is a little devil:
- it has a very precise percussive sound, so it's much more clear if it's played out of time;
- it can be clearly heard, even when struck softly, and even when the full orchestra is playing;
- it's small and it's easy to miss it if you don't control it very well (professional percussionists have dozens of different tools, pliers, claws, forks that they choose according to the situation) - and, let's say it: if you have been sit for 30 minutes, then you finally stand up just for a single "ping" and you miss it, everybody will laugh at you;
As other have pointed out, if you're playing in a non professional orchestra/band, nobody would tell you that "you cannot play it" - and in many amateur groups is common to have a "non skilled musician" play percussions ("they do less damage" - but we know that's not always true).
Doing it in a professional situation is a completely different thing.
You have to learn how to choose the instrument and learn how it behaves (no triangle is the same), choose the appropriate beaters and learn different techniques in order to provide the good result - no matter if less than 1% of the audience would realize the difference. Most importantly, precise control is the hardest thing: you have a range of few millimeters that separate very different sounds and dynamics - or decide if you're actually playing or missing.
Finally, consider that while a "simple" triangle usually comes at less than 15$, professional triangles have a price of over 100$, a professional percussionist usually has more of them, and a set of beaters can cost between 50$ and 100$. A non percussionist certainly wouldn't be aware of the value of such tools, nor she/he would be able to make any difference of them.
Some have rightfully pointed out that the choice of a good instrument or even its price are not the matter at hand. Yes, it's true, as much as you don't normally need a degree in Medicine to say that you're ill.
That wasn't my point: saying that there are professional instruments that cost a lot and/or are normally chosen by professionals doesn't mean that "cheap" instruments (or players that use them) are of no value.
But the fact that most professional players mostly use professional instruments, even when dealing with a simple instrument like that, is important. It's not about being "picky", or "we all [professionals] do that": the point is that it's a very peculiar instrument that, due to its nature, many would underestimate its value and usage.
Knowing that there are billion-worth cars doesn't mean that you can't drive any, or that you must be a billionaire in order to tell that they could drive well any car (we all know that's not true).
Knowing how cars and driving work is the point.
You can still look like (and be) an idiot even while driving a billion worth car and crashing it, as much as you would while playing a 200$ worth triangle, if you don't know how to play with it.