What is the etiquette for phones & ringtones in an office?

I would not start with an email. You're the new person, so it could come off as "here are my preferences and I'm going to enforce them on the group". I would start with whomever you feel closest to and ask if this issue has been raised in the past. Maybe informally, and verbally, see if anyone else is bothered by it. You can frame it as "at my other offices we were all instructed to set our phones to vibrate, so I'm not used to this, what do you think?" My husband once worked in an office where anyone whose phone rang out loud had to bring in doughnuts for everyone else, which is a fun way of changing habits.

Surely this is something that should come from the office manager. especially as the 'new person' it is not your place to change an established office environment is it? Raise it with the office manager (or your boss) and ask them politely if there is some way that a guideline for ringer volume in the office could be considered. It's not up to you to dictate how the office should be, but it is up to you to raise productivity concerns for yourself with your manager.

This bothers me, too, but it has helped to remember that in most offices, people's desk phones are ringing with a similar tone, and it's just part of being in an office.

Talk to the person who runs the co-working space and see if they will write the email/add a "put phones on vibrate" rule to the group policies. This should come from the person collecting the rent for the desks, not you.

I think what you're experiencing is that your colleagues came of age as workers when there were no cell phones--just desk phones, ringing that "old phone" ring all day long. It's something most people who worked in an office learn to tune out very quickly. So in their minds, those are their office phones and totally appropriate background noise in an office environment. As someone on the younger end of that age range, I actually find musical ring tones tremendously distracting but have no difficulty ignoring the classic ring. I guess you could bring it up, but I'd be prepared to not get very far.

Do you agree to any sort of rules when you take on a space there? Anything about noise, perfume, whatever? If not, you don't really have any grounds to force them to put their phones on vibrate just because it's what you're used to -- I would definitely not put up a sign, because they'll just figure out you put it up and wonder why you think you get to set policy. (It's also basically an empty threat -- you're putting up a sign when all it really is is you personally wanting it the way you want it.) I'm not disagreeing with you on the substance -- I hate excessive noise also, but if you're the new person in this space, you're going to have a hard time telling them they've been doing it all wrong, and I would definitely not do anything that even suggests for a moment that you think that because they're in their 40s and 50s, they don't know how to put their phones on vibrate or "haven't experienced" everything that you have. It's likely just office culture, and one could just as easily say that because you're young, you haven't ever experienced a noisy workplace, which doesn't make having a noisy workplace incorrect. In other words, my preference would be the same as your preference, but if the standard practice in a space you just arrived at is to do it differently and there's no central person who can mitigate disputes, you may be out of luck in enforcing your (our) preference.

http://store.apple.com/us/question/answers/iphone/is-there-a-led-notification-light-in-front-in-iphone-5/Q2U7PUFPHKP4U47XY

I don't think it's unreasonable at all and wish more people would speak out against noise pollution, everyone is so used to it now... I once worked with a guy I really liked socially who had his horrendous, intensely irritating radio on all day (so selfish and antisocial unless everyone was into it, which they weren't). I eventually made myself bring it up in the office. The good/surprising news was 3 people backed me up. The bad news was that it didn't change a thing. I then considered escalating it, but couldn't face it and didn't want to fall out with the bloke. Good luck. I'm with ya.

There are no office managers or bosses, just a bunch of freelancers. It's deliberately set up without any real hierarchy, just a co-shared space. I don't work in a coworking space, but I've spent a fair bit of time in them. As you've noted, there's no heirarchy - it's all just consensus and shared culture. The reality is that this is a space in which regular loud phone rings are accepted and normal. Some coworking spaces have a culture of avoiding phone calls in public areas; others don't. This is pure culture, and if you're the outlier who doesn't like it - and especially if you're new - I think this might just be a sign that you should keep looking for a new space to work in.