I've used an AGA ffm at the Aquarium, to do the shows there. The communications feature enables us to do our dives while talking to the audience... And a "bone conduction device" similar to a Buddy Phone (but placed against the skull rather than on the ears) allows the diver to hear what is going on outside the tank. Thus, the diver can communicate with the Aquarium's patrons.
It's a pretty neat setup, but there's some issues which don't come up until you've used one of these ffm's. Those of you who use them will know this, but in case someone's reading this that hasn't used one of these is curious about ffm's, there's some things that you should know...
Firstly, talking underwater, even at our Aquarium's 41' max depth is very strange. Sure, a regulator is designed to deliver air pressure that's equal to your surrounding pressure... So talking shouldn't be funny. However, the air that's running past your vocal chords is simply more dense than it is at the surface, and so it just feels funny. I don't know how to describe it. Sure, you can communicate, but it takes some getting used to. It's not like you can just strap one of these things on and *poof* you're golden.
Secondly, everyone thinks that being able to talk underwater is a great thing. I can tell you from using communicators on motorcycles, in scuba equipment, and even CB or FM radio vehicle-to-vehicle, that communication isn't always desired. After using it a while, you often wish you could just go back to your quiet little world. I can see how it'd be useful in a commercial application, and it's certainly a bonus at the Aquarium. However, I don't think I'd want to use one on a regular basis.
Thirdly, ffm's seal around your face... Of course, this means that your face isn't wet and using one feels very much like walking in space... But imagine how strange it is to have an ooa in a full-face mask. You breathe in, and not only do you not get any air, but this thing on your face actually sucks in onto your face, locking on as you try to inhale. It takes a bit more than just spitting out your reg and getting a buddy's reg or alternate air source... It's much more serious. Imagine... Typically, there's like five straps holding this thing on your head, and at least in the AGA's case, you've got to loosen a strap first to get the mask off. It can complicate things really fast. This is why everyone's recommending the training. Simply put, ffm's are missing the simplistic design of a regular mask and reg.
Lastly, I don't know of any "real" ffm (one that is singular in design and has an open oral/nasal cavity) that does not use acrylic as the "window" of the mask. Acrylic, unlike glass, is not relatively scratch-resistant. Quite a bit of care must be taken to keep the viewing surface clean and nice... And if you scratch it, we're not talking about replacement for $50, you know? We're talking about a pretty serious investment here. And no matter how you treat the mask, it's still going to get beat up a little. You can take great care, and it'll last longer, but it's never going to last like a standard mask does.
Don't get me wrong... FFM's definitely have their place. In fact, I'll be using one when I do my World Record Dive this spring. They're great for communication and to prevent jaw fatigue.
But don't forget that there's a reason why most don't use them unless they're particularly called for.
Having said all of that, does anyone know of a ffm that's really a ffm (as in, not the "cheater" Scubapro style) that uses tempered glass rather than acrylic? I hate that stuff.
