So can you describe how coated Emperors would differ from clear Emperors on an 18x16 floor tom? I just got one with my new kit and I've only had one go at tuning it (clear Emp). I couldn't get a great sound out of it and found it really hard to tune.
A coated Emp has a slightly warmer tone...a little more controlled sound, not
as open (but it does have an open sound if you don't use any muffling--I don't) and the attack on the clear head seems brighter.
The clear heads can sound really fat and deep, but the coated's have that bit of controlled crispness that I like, and they get plenty fat sounding too.
I actually think that a coated Ambassador on T&B can get a beefier sound than an Emp/Amb combo--but what you use is up to you.
On an 18" floor tom, it's a good idea to listen to the drum standing
over it, and away from it, have someone else hit it (as well as sitting next to it) etc... because you'd be surprised at what it sounds like after the sound has that little bit to develop.
When you are right there sitting next to it, it might sound a little flat, or not like what you think you want to hear, but listen to it at a different angle or place and listen to what it really sounds like.
An 18 is a big drum, and it can get tricky because you might want to hear this big, fat solid sound (big and fat, but cuts off--like on a cd), but it might sound kinda ringy, or not as fat or whatever, but you have to listen and adjust a little as needed.
It can sound big, fat and solid, but it might sound like that where the mic is, and where someone is sitting a little away from it, and not exactly where your ear is sitting at the kit.
Since the 18 FT has a lower note to begin with, if it doesn't have much resonance orprojection, it's not going to translate over a PA either, so if you are getting mic'ed up at a show, make sure your drum(s) has(have) some life to it (and is tuned well) if you want people to actually hear it well.
A
little muffling like half a moon gel or a rolled up small piece of tape can get a more solid tone out of it too, just be careful of overdoing it because it can start to sound slappy and the tone can get hollow.
Good luck, I hope some of this helps.