before buying the ECM8000s i would check to see if you have phantom power first. Please tell us everything you have already. Also, there is alot of hype about the ECM8000 in these forums. Yes, i agree it is a GREAT low budget mic. But i think people are rushing into buying it a little too fast because of the fact Harvey Gerst recommended it (no im not complaining, thanks a ton Harvey). But there are things to remember about the ECM8000s. First of all, they are omni directional mics, in you case doing mono you probably dont need to worry about it. But if you ever did stereo, be prepared for huge phasing problems. If your room is not a very good room, like a bedroom or something, i wouldnt be surprised if you would actually end up getting a worse sound then if you used a normal SM57 as an overhead. The bad room issue will be a problem whether or not you are doing two stereo or not, because you will be picking up EVERYTHING that is in the room. If the room is not tamed, do not be surprised finding alot of unwanted reflections in the mix. Also, from what i understand, omnis a bit more trickier with placement then cardiod, because of room problems and just the way they work. So if your new to this type of thing, you might have problems finding a good position for the mic in the room.
Im not trying to be all knowing about this, and i might be wrong on a couple of things above. But that is what ive learned to understand about omnis. Yes, i believe they are great mikes for there money, and something you cant go wrong in with buying. But i think just about everyone will admit, that people are buying these mikes just because so and so told them too, and that there is a huge hype about them right now. All im saying, is make sure you consider the other facts along with it besides "Awesome mic for the money." And yes, i own a pair of these myself, and they are great mics for there money, and im glad i bought them.
Just my 2 sentz,
Darnold