I just got a new yamaha DTXpress 2 (woohoo!!) electronic drumset, brought it halfway around the world (they dont sell those in Vietnam) got it lost by french people....(im going somewhere with this) and today I finally get it delivered to me, all battered of course.  

So I spend 2 hours setting it up and plugging everything in, and when Im ready to turn it on i realize I have no earphones or amps to use. So I just sat there banging on it silently for a while  

Anyways, Im looking to buy new earphones, the ones that completely cover the ears, and some time ago i was reading a post about them, which of course, now that i need it, is nowhere to be found. I remember people saying something about it having a certain number somethings to protect your hearing or something like that.  

So i just wanted suggestions on cheap but good earphones (anywhere under $20) AND/OR specifications they should have.

Thanks in advanced...

I have no suggestion for under $20 for sure. As a radio guy I use Sony MDR-V700's. I also have a pair of MDR-V6's that are "ok" but the 700's run circles around them! Cheap? Heck no! The 700's are about $150. The 600's can be had for about $80. I use a set of "in ears" on stage that cost about $20 but they're about to be put aside for some professional model E1's. I don't recommend leaving your hearing to cheap headphones! The 700's I mentioned are very true in their frequency response and will be perfect for what you described. I've used my 700's many times live. Looks funny, but sounds great!

Sony MDR CD380
These work well with E-drums and they arent too expensive. You can find them for well under 50 dollars. Look on Ebay as well. Good Luck!