Okay, maybe we need to go into a little more detail.
Basic theory - you need to
play in time with whatever is being triggered off the laptop, be that loops, samples, or
synths, etc. So the drummer will need to be listening to a click. This will not be able to
go through speakers (or the audience will hear it) and so the drummer will have to wear
headphones of some description. It doesn't have to be specific/expensive IEM, it can just
be standard enclosed/closed back headphones, or standard shop bought in-ears, and you just
need something to act as the headphone amp, say a small mixer, or a dedicated headphone
Now this doesn't mean the drummer cannot have a wedge as well. What he can
do is have the click in the headphones, only wear one ear of the headphones, and have the
wedge for the rest of his monitoring. I generally advise against this as it can lead to
some quite high volumes in the headphones and wedge, and this can lead to hearing loss.
So what you then need to do is have a feed from the laptop with the click which
goes to a mixer next to the drummer. The same mixer has a feed from the PA mixer aux that
would usually server the drum wedge monitor. Instead of going to the speaker it will go to
the mixer next to the drummer, and the drummer can then mix in enough click so he can keep
in time, and hear the rest of the band through headphones alone.
that it just comes down to rehearsing so that all the samples fall in the right place if
you're playing to a backing track. I've heard many click tracks, and some have voice
counts so that the drummer knows when to start, and if there are any key moments to make
him aware of.
Hope that explains it a bit better
course, ask any more questions if you're unsure!
Music Teacher, Isle of Man