Thanks Dash - think I'm a little clearer now! It just started to get confusing reading posts about connecting however many speakers to however many channels! I just want to connect 1 PSR15 speaker to each channel and wanted to know what amp to buy to run them without having to worry too much about under/over powering and ending up with rubbish sound!!
So much easier with actives!! haha!
QUOTE(dj_dash @ Apr 24 2012, 11:06 AM)

Right. So.
A channel is one output from the amp - most amps have two channels, typically one for the left signal and one for the right signal. There's not much more to channels than that.
The output per channel is what power you'll get from each. So your 2 x 400w = 2 channels, each producing 400w each, at 8 ohms.
You'll find that, at 4 ohms, they'll have a higher power rating, because there's less resistance. The lower the resistance/impedance on the channel, the more power it will drive.
(Although keep in mind that some think that double the resistance means half the power - it doesn't!! Always see what the manufacturer's ratings are for each impedance!)
So to answer your question - yes, an amp at 2 x 400w @ 8 ohms will do for driving your PSR-15s. :-)