jasone said:
2x10 cabinet
each speaker = 200 watts / 8 ohms
Wired in parallel brings ohms to 4
What would the watt rating be for the pair?
I've been told two different things:
1. Watt rating does not change - 200 watts
2. Watt rating is sum - 400 watts Thanks,
Keep in mind that a speaker's watt rating [unlike a lightbulb or an appliance] is not "what it draws" but what it can handle. So it won't change.
How you get that 200 watts to the speaker doesn't change a thing. If your head puts out 200W at 8ohm, then one 8ohm cab will allow the the head to output 200W. If your head delivers 200W at 4ohm, then it will only output about 140W at 8ohm, to that same cab, or any other 8ohm cab.
Now, if you parallel 2 such 8ohm cabs, you get a 4ohm speaker network. Whatever your head delivers at 4ohm, that will be split evenly to the speakers if they are identical. A head that outputs 400w at 4ohm [typically 280W at 8ohm] can deliver 400W to 4ohm network, which amounts to 200W per cab using that pair of identical 8ohm cabs. If a head delivers only 200W at 4ohm, you have only 100W per cab, but since you have 2 cabs running at 100W each, you do still have 200W of output from your rig.
Audiences do not hear watts. Just because the total output wattage is the same with [for instance] a single 12" 4ohm cab or a pair of 12" 8ohm cabs [= a 4ohm 2x12 network] doesn't mean the loudness is the same for the audience for both options, even though total output in each option is 200W.
Then, there's the possible situation where both 8ohm cabs are not identical. You can NOT assume that when you parallel 2 differing 8ohm cabs into a 4ohm network that each cab will get an equal share of the "4ohm rated output wattage" from the head. With such odd couplings, if it sounds good, it *is* good, unless it smells bad and gets hot. Then, it is *not* good.
