max ratings only mean whats the absolute maximum power that can be put into the speaker, eg a huge amount of power/sound for a couple of milli seconds. it really has no huge meaning.
nominal ratings mean this speaker can take XW of power for an indefinate amount of time. this implies a flat un-changing signal or sound (as we hear it) and is again not an exact replication of exactly how much power a speaker can handle.
both max and rms ratings are not perfect but rms is FAR better because it introduces a standardised platform to test speakers on.
now if you were wanting to know what the exact amount of power your speakers can handle, no one can tell you that. music is all onver the place, with so many sounds with in sounds, if you will, that to be able to say my speaker can handle 80Wrms doesn't mean much because the power could change from 60Wrms to 100Wrms as the song and different notes are played.
so pretty much its not about how much power your speaker says it can take, there are so many other differences between speakers, such as excursion, cone material, magnet material, basket material, spyder material and construction, the list goes on. always remember that the sound level only increase just noticably when the power to a speaker doubles!
ok as for the whole impediance thing with subs, think of a huge pump going down to 1 tiny tap that only lets out a litre per sec of water. the water is the amount of power that the pump (amp) can deliver. the tap (sub) is the resistance or imediance in the whole circuit. so if you had 2 taps you could pump 2 times as much water as compared to only 1 tap, providing the pump can supply the water.
so taking that a sub with 4 ohms of impediance will only let through so much power. but if there is 2 subs coming off the same amp terminals then 2 times the power can be supplied by the amp. so now the two 4 ohm subs have a total impediance of 2 ohms (eg 4ohms/2subs=2ohms). so pretty much as long as the amp can keep supplying power you can keep adding subs.
thats PARALLEL wiring.
now if parallel havles the impediance, series wiring will double.
series is where the subs are connected one after the other. so two 4 ohm subs in series will have a total impediance of 8 ohms. therefore the power that can be supplied by the amp is about halved.
now the small problem with parallel is that an amp will only supply so much power before it will heat up so much its breaks. so pretty much most amps will go down to about 2 ohms total impediance. some amps such as the jaycar monoblock (specifically designed to make the most power possible, so its good for subs.) can power a 1 ohm load.
now some subs have only 1 VOICE COIL others 2. all this means is at you can wire the subs differently to get maximum power. so if you had 2 voice coils with 4 ohms impediance and wired them in parallel then there would be a total impediance of 2ohms (4ohms/2 vioce coils= 2 ohms total impediance).
now if they were in series the it would be 8 ohms (4ohmsx2voice coils=8 ohms).
ok i am tired, bed now and if you have any questions then post them and i (will be on tomorrow night) or someone else will answer.
. I found the website pretty good with the Wiring Wizard when I first started fiddling with subs a few years ago.
