I have a alpine M500 amplifier running a hifonics
Hmmm, let me see here. Did you mean to say you have TWO subs connected to this amp? A single sub can only be wired in series with the amp. Even if you have a capacitor wires in parallel, the capacitor is not a load, but a souce equivilant, and therefore can be merged with the amp as a single source when put on paper.
When they say a sub or amp is so many watts rms, that means that the device can function safely, without worry of failure. THERE IS NO LEGAL METHOD FOR DETERMINING THIS NUMBER AND NO REGULATIONS ON VARIANCES. Having said that, if an amp is 500w rms, it could very well push double that for long enough to blow your speaker. It all depends on how much power went through that speaker. So since you have a 4 ohm speaker, not two, and it would actually act like a two ohm speaker if you put another one in parallel because 4||4=2ohms equivilant. never never never, turn the bass all the way up if your gonna beat loud. Low frequencies draw lots of power and can damage your system.
you can tell if your speaker is blown by turning the volume to a medium listening level and placing your hand on the cone. you will hear a crackling sound if it is blown
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