OK then, there is no such thing as a simple speaker spec.
"Peak" is the largest input you should give a speaker. The reason is that you blow the
like a fuse if you exceed it. or else do mechanical damage.
"RMS" Is a theoretical constant figure. It will overheat if you drive it harder than that for long.
Now, sound is sound so don't listen to anyone who says that the phisics is different for cars.
What REALLY kills drivers is using an under powered amplifier too hard. If you do that you start feeding the driver a distorted (not audibly) signal. Part of that signal is square wave - a cross between music and DC volts. You can't hear DC at all but your
work like heater
Do you really want to listen to a 750W sub? I assume that you have at least a 150W/chan system for the mid/high.
I run a 1400 watt P.A. rig but I never use all of it.
The answer is to buy an amp twice as big as you need (1500W RMS) but never turn it beyond 50%. No one in ICE believes that, but professional sound reinforcement guys treat that as sacred.
P.S. did you know that 750W is only twice as loud as 75W?