I understand the difference between RMS and MAX power ratings. Root Mean Square. Don't really know how its value is determined, but do understand that its more important than the MAX rating when trying to match with amplifier power.

I've noticed that the difference between these two values for any given subwoofer can differ greatly. Some subs, for instance, have an RMS of 600Watts, and a MAX of 1200 ( Kicker 10" Solobaric L7). While another has an RMS of 330, but yet a MAX of 1200 (Sony XS-L104P5B). Another has an RMS of 400, and a MAX of 1600 (JBL Power Series P1024).

More often than not, the RMS is usually half of the MAX. Can anything be inferred about the product that has a MAX rating 3 or 4 times higher than the RMS? Is this merely a 'gimmick'? Does it mean that the JBL, in this instance, would be a product of greater or lesser quality compared to the other two? Really, if there was a subwoofer with an RMS of 600, and a MAX of 900, that'd be better than each of these. Wouldn't it?

I'm hoping someone can shed some light on this issue.

 

RMS is more of a rating that coincides with heat build up. Some subs do a better job of keeping the voice coil cool when playing for extended periods.
Peak/max is a rating of what the motor assembly will handle for a short burst.
Overheated voice coils seem to be the number one sub killer.

 

I think (key word here is think) that the attempt is to help the consumer to match an amp (which are rated in RMS wattage) with a woofer (by assigning a RMS value to the woofer). Really a good idea IMO.

The peak number is just that a peak and it could be seconds, milliseconds, or microseconds. Bear in mind this is a 'how big is your *****' rating since every man wants a big woofer that can take jigawatts for bragging rights. Some brands will use misleading techniques to identify the max power rating.