I'm adding rears to my setup. I have Focal 165s in front which are rated 120W max, 60W nominal. My JL 300/4 is rated at 75W per channel of course. I haven't settled on which speakers to use for the rears yet.

Should I be looking at more power or will the Focals be happy with 75 each?

 

JL amps are rated in rms (nominal) power, this amp will provide more then enough power for those speakers

 

Ignore max power for just about any audio related decision. That is the wattage rating at which the units fail (they test them in lab conditions, and turn up the wattage until the speakers finally blow or the amp fries). Pretty much useless. Look at nominal or RMS wattage ratings. These are even kinda shady with some companies measure watts with different tools and methods. There was a standard enacted at the consumes electronics show. I think its CEA-2006. It standardized the measurement procedures for a watt. Companies that have complied can be directly compared easily, but boot-leg brands claim haigh wattage ratings, but almost never deliver.

So to answer your question, look at RMS values.

john

 

Werd... stay with the JL. Adjust the gain on your amp to 85%-ish and you'll be set. The amp will never over-push the speakers and should last forever at that power output level.

 

i tend to disagree with the match the power thing. i always go with way more power than ratings.

first thing, most people never get the rated power from the amplfier. the more power the more dynamic and louder it gets without distortion. more importantly, much more solid midbass.

i had 400 watts total driving my front stage only. this was measured by the way.

personally, i feel that amplifiers sound different when they are under different loads. imaging, staging and tonality characteristics change a bit. given the fact that the gain is adjusted higher, the amplfier will sound different. i feel there is a sweet spot with adjusting the amplfier. usually, never turned more than 65% of the way. depends on the amplifier of course. i usually set my gains with an o-scope and i usually work with high end amplifiers so my experience with lower end equipment is limited. what if its not loud enough when the gain is adjusted 65% or less? get a more powerful amplifier, louder with lower gain setting.

some may disagree with me, but this is my personal take on things and it has worked well for me and a lot of people i know.

 

with most of that statement. I do not like to kill my amps either. I will be running a 125wrms amp to the front stage, but it will be set to around 80-90wrms. The rear will be on a 110wrms amp, but I will lower it to around 50-60wrms (to save the speakers).

Do you mean this by tuning or power availability? Some amps are WAY underrated (like Alpine) usually. Pikkashoe got an MRV-F545 RATED at 125wrms, but was bench tested at 179wrms. That is almost a 50% increase.

Either way, it pays in the long run to have a good tune done.

John