Driving the cab or head too hard?

[jelwood]

So I have a question. Forgive me if it has been asked before, but I found nothing with the search function.

Let's say that I have a head and a cabinet to match. I start driving the head more and more until I finally start hearing an audible distortion. My question is, how would I know if I've hit my cabinet's limits or if my head just simply won't put out any more? I've heard talk about people saying that some speakers are more efficient than others, and that their speakers themselves sometimes reach their maximum performance before their head does. So, how do we know when this is going on?

As an example, lets say that we paired a 500 watt cabinet with a 600 watt output head. Now, anyone in their right mind would either avoid this scenario or not drive their head very much, but let's just be a little insane here and do it anyways.

Case 1: So the cabinet would max out before the head, and we might hear changes in our sound to accompany this.

Case 2: But, say we paired an 800 watt cabinet with the same 500 watt head. Now the head maxes out before the cabinet. Again, we might hear associated distortion.

So basically I'm curious as to the differences in distorted sound in case 1 vs. case 2. Does anyone have any idea at all as to how they may differ?

I guess this is a good thing to know because if you find yourself not being able to get loud enough without farting out, you can make the decision as to wether your amp or cab needs the boot. Particularly if the wattage rating on your head and cab are say, within 50 watts of each other.

Now, I KNOW you're supposed to have a cab that has a wattage rating a good amount greater than what you're head can put out. But for the sake of argument, consider what I'm saying.

Thanks!

[Jaco who?]

The watt rating for cabinets has nothing to do with it's max power handling before it "farts out", it's only a thermal wattage rating for when the voice coils get too hot. Most cabs handle anywhere from 1/3 or maybe 1/2 of the thermal rating before you should begin to hear it reach it's xmax, or maximum excursion. If you ignore the beginning of the papery "pfttt pfttt pfttt" noise, (usually on lower notes) you'l reach xlim(it) and blow the speakers.

Amp distortion is a whole other thing, usually sounds the same regardless of the note you play.

[RickenBoogie]

Yup, you can't nail down the matching of amps and cabs. Some pairings work well, others don't. Doesn't really matter what the RMS rating is on either piece.