I have never blown a speaker using the amp 10% over speaker method. The key is not to go over 3/4 volume. If that isn't enough power go with more power. As for a complete system I use the 1-2-3 method. Highs 1X, Mids 2X and Bass 3X power (50, 100, 150 watts) This is for sound quality(SQ) and not for the db race setup. And for the sake of your speakers DO NOT crank the input level to full max. There is a detent that the manufacturer setups up for the best signal to noise(s/n) ratio for the cleanest sound(too low you get hiss and too high you get distortion). That produces more distortion and clipping. But as usual everyone has different opinons. Heck I have seen a method that is a wattage per inch of cone(1" tweets 10 watts, 6 1/5" 65 watts and 10" 100 watts). I don't claim to be any kid of expert, but in my job in the Air Force I work with satellite microwave amps ranging in power from 3 to 15,000 watts, and I have seen the 2 high/2 low signal level in action using test equipement.

 

in short

The amp will try to meet the power demand placed upon it, but it cannot exceed its design capabilities. This in turn, produces the deadly "square wave" output to the speaker. The speaker sees this severely clipped signal as something similar to DC current. Speakers cannot deal well with DC inputs. The cone goes in or out and stays there. No motivation to cool the voice coil and sooner or later, the speaker will fail.


Kinda half right - yes the amp starts putting out a "square wave" because it has run out of energy but it is not seen as a DC signal by the speaker. For two reasons, first DC in both the positive and negative axis would cancel at the speaker, your square wave is centered on the zero time axis right? If that were not true then what has happend to the OTHER HALF of the square wave or original sine wave for that matter - what is rectifying the signal? The signal normally goes both positive and negative from the zero axis - your speaker normally moves IN AND OUT doesn't it? Out represents the POSITIVE lobe and in represents the NEGATIVE lobe of the sine wave - (or square wave). And in the case of a sine wave you get a nice vibrating tone, the cone moves in and out following the sine wave. So how do you suddenly only get "OUT" or "in". In "lay-z-boy recliner" logic, if your speaker only moves out and stays there when the amp starts clipping how do you still get any sound from a now motionless speaker cone? Every amp that I've heard in clipping makes a racket. Second all amps have DC blocking on their outputs. So to figure out what is happening you have to convert from "time" to "frequency" and to "make" a square wave in the frequency domain requires every frequency there is. I know this is beyond them, but in short you start with a sine wave of the same frquency as the square wave and add lots of smaller, higher frequency sine waves to form those nice sharp corners. Suffice it to say all of that high frequency energy is what blows out the speakers, tweeters first simply because they are not designed to handle it. And how can an amp in clipping that has "run out of energy" now blow out a tweeter? Simple - because it is now producing lots more unheard high frequences to form that square wave, frequencies you can't hear but the tweeter has to deal with. And if it can't move that fast it just converts it to heat (not DC but AC that it can't deal with) and eventually overheats and fails. That's why a lower power amp in clipping (say at 25 watts) will burn out a tweeter but a higher power amp at the same power output (25 watts) will not. Again - the low power amp is dumping garbage into the tweeters while the high power amp is making a real clean signal you can hear.

 

You are absolutly right about the "DC" output of the amp. I just cut & pasted from the website that the link referenced. I guess I should have proofed it. I was in a rush and just threw it up there. I'm glad someone is paying attention haha