Originally Posted by AcuDefTechGuy
Speaking of debunking, there is a myth that real life music presents a more difficult load and stress to the amp than in the lab where pure test tones are feeding the amps. They argue that just because the amp measures well into 4 ohms or 2 ohms does not mean they can handle real life music the same way. This is wrong. The reason is because in the lab, the pure test tones at keep at a constant impedance. So a constant continuous 2 ohms impedance is a heck of a lot more stressful to the amp than in real life music where the impedance varies from 2 ohms to 20 ohms.
For AVRs, the RMS continuous 4 ohms testing is a lot more stressful to the AVR than real music playing on speakers that vary impedance from 4 ohms - 20 ohms.
So we have debunked 2 audio myths:
1. Amp clipping does not damage speakers. Speakers are damaged due to thermal and mechanical causes secondary to excessive power, not due to any clipping.
2. Amp testing in the lab is a lot more strenuous and stressful to the amp than playing any real life music.
I suppose these are debunked so long as evidence to the contrary is ignored.
1. There are FFT measurements of amps with moderate clipping changing the tonal balance so as the shift the power distribution toward the upper frequencies.
What has been shown is that amount of energy added from the square-waves is not as likely to damage as the compression and power shift.
So, it is not that a lower power amps is more likely to damage speakers, it is that those inclined to overdrive an moderately powered amp can drive their tweeters with more power than they can handle and cause the thermal problem.
Tweeters do fail an the vast majority of users do not have separate power amps. There is no evidence that a separate power amp is required for tweeter to fail.
To believe this is a myth (presented as an absolute) is to believe that tweeter failure is a myth.
2. Not all amp testing is the same and not all AVR amplifiers are tested with the same rigor as their standalone counterparts.
Testing in a lab can be more strenuous than testing in a lab, except when it is not. For example, for speakers that dip below 4 ohms.
If heat is an issue, the duration of a 4 ohm test matters as well. A few minutes may not be indicative of a 4 ohm speaker listening for an extended period of time.
Here is a real world example. I was able to put the A51 (on an open shelf) into thermal overload driving my Revels with musical content at near reference levels (-5 or so).
The amp has been thoroughly tested into 4 ohm loads 20-20kHz and the Salons are specs are 6 ohms nominal.
Does that make them bunked