Dumb Quest : Amp Clips Or Speakers Blow Up First?

Speakers blow first....but a blown speaker may in turn then damage an amplifier!

Clipping is when the amp cannot follow the proper waveform (voltage) due to exceedingly high current demands and the output will flat top. It is unlikley to damage your amplifier (at least initially) but can easily damage a speaker...usually the smallest driver, the tweeter, blows first as the coils get too hot with the distorted squared off signal.

Clippiing results in all kinds of non linear distortion that is audible but can easily be confused with or perceived as "loudness" (call this "perceptive loudness"). Your observation that "ears fail first before my equipment does" may be a sign that the music is clipping and has dramatically increased your "perceptive loudness" (since your B&W and PMC speakers are both near field monitors that are unlikley to be able to play very loud).

The "perceptive loudness" effect is what is often used on modern pop CD's, whereby the waveforms are deliberately clipped in the recording/mastering process in order to create a "loud" sounding CD; the distortion makes the "perceptive loudness" much higher (even at low actual loudness levels).

The "perceptive loudness" effect is what makes most consumers feel that there Hi-Fi system plays extremely loud when in reality it does not (it just begins distorting at some point and thereafter is perceived as extremely loud).

A really good recording (uncompressed) on an excellent system (large dynamic range without clipping = large headroom) can be played extremely loud and still sound pleasant to the ears.....you may have experienced this at a concert where live music levels are thrilling and exhilarating and you can hear such incredible detail. (even an unamplified piano has a huge dynamic range, well exceeding that of most consumer audio)

Bob Katz at digital domain has an honor roll of CD's that are not compressed and hence have a very low "perceptive loudness" and can therefore be played at extremely loud actual SPL's without sounding "perceptively loud".

"Actual Loudness" and "Perceived Loudness" and their relation to distortion/clipping is quite misunderstood even by most audiophiles.

Great post, Shadorne. This issue is one reason why its hard to duplicate actual live music levels at home; it just dounds like crap and your ears beg for mercy unless as you put it, you have a rare uncompressed recording and a system that can reproduce those dynamic peaks.

Shadorne, a slight correction regarding your statement

The "perceptive loudness" effect is what is often used on modern pop CD's, whereby the waveforms are deliberately clipped in the recording/mastering process in order to create a "loud" sounding CD

In fact, I believe that these CD's are compressed, so that the dynamic range may be as little as 6 dB's, so that it sounds "louder"...this is a common trick for TV commercials. Limiters would be used to actually "clip" a very dynamic waveform, but are used more for radio broadcasting than recording.

Thanks for all responses. Shadorne, actually what I meant by the line 'when my ears fail first' is that my ears cannot take the sound pressure anymore although I can still crank up the volume. The music is already very loud and if I turn up the volume further it's not the equipment or speakers that would blow first but my ear drums would! This is due to the fact that my listening room is quite small, and if I were to place the system in a larger room I am sure I can still turn up the volume higher with/without going into clipping.

I would agree that nearfield monitors can't play too loud as they have their limitations in their design. However, I find the PMC's are able to go louder and deeper without showing any distortion whereas the N805's seem to lose it a bit. THe PMC's can really go loud and still stay clean at complex musical passages, and although I was tempted to test it to the limits, my ears tell me to stop due to room limitations. Got to be the transmission line thing. I highly doubt it's due to 'perceptive loudness' in my case.

Let me pass on an experience I had regarding McIntosh amps. I hooked up a MAC 602, which is 600wpc, to a couple of little Cambridge bookshelf speakers and cranked it up just to see if their Power Guard and Sentry Monitor technology would work... and it worked perfectly.