Dumb Quest : Amp Clips Or Speakers Blow Up First?


I was reading in another thread somewhere here on Bryston amps that go into clipping when driven hard. How do we know if the speakers can take it when we crank up the volume to earth-shattering levels? In most cases, distortion will kill the drivers of the speakers when listening to insane levels but how do we know if the amp will clip first, or the speakers will blow up first? Do we need any measuring tools or device to measure on how loud can the system go before something burns?

And what does clipping mean? I am guessing the amp will shut down itself. Will the amp blow up into flames of fire? What is normally replaced inside the amp when it has clipped? My amp never clips before so maybe I'm not cranking up the volume loud enough. Most of the time my ears fail first before my equipment do, so it is unlikely I will experience any amps clipping or worse, the speakers blowing up. That's a real nightmare if my speakers would blow up.
ryder

Showing 2 responses by shadorne

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.
Fatparrot,

Thanks - you were right to correct me. Indeed, it would be more accurate to say "deliberately compressed" than "deliberately clipped". Not so many are actually hard clipped. The majority of modern pop CD's are "soft limited", which clips the peaks in a rounded fashion (meaning that the peaks above a certain level are limited in a gentle manner in order to reduce the dynamic range).

However, excessive compression due to "soft limiting" or hard clipping will tend to sound the same anyway....harsh, loud and distorted at the end of the day excessive soft limiting becomes the shape of a squared of sine wave too.