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Harvey Gerst
 
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Default Audio amp 40 watts, loudspeaker 19 watts; How to adapt?

Nousaine wrote:
stuff deleted
I sometimes challange the Legend with what I call the "Underpowering Contra
Argument". If "underpowering" with a small amplifier were the true cause of
speaker damage then driving one with the output from your preamplifier or from
the headphone jack on a walkman should be avoided at all cost.


Okay, let's look at this problem slightly differently and see if it makes more
sense.

When a small amp goes into heavy clipping it produces a signal that looks pretty
much like a square wave. Forget about the harmonic train for a moment and just
look at (or consider) the shape of the signal: a sudden rise to the top, it
stays there for a while, then a sudden drop to the bottom, where it stays for a
while, and then it repeats all over again.

There's another way to describe that kind of signal: pulsating DC. For a
speaker, it's a hard signal to handle. The speaker moves out and simply sits
there, then it moves in, and sits there. While it's just sitting there, being
held out (or in) by the voltage, the temperature in the voice coil is rising,
since there's no way to dissipate the heat from the "DC" that's holding the
speaker still. Do that long enough (even at lower than maximum speaker ratings)
and the coil will eventually burn up.

Is that easier to grasp?
Harvey Gerst
Indian Trail Recording Studio
http://www.ITRstudio.com/