Miata Mailing List: April 1995, Message #6
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   From: Soundbld@aol.com
Subject: Re: SPEAKERS ...
   Date: Sat, 1 Apr 1995 12:10:04 -0500

With all due respect, I must dissagree with you. An underpowered amplifier
can definitely "blow" a speaker.  When an amplifier runs out of power we say
it is "clipping". This means the maximum ouput level at the speaker wires is
equal to the amplfier's power supply voltage. What this means is the amp no
longer is reproducing AC signals (music) it starts to become a DC generator.
The music's peaks are cutoff and the signal starts to resemble a square wave.
Because the amp is no longer reproducing peaks, there is no longer a cooling
down period for the speaker's voice-coil. This causes overheating and
possible failure. A 50 watt amplifier can easily blow a speaker rated for 100
watts. To use a 200 watt amplifier with a 150 watt rated speaker is not
asking for trouble. On the contrary, provided the user is not going to clip
the amp, it is better to have a overpowered amplfier. In high output testing
on one of our small studio monitors, we have driven a speaker rated for 100
watts with 1600! watts of peak program material. There was absolutely no
problem. This was with a very dynamic live digital recording where the ratio
of average power to peak power was quite high. The point is, as long as an
amp is not clipping or the speaker is not being mechanically overdriven
(bottoming), speakers can be used with larger amps than suggested by the
speaker's rating. This is a very common mis-understanding. Using an amplifier
with a rating of 50 watts with a 100 watt speaker does not necessarily mean
the sound will be  "quiet/poor quality". This has nothing to do with power
rating. This has to do with many variables, background noise level, speaker
sensitivity, cone area to room volume ratio and simply how loud you wish to
listen. For most listeners in a quiet home, background level music only
requires a 5 watt per channel amplifier. Because sound power is a squared
function, we need much larger amplifers to achieve a small increase in sound
level. If one thinks they need a larger amplifier, you must upgrade your amp
to one with at least 2X the power. It is probably best to upgrade by a factor
of 3-4X. Sorry to go into such detail but I want to be sure the information
on the Net is correct. I think you meant well, it is just some people may
mis-understand your comments.
Taylor