"MZ" pam
wrote:



I agree with all of the above. In fact, it can be advantageous to
have an amp that is rated higher in power than the rating on the
speakers. I've seen a 40 watt amp fry a pair of speakers rated at
100 watts each due to significant abuse of the system (they were
trying to use it in a hall much larger than they should have).

That's what you get when you assume power ratings to accurately reflect true
power handling capabilities.

This is true. Tweeters generally have a modest power handling capability. But
the Urban Legend about small amplifiers being dangerous to speakers is chronic
and widespread.

A few years ago at a PSACS meeting a speaker technician from an Illinois
retailer gave a talk about speaker damage and repair. When asked if small
amplifiers were dangerous to tweeters he emphatically said "oh yes" and
produced a discolored voice coil (from a small woofer) and declared that this
damage came from using a small amplifier.

Because the coil looked like several others he had shown earlier I asked how he
knew that that had been the case. He said that he knew the owner of that
speaker and had watched him "abuse that speaker with that little amp ... for
years" completely ignoring the possibility that the guy might have blown up
that speaker in much less time with a bigger amplifier.

I'm of the thought that the urban legend of small amplifiers and tweeter damage
is simply a retail technqiue to sell amplifiers when some one brings in a
damaged speaker. Because the most likely speaker damage is a blown tweeter the
Legend gets to be used most often for that situation.

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.

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.


An interesting response but perhaps a little anticdotal. The
shortest job that I ever had was once I was hired to be a
bricklayer's helper. I was healthy, but not a really strong guy.
I was strong enough to lift buckets of morter and concrete but
after a short while I would get a little shakey. I spilled some
concrete once or twice on a wall because of my lack of strength.
If they had hired a stronger guy, it wouldn't have happened. If
they had hired a 3 year old kid, it ALSO wouldn't have happened
since the kid wouldn't have had the strength to even lift the
bucket in the first place. To say that the damage I caused was
not due to my lack of strength/control and say the proof is that
someone with even less strengh wouldn't cause any damage seems to
ignores some key elements of logic somewhere :-)

The problem is where there is enough power to get things going
but not enough to control things well. If my boss missed the
issue and somehow thought I could do twice as much work, he might
of made me carry two buckets at a time (like the other "Charles
Atlas" helper he had). Since I COULD lift two buckets, you might
say I could do it, but I suspect that there would have been twice
as much damage.

The issue with the speaker ratings is that they never tell you
how the rated power can be safely distributed across the spectrum
of the speaker or how they even arrived at the rating in the
first place. A "50 watt" speaker may only be rated for 1/4 watt
across the 5KHz to 20KHz band. As has been pointed out before, a
speaker rating is not linear across its entire bandwidth.

There may be some standards for speaker power rating but I don't
think that I've ever come across one.

- Jeff

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/

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?

Unfortunately, it doesn't really clarify anything. In fact, it muddies
things up even more. First of all, there's not really such a thing as
"pulsating DC". That's an oxymoron. If it's "pulsating", it's by
definition an AC signal.

The rest of what you say would be true only if the fundamental was on the
order of fractions of a Hz. It's a nice idea, but it's simply not the way
it works. The voice coil doesn't care a whole lot about the motion
waveform - it just cares that motion is occurring. Whether it's a square
wave or a sine wave, it makes no difference. Also, due to the inductance of
the voice coil and the limitations of the amplifier, most speakers will
generally not move in a square wave fashion anyway, even when the amplifier
is severely clipped.

"MZ" wrote in message

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?

Unfortunately, it doesn't really clarify anything. In fact, it
muddies things up even more. First of all, there's not really such a
thing as "pulsating DC". That's an oxymoron. If it's "pulsating",
it's by definition an AC signal.

Your skepticism is IMO well-founded.

When you cleanly clip a music waveform, it doesn't just look like a square
wave, it is a variable-frequency square wave. However, there's no guarantee
that a true POS power amp will clip cleanly. What this comes down to is that
a POS is a POS, and using a POS power amp can be dangerous to your system,
no matter what its power rating is.

If we drop the POS power amps from the discussion, we're left with what
happens with a competent low power amp as opposed to what happens to a
competent high powered amp.

To understand this better, you have to consider how speakers fail. IME the
most common form of driver failure is caused by overheating of the voice
coil. Second is fracturing of the voice coil wiring due to excess flexing. A
third failure mode relates to over-travel of the cone. These three most
common loudspeaker driver failure modes have a common cause - too much
power.

Much has been written about spectral shifting due to clipping, and this can
clearly stimulate the first and second modes of failure by causing more
power to be routed to high frequency drivers.

However, there's a lot of music around whose high frequency spectral
content actually decreases when it is cleanly clipped, and even more where
there are no appreciable changes.

Classical music is one genre where upward spectral shifting can still be
dominant, but even there it's not a sure thing. During crescendos crashing
cymbals and blaring horns can build up a lot of power at high frequencies.

The bottom line is that most of the failure modes of drivers come from the
driver receiving too much power, too long. The easiest way to get more power
to a speaker is to have a more powerful amplifier. These days, 100 wpc power
amps are unbelievably inexpensive. 100 wpc is a lot of power for most
consumer speakers to handle, long term.

Intensely powerful *accidents* are more likely with more powerful
amplifiers.

More powerful amplifiers also provide a psychoacoustic cause for speaker
damage. Undistorted music often sounds less loud than distorted music with
equal power. Therefore, a listener is more likely to apply more power to his
speakers with a more powerful amplifier. In the absence of clipping, the
music will not sound as loud as it will if it is clipped.

That all said, I have just a few kilowatts of power amps around the house,
and most of them are hooked to speakers. The good news for my speakers is
that I have a lot of fairly robust speakers, and I try to be careful.

I don't think there is any doubt that over the past 30 years loudspeakers
have become as a rule, more robust.

More powerful amplifiers also provide a psychoacoustic cause for speaker
damage. Undistorted music often sounds less loud than distorted music
with
equal power. Therefore, a listener is more likely to apply more power to
his
speakers with a more powerful amplifier. In the absence of clipping, the
music will not sound as loud as it will if it is clipped.

This is an excellent point, and one that I had overlooked in the context of
this discussion.

"MZ" wrote in message

More powerful amplifiers also provide a psychoacoustic cause for
speaker damage. Undistorted music often sounds less loud than
distorted music with equal power. Therefore, a listener is more
likely to apply more power to his speakers with a more powerful
amplifier. In the absence of clipping, the music will not sound as
loud as it will if it is clipped.

This is an excellent point, and one that I had overlooked in the
context of this discussion.

While were're on a psychological, social, and behavioral mood, let's
consider the effect of blood alcohol on driver connectivity. Alcohol is a
general nervous system depressant, and the ears are hooked to the brain via
the nervous system...

"MZ" wrote in message

More powerful amplifiers also provide a psychoacoustic cause for
speaker damage. Undistorted music often sounds less loud than
distorted music with equal power. Therefore, a listener is more
likely to apply more power to his speakers with a more powerful
amplifier. In the absence of clipping, the music will not sound as
loud as it will if it is clipped.

This is an excellent point, and one that I had overlooked in the
context of this discussion.

While were're on a psychological, social, and behavioral mood, let's
consider the effect of blood alcohol on driver connectivity. Alcohol is a
general nervous system depressant, and the ears are hooked to the brain via
the nervous system...

"MZ" wrote in message

More powerful amplifiers also provide a psychoacoustic cause for
speaker damage. Undistorted music often sounds less loud than
distorted music with equal power. Therefore, a listener is more
likely to apply more power to his speakers with a more powerful
amplifier. In the absence of clipping, the music will not sound as
loud as it will if it is clipped.

This is an excellent point, and one that I had overlooked in the
context of this discussion.

While were're on a psychological, social, and behavioral mood, let's
consider the effect of blood alcohol on driver connectivity. Alcohol is a
general nervous system depressant, and the ears are hooked to the brain via
the nervous system...

More powerful amplifiers also provide a psychoacoustic cause for speaker
damage. Undistorted music often sounds less loud than distorted music
with
equal power. Therefore, a listener is more likely to apply more power to
his
speakers with a more powerful amplifier. In the absence of clipping, the
music will not sound as loud as it will if it is clipped.

This is an excellent point, and one that I had overlooked in the context of
this discussion.

More powerful amplifiers also provide a psychoacoustic cause for speaker
damage. Undistorted music often sounds less loud than distorted music
with
equal power. Therefore, a listener is more likely to apply more power to
his
speakers with a more powerful amplifier. In the absence of clipping, the
music will not sound as loud as it will if it is clipped.

This is an excellent point, and one that I had overlooked in the context of
this discussion.

"MZ" wrote in message

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?

Unfortunately, it doesn't really clarify anything. In fact, it
muddies things up even more. First of all, there's not really such a
thing as "pulsating DC". That's an oxymoron. If it's "pulsating",
it's by definition an AC signal.

Your skepticism is IMO well-founded.

When you cleanly clip a music waveform, it doesn't just look like a square
wave, it is a variable-frequency square wave. However, there's no guarantee
that a true POS power amp will clip cleanly. What this comes down to is that
a POS is a POS, and using a POS power amp can be dangerous to your system,
no matter what its power rating is.

If we drop the POS power amps from the discussion, we're left with what
happens with a competent low power amp as opposed to what happens to a
competent high powered amp.

To understand this better, you have to consider how speakers fail. IME the
most common form of driver failure is caused by overheating of the voice
coil. Second is fracturing of the voice coil wiring due to excess flexing. A
third failure mode relates to over-travel of the cone. These three most
common loudspeaker driver failure modes have a common cause - too much
power.

Much has been written about spectral shifting due to clipping, and this can
clearly stimulate the first and second modes of failure by causing more
power to be routed to high frequency drivers.

However, there's a lot of music around whose high frequency spectral
content actually decreases when it is cleanly clipped, and even more where
there are no appreciable changes.

Classical music is one genre where upward spectral shifting can still be
dominant, but even there it's not a sure thing. During crescendos crashing
cymbals and blaring horns can build up a lot of power at high frequencies.

The bottom line is that most of the failure modes of drivers come from the
driver receiving too much power, too long. The easiest way to get more power
to a speaker is to have a more powerful amplifier. These days, 100 wpc power
amps are unbelievably inexpensive. 100 wpc is a lot of power for most
consumer speakers to handle, long term.

Intensely powerful *accidents* are more likely with more powerful
amplifiers.

More powerful amplifiers also provide a psychoacoustic cause for speaker
damage. Undistorted music often sounds less loud than distorted music with
equal power. Therefore, a listener is more likely to apply more power to his
speakers with a more powerful amplifier. In the absence of clipping, the
music will not sound as loud as it will if it is clipped.

That all said, I have just a few kilowatts of power amps around the house,
and most of them are hooked to speakers. The good news for my speakers is
that I have a lot of fairly robust speakers, and I try to be careful.

I don't think there is any doubt that over the past 30 years loudspeakers
have become as a rule, more robust.

"MZ" wrote in message

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?

Unfortunately, it doesn't really clarify anything. In fact, it
muddies things up even more. First of all, there's not really such a
thing as "pulsating DC". That's an oxymoron. If it's "pulsating",
it's by definition an AC signal.

Your skepticism is IMO well-founded.

When you cleanly clip a music waveform, it doesn't just look like a square
wave, it is a variable-frequency square wave. However, there's no guarantee
that a true POS power amp will clip cleanly. What this comes down to is that
a POS is a POS, and using a POS power amp can be dangerous to your system,
no matter what its power rating is.

If we drop the POS power amps from the discussion, we're left with what
happens with a competent low power amp as opposed to what happens to a
competent high powered amp.

To understand this better, you have to consider how speakers fail. IME the
most common form of driver failure is caused by overheating of the voice
coil. Second is fracturing of the voice coil wiring due to excess flexing. A
third failure mode relates to over-travel of the cone. These three most
common loudspeaker driver failure modes have a common cause - too much
power.

Much has been written about spectral shifting due to clipping, and this can
clearly stimulate the first and second modes of failure by causing more
power to be routed to high frequency drivers.

However, there's a lot of music around whose high frequency spectral
content actually decreases when it is cleanly clipped, and even more where
there are no appreciable changes.

Classical music is one genre where upward spectral shifting can still be
dominant, but even there it's not a sure thing. During crescendos crashing
cymbals and blaring horns can build up a lot of power at high frequencies.

The bottom line is that most of the failure modes of drivers come from the
driver receiving too much power, too long. The easiest way to get more power
to a speaker is to have a more powerful amplifier. These days, 100 wpc power
amps are unbelievably inexpensive. 100 wpc is a lot of power for most
consumer speakers to handle, long term.

Intensely powerful *accidents* are more likely with more powerful
amplifiers.

More powerful amplifiers also provide a psychoacoustic cause for speaker
damage. Undistorted music often sounds less loud than distorted music with
equal power. Therefore, a listener is more likely to apply more power to his
speakers with a more powerful amplifier. In the absence of clipping, the
music will not sound as loud as it will if it is clipped.

That all said, I have just a few kilowatts of power amps around the house,
and most of them are hooked to speakers. The good news for my speakers is
that I have a lot of fairly robust speakers, and I try to be careful.

I don't think there is any doubt that over the past 30 years loudspeakers
have become as a rule, more robust.

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?

Unfortunately, it doesn't really clarify anything. In fact, it muddies
things up even more. First of all, there's not really such a thing as
"pulsating DC". That's an oxymoron. If it's "pulsating", it's by
definition an AC signal.

The rest of what you say would be true only if the fundamental was on the
order of fractions of a Hz. It's a nice idea, but it's simply not the way
it works. The voice coil doesn't care a whole lot about the motion
waveform - it just cares that motion is occurring. Whether it's a square
wave or a sine wave, it makes no difference. Also, due to the inductance of
the voice coil and the limitations of the amplifier, most speakers will
generally not move in a square wave fashion anyway, even when the amplifier
is severely clipped.

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?

Unfortunately, it doesn't really clarify anything. In fact, it muddies
things up even more. First of all, there's not really such a thing as
"pulsating DC". That's an oxymoron. If it's "pulsating", it's by
definition an AC signal.

The rest of what you say would be true only if the fundamental was on the
order of fractions of a Hz. It's a nice idea, but it's simply not the way
it works. The voice coil doesn't care a whole lot about the motion
waveform - it just cares that motion is occurring. Whether it's a square
wave or a sine wave, it makes no difference. Also, due to the inductance of
the voice coil and the limitations of the amplifier, most speakers will
generally not move in a square wave fashion anyway, even when the amplifier
is severely clipped.

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/

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/

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.


An interesting response but perhaps a little anticdotal. The
shortest job that I ever had was once I was hired to be a
bricklayer's helper. I was healthy, but not a really strong guy.
I was strong enough to lift buckets of morter and concrete but
after a short while I would get a little shakey. I spilled some
concrete once or twice on a wall because of my lack of strength.
If they had hired a stronger guy, it wouldn't have happened. If
they had hired a 3 year old kid, it ALSO wouldn't have happened
since the kid wouldn't have had the strength to even lift the
bucket in the first place. To say that the damage I caused was
not due to my lack of strength/control and say the proof is that
someone with even less strengh wouldn't cause any damage seems to
ignores some key elements of logic somewhere :-)

The problem is where there is enough power to get things going
but not enough to control things well. If my boss missed the
issue and somehow thought I could do twice as much work, he might
of made me carry two buckets at a time (like the other "Charles
Atlas" helper he had). Since I COULD lift two buckets, you might
say I could do it, but I suspect that there would have been twice
as much damage.

The issue with the speaker ratings is that they never tell you
how the rated power can be safely distributed across the spectrum
of the speaker or how they even arrived at the rating in the
first place. A "50 watt" speaker may only be rated for 1/4 watt
across the 5KHz to 20KHz band. As has been pointed out before, a
speaker rating is not linear across its entire bandwidth.

There may be some standards for speaker power rating but I don't
think that I've ever come across one.

- Jeff

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.


An interesting response but perhaps a little anticdotal. The
shortest job that I ever had was once I was hired to be a
bricklayer's helper. I was healthy, but not a really strong guy.
I was strong enough to lift buckets of morter and concrete but
after a short while I would get a little shakey. I spilled some
concrete once or twice on a wall because of my lack of strength.
If they had hired a stronger guy, it wouldn't have happened. If
they had hired a 3 year old kid, it ALSO wouldn't have happened
since the kid wouldn't have had the strength to even lift the
bucket in the first place. To say that the damage I caused was
not due to my lack of strength/control and say the proof is that
someone with even less strengh wouldn't cause any damage seems to
ignores some key elements of logic somewhere :-)

The problem is where there is enough power to get things going
but not enough to control things well. If my boss missed the
issue and somehow thought I could do twice as much work, he might
of made me carry two buckets at a time (like the other "Charles
Atlas" helper he had). Since I COULD lift two buckets, you might
say I could do it, but I suspect that there would have been twice
as much damage.

The issue with the speaker ratings is that they never tell you
how the rated power can be safely distributed across the spectrum
of the speaker or how they even arrived at the rating in the
first place. A "50 watt" speaker may only be rated for 1/4 watt
across the 5KHz to 20KHz band. As has been pointed out before, a
speaker rating is not linear across its entire bandwidth.

There may be some standards for speaker power rating but I don't
think that I've ever come across one.

- Jeff