"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.

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.

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...

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...

I don't know of any evidence that suggests that alcohol would have an
influence on loudness perception, though it almost certainly would
contribute to the stupidity factor - that is, turning it up beyond reason.

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...

I don't know of any evidence that suggests that alcohol would have an
influence on loudness perception, though it almost certainly would
contribute to the stupidity factor - that is, turning it up beyond reason.

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...

I don't know of any evidence that suggests that alcohol would have an
influence on loudness perception, though it almost certainly would
contribute to the stupidity factor - that is, turning it up beyond reason.

"MZ" wrote in message

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...

I don't know of any evidence that suggests that alcohol would have an
influence on loudness perception, though it almost certainly would
contribute to the stupidity factor - that is, turning it up beyond
reason.


http://alcoholism.about.com/cs/brain/a/blacer040314.htm

http://hearingloss.upmc.com/Treatment.htm

"MZ" wrote in message

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...

I don't know of any evidence that suggests that alcohol would have an
influence on loudness perception, though it almost certainly would
contribute to the stupidity factor - that is, turning it up beyond
reason.


http://alcoholism.about.com/cs/brain/a/blacer040314.htm

http://hearingloss.upmc.com/Treatment.htm

"MZ" wrote in message

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...

I don't know of any evidence that suggests that alcohol would have an
influence on loudness perception, though it almost certainly would
contribute to the stupidity factor - that is, turning it up beyond
reason.


http://alcoholism.about.com/cs/brain/a/blacer040314.htm

http://hearingloss.upmc.com/Treatment.htm

Jeff Wiseman wrote in message ...
Jean wrote:

"Billw" wrote in message ...
"Jean" wrote in message
om...
Hello,
I have an audio amp, 40 watts RMS per channel (8 ohm) and I would like
to plug to one channel a small speaker 19 watts (8 ohm).

4 questions:
1- What circuit should I build to adapt?

none. just connect it. The power in your program signal is NOT the full
power of the amplifier.

And after that, if it sounds bad, turn it down.

Unless you plan to pound the amp at clipping levels constantly (i.e., use it
as a guitar amp), there is very little danger of hurting the speaker with
too much power (you're probably more likely to hurt it with too LITTLE
power). If you plan to abuse the volume control (play loud without regard
to how much it is disorting), though, then you may need to watch out.


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).


Then, what is the purpose to have a loudspeaker (on a HI-FI audio amp)
with enough power to be driven by the amp? ( I use my amp only for
music)


That really is kinda reversed. You want an amp that can produce
clean undistorted power over the range that the speakers are
rated for.
...
The really important thing is, can you get the maximum volume
that you want to listen to out of the speakers with it sounding
clean and without distortion?
- Jeff

My situation: I already have a Hi-Fi amp 40 watts. I have extra
loudspeakers 19 watts. I do not want to damage my 19 watts. I am not
concerned about distortion because my guess ( before plugging my 19
watts) is if I put the volume 40 watts at 10/10, I will damage my 19
watts, tweeters probably first than woofers as I understand from the
postings...
The really important thing is getting max volume 10/10 from a kid not
without distortion, but without damaging my 19 watts loudspeakers.
I could try this: plug the 19 watts, take up the volume to 5/10
(20watts?), 6/10 (24 watts?)... 10/10 (40 watts) and see at what level
I blow up the 19 watts speakers?
I wanted to adapt the power so that if a kid turn the volume 10/10,
yes, the 19 watts speakers are still reproducing the sound.
Then I will think about distortion: If I hear distortion, it is
because the loudspeaker is not able to reproduce the music, then
because there is too much power sent to the speaker: therefore, turn
dowm the volume!
A 1 watt speaker is able to reproduce a 1000 watt amp if you do not
turn the volume at 10/10! You have to adapt in some ways ( which is
the first question ) to keep alive the 1 watt speaker. Then I will
think about a clean reproduction of the music...

Jeff Wiseman wrote in message ...
Jean wrote:

"Billw" wrote in message ...
"Jean" wrote in message
om...
Hello,
I have an audio amp, 40 watts RMS per channel (8 ohm) and I would like
to plug to one channel a small speaker 19 watts (8 ohm).

4 questions:
1- What circuit should I build to adapt?

none. just connect it. The power in your program signal is NOT the full
power of the amplifier.

And after that, if it sounds bad, turn it down.

Unless you plan to pound the amp at clipping levels constantly (i.e., use it
as a guitar amp), there is very little danger of hurting the speaker with
too much power (you're probably more likely to hurt it with too LITTLE
power). If you plan to abuse the volume control (play loud without regard
to how much it is disorting), though, then you may need to watch out.


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).


Then, what is the purpose to have a loudspeaker (on a HI-FI audio amp)
with enough power to be driven by the amp? ( I use my amp only for
music)


That really is kinda reversed. You want an amp that can produce
clean undistorted power over the range that the speakers are
rated for.
...
The really important thing is, can you get the maximum volume
that you want to listen to out of the speakers with it sounding
clean and without distortion?
- Jeff

My situation: I already have a Hi-Fi amp 40 watts. I have extra
loudspeakers 19 watts. I do not want to damage my 19 watts. I am not
concerned about distortion because my guess ( before plugging my 19
watts) is if I put the volume 40 watts at 10/10, I will damage my 19
watts, tweeters probably first than woofers as I understand from the
postings...
The really important thing is getting max volume 10/10 from a kid not
without distortion, but without damaging my 19 watts loudspeakers.
I could try this: plug the 19 watts, take up the volume to 5/10
(20watts?), 6/10 (24 watts?)... 10/10 (40 watts) and see at what level
I blow up the 19 watts speakers?
I wanted to adapt the power so that if a kid turn the volume 10/10,
yes, the 19 watts speakers are still reproducing the sound.
Then I will think about distortion: If I hear distortion, it is
because the loudspeaker is not able to reproduce the music, then
because there is too much power sent to the speaker: therefore, turn
dowm the volume!
A 1 watt speaker is able to reproduce a 1000 watt amp if you do not
turn the volume at 10/10! You have to adapt in some ways ( which is
the first question ) to keep alive the 1 watt speaker. Then I will
think about a clean reproduction of the music...

Jeff Wiseman wrote in message ...
Jean wrote:

"Billw" wrote in message ...
"Jean" wrote in message
om...
Hello,
I have an audio amp, 40 watts RMS per channel (8 ohm) and I would like
to plug to one channel a small speaker 19 watts (8 ohm).

4 questions:
1- What circuit should I build to adapt?

none. just connect it. The power in your program signal is NOT the full
power of the amplifier.

And after that, if it sounds bad, turn it down.

Unless you plan to pound the amp at clipping levels constantly (i.e., use it
as a guitar amp), there is very little danger of hurting the speaker with
too much power (you're probably more likely to hurt it with too LITTLE
power). If you plan to abuse the volume control (play loud without regard
to how much it is disorting), though, then you may need to watch out.


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).


Then, what is the purpose to have a loudspeaker (on a HI-FI audio amp)
with enough power to be driven by the amp? ( I use my amp only for
music)


That really is kinda reversed. You want an amp that can produce
clean undistorted power over the range that the speakers are
rated for.
...
The really important thing is, can you get the maximum volume
that you want to listen to out of the speakers with it sounding
clean and without distortion?
- Jeff

My situation: I already have a Hi-Fi amp 40 watts. I have extra
loudspeakers 19 watts. I do not want to damage my 19 watts. I am not
concerned about distortion because my guess ( before plugging my 19
watts) is if I put the volume 40 watts at 10/10, I will damage my 19
watts, tweeters probably first than woofers as I understand from the
postings...
The really important thing is getting max volume 10/10 from a kid not
without distortion, but without damaging my 19 watts loudspeakers.
I could try this: plug the 19 watts, take up the volume to 5/10
(20watts?), 6/10 (24 watts?)... 10/10 (40 watts) and see at what level
I blow up the 19 watts speakers?
I wanted to adapt the power so that if a kid turn the volume 10/10,
yes, the 19 watts speakers are still reproducing the sound.
Then I will think about distortion: If I hear distortion, it is
because the loudspeaker is not able to reproduce the music, then
because there is too much power sent to the speaker: therefore, turn
dowm the volume!
A 1 watt speaker is able to reproduce a 1000 watt amp if you do not
turn the volume at 10/10! You have to adapt in some ways ( which is
the first question ) to keep alive the 1 watt speaker. Then I will
think about a clean reproduction of the music...

http://alcoholism.about.com/cs/brain/a/blacer040314.htm

http://hearingloss.upmc.com/Treatment.htm

This is something entirely different. These links refer to central loss of
function as a result of chronic alcoholism, rather than event-related
conditions.

http://alcoholism.about.com/cs/brain/a/blacer040314.htm

http://hearingloss.upmc.com/Treatment.htm

This is something entirely different. These links refer to central loss of
function as a result of chronic alcoholism, rather than event-related
conditions.

http://alcoholism.about.com/cs/brain/a/blacer040314.htm

http://hearingloss.upmc.com/Treatment.htm

This is something entirely different. These links refer to central loss of
function as a result of chronic alcoholism, rather than event-related
conditions.

Jean wrote:
My situation: I already have a Hi-Fi amp 40 watts. I have extra
loudspeakers 19 watts. I do not want to damage my 19 watts. I am not
concerned about distortion because my guess ( before plugging my 19
watts) is if I put the volume 40 watts at 10/10, I will damage my 19
watts, tweeters probably first than woofers as I understand from the
postings...

In general, putting the setting at 10/10 will cause damage on
most systems anyway if left running long enough.


The really important thing is getting max volume 10/10 from a kid not
without distortion, but without damaging my 19 watts loudspeakers.
I could try this: plug the 19 watts, take up the volume to 5/10
(20watts?), 6/10 (24 watts?)... 10/10 (40 watts) and see at what level
I blow up the 19 watts speakers?
I wanted to adapt the power so that if a kid turn the volume 10/10,
yes, the 19 watts speakers are still reproducing the sound.


Ahh! NOW we're getting to the crux of the matter :-) Cranking the
volume up to 100% on most systems will usually result in a
failure given long enough to heat things up. That's why most
people don't do it :-) I once had a 125watt receiver that my 2
year old daughter cranked up all the way when it was off. She
then made the mistake of pushing the power button! I was in the
house as was able to turn it off before any real damage occurred
but I suspect it was close :-) Suggestions for this at the end of
this note:


Then I will think about distortion: If I hear distortion, it is
because the loudspeaker is not able to reproduce the music, then
because there is too much power sent to the speaker: therefore, turn
dowm the volume!


Exactly. If your amp is rated higher than the speakers, in
general when you start to hear distortion, is because the
speakers are being pushed to hard.


A 1 watt speaker is able to reproduce a 1000 watt amp if you do not
turn the volume at 10/10! You have to adapt in some ways ( which is
the first question ) to keep alive the 1 watt speaker. Then I will
think about a clean reproduction of the music...


OK, here's a way to deal with it but it assumes that you can get
to the signal between your preamp and your main amp. The issue is
that you don't want the signal entering the amp to be high enough
to create a damaging level of signal to the speakers. I solved my
problem as followes:

Although I had a receiver at the time, the preamp and power amp
sections were separated by a pair of jumpers on the back. I
removed the jumpers and put a "T-pad" resistor in using a value
so that when my volume level was up all the way, the total volume
in the room was only slightly louder than I normally listened to.
By putting the resistance between the preamp and the main amp, it
prevented the amp itself from being overdriven into distortion
even when the preamp's volume was up all the way. In other words,
even though the main amp was rated for 125 watts, I was
preventing it from getting enough signal to ever reach that level.

I used a pair of T-pads but I also could have just used a stereo
potentiometer (about a 50Kohm unit wired across the output of the
preamp with the common and tap going to the main amp) adjusted to
limit the maximum volume in the room when the preamp's volume was
set to 100%. I had to make them myself as I couldn't find
something off the self. I'm not sure where you might find
something like this pre-built but anyone handly with a soldering
iron could put something like that together real cheap.

- Jeff

Jean wrote:
My situation: I already have a Hi-Fi amp 40 watts. I have extra
loudspeakers 19 watts. I do not want to damage my 19 watts. I am not
concerned about distortion because my guess ( before plugging my 19
watts) is if I put the volume 40 watts at 10/10, I will damage my 19
watts, tweeters probably first than woofers as I understand from the
postings...

In general, putting the setting at 10/10 will cause damage on
most systems anyway if left running long enough.


The really important thing is getting max volume 10/10 from a kid not
without distortion, but without damaging my 19 watts loudspeakers.
I could try this: plug the 19 watts, take up the volume to 5/10
(20watts?), 6/10 (24 watts?)... 10/10 (40 watts) and see at what level
I blow up the 19 watts speakers?
I wanted to adapt the power so that if a kid turn the volume 10/10,
yes, the 19 watts speakers are still reproducing the sound.


Ahh! NOW we're getting to the crux of the matter :-) Cranking the
volume up to 100% on most systems will usually result in a
failure given long enough to heat things up. That's why most
people don't do it :-) I once had a 125watt receiver that my 2
year old daughter cranked up all the way when it was off. She
then made the mistake of pushing the power button! I was in the
house as was able to turn it off before any real damage occurred
but I suspect it was close :-) Suggestions for this at the end of
this note:


Then I will think about distortion: If I hear distortion, it is
because the loudspeaker is not able to reproduce the music, then
because there is too much power sent to the speaker: therefore, turn
dowm the volume!


Exactly. If your amp is rated higher than the speakers, in
general when you start to hear distortion, is because the
speakers are being pushed to hard.


A 1 watt speaker is able to reproduce a 1000 watt amp if you do not
turn the volume at 10/10! You have to adapt in some ways ( which is
the first question ) to keep alive the 1 watt speaker. Then I will
think about a clean reproduction of the music...


OK, here's a way to deal with it but it assumes that you can get
to the signal between your preamp and your main amp. The issue is
that you don't want the signal entering the amp to be high enough
to create a damaging level of signal to the speakers. I solved my
problem as followes:

Although I had a receiver at the time, the preamp and power amp
sections were separated by a pair of jumpers on the back. I
removed the jumpers and put a "T-pad" resistor in using a value
so that when my volume level was up all the way, the total volume
in the room was only slightly louder than I normally listened to.
By putting the resistance between the preamp and the main amp, it
prevented the amp itself from being overdriven into distortion
even when the preamp's volume was up all the way. In other words,
even though the main amp was rated for 125 watts, I was
preventing it from getting enough signal to ever reach that level.

I used a pair of T-pads but I also could have just used a stereo
potentiometer (about a 50Kohm unit wired across the output of the
preamp with the common and tap going to the main amp) adjusted to
limit the maximum volume in the room when the preamp's volume was
set to 100%. I had to make them myself as I couldn't find
something off the self. I'm not sure where you might find
something like this pre-built but anyone handly with a soldering
iron could put something like that together real cheap.

- Jeff

Jean wrote:
My situation: I already have a Hi-Fi amp 40 watts. I have extra
loudspeakers 19 watts. I do not want to damage my 19 watts. I am not
concerned about distortion because my guess ( before plugging my 19
watts) is if I put the volume 40 watts at 10/10, I will damage my 19
watts, tweeters probably first than woofers as I understand from the
postings...

In general, putting the setting at 10/10 will cause damage on
most systems anyway if left running long enough.


The really important thing is getting max volume 10/10 from a kid not
without distortion, but without damaging my 19 watts loudspeakers.
I could try this: plug the 19 watts, take up the volume to 5/10
(20watts?), 6/10 (24 watts?)... 10/10 (40 watts) and see at what level
I blow up the 19 watts speakers?
I wanted to adapt the power so that if a kid turn the volume 10/10,
yes, the 19 watts speakers are still reproducing the sound.


Ahh! NOW we're getting to the crux of the matter :-) Cranking the
volume up to 100% on most systems will usually result in a
failure given long enough to heat things up. That's why most
people don't do it :-) I once had a 125watt receiver that my 2
year old daughter cranked up all the way when it was off. She
then made the mistake of pushing the power button! I was in the
house as was able to turn it off before any real damage occurred
but I suspect it was close :-) Suggestions for this at the end of
this note:


Then I will think about distortion: If I hear distortion, it is
because the loudspeaker is not able to reproduce the music, then
because there is too much power sent to the speaker: therefore, turn
dowm the volume!


Exactly. If your amp is rated higher than the speakers, in
general when you start to hear distortion, is because the
speakers are being pushed to hard.


A 1 watt speaker is able to reproduce a 1000 watt amp if you do not
turn the volume at 10/10! You have to adapt in some ways ( which is
the first question ) to keep alive the 1 watt speaker. Then I will
think about a clean reproduction of the music...


OK, here's a way to deal with it but it assumes that you can get
to the signal between your preamp and your main amp. The issue is
that you don't want the signal entering the amp to be high enough
to create a damaging level of signal to the speakers. I solved my
problem as followes:

Although I had a receiver at the time, the preamp and power amp
sections were separated by a pair of jumpers on the back. I
removed the jumpers and put a "T-pad" resistor in using a value
so that when my volume level was up all the way, the total volume
in the room was only slightly louder than I normally listened to.
By putting the resistance between the preamp and the main amp, it
prevented the amp itself from being overdriven into distortion
even when the preamp's volume was up all the way. In other words,
even though the main amp was rated for 125 watts, I was
preventing it from getting enough signal to ever reach that level.

I used a pair of T-pads but I also could have just used a stereo
potentiometer (about a 50Kohm unit wired across the output of the
preamp with the common and tap going to the main amp) adjusted to
limit the maximum volume in the room when the preamp's volume was
set to 100%. I had to make them myself as I couldn't find
something off the self. I'm not sure where you might find
something like this pre-built but anyone handly with a soldering
iron could put something like that together real cheap.

- Jeff

just put a 1 or 2 ampere fuse in the speaker line and forget about it.

On 22 Jun 2004 13:54:11 -0700, (Jean) wrote:

Hello,
I have an audio amp, 40 watts RMS per channel (8 ohm) and I would like
to plug to one channel a small speaker 19 watts (8 ohm).

4 questions:
1- What circuit should I build to adapt?

2- How can I know how much ampere the amp is using to drive one
loudspeaker?

3- A better suitable newsgroup to post this question?

Search on the internet:
4- What words should I use to find some appropriate technical texts?

Thank you.

just put a 1 or 2 ampere fuse in the speaker line and forget about it.

On 22 Jun 2004 13:54:11 -0700, (Jean) wrote:

Hello,
I have an audio amp, 40 watts RMS per channel (8 ohm) and I would like
to plug to one channel a small speaker 19 watts (8 ohm).

4 questions:
1- What circuit should I build to adapt?

2- How can I know how much ampere the amp is using to drive one
loudspeaker?

3- A better suitable newsgroup to post this question?

Search on the internet:
4- What words should I use to find some appropriate technical texts?

Thank you.

just put a 1 or 2 ampere fuse in the speaker line and forget about it.

On 22 Jun 2004 13:54:11 -0700, (Jean) wrote:

Hello,
I have an audio amp, 40 watts RMS per channel (8 ohm) and I would like
to plug to one channel a small speaker 19 watts (8 ohm).

4 questions:
1- What circuit should I build to adapt?

2- How can I know how much ampere the amp is using to drive one
loudspeaker?

3- A better suitable newsgroup to post this question?

Search on the internet:
4- What words should I use to find some appropriate technical texts?

Thank you.

"Stu-R" wrote in message
...
just put a 1 or 2 ampere fuse in the speaker line and forget about it.

On 22 Jun 2004 13:54:11 -0700, (Jean) wrote:

Hello,
I have an audio amp, 40 watts RMS per channel (8 ohm) and I would like
to plug to one channel a small speaker 19 watts (8 ohm).

4 questions:
1- What circuit should I build to adapt?

2- How can I know how much ampere the amp is using to drive one
loudspeaker?

3- A better suitable newsgroup to post this question?

Search on the internet:
4- What words should I use to find some appropriate technical texts?

Thank you.


I agree. Fuse the speaker and forget it. P = (I^2) * R. Solving for I, the
maximum current at 19 watts would be 1.5 amps. I'd use a 1.0 amp fast-blow
fuse to be safe.

To put things in perspective, the difference between 40 watts and 19 watts
just a little over 3 dB. In other words, you could make the 40 watt
amplifier "safe" for the 19 watt speaker by turning down the volume by 3dB,
a barely audible difference.

"Stu-R" wrote in message
...
just put a 1 or 2 ampere fuse in the speaker line and forget about it.

On 22 Jun 2004 13:54:11 -0700, (Jean) wrote:

Hello,
I have an audio amp, 40 watts RMS per channel (8 ohm) and I would like
to plug to one channel a small speaker 19 watts (8 ohm).

4 questions:
1- What circuit should I build to adapt?

2- How can I know how much ampere the amp is using to drive one
loudspeaker?

3- A better suitable newsgroup to post this question?

Search on the internet:
4- What words should I use to find some appropriate technical texts?

Thank you.


I agree. Fuse the speaker and forget it. P = (I^2) * R. Solving for I, the
maximum current at 19 watts would be 1.5 amps. I'd use a 1.0 amp fast-blow
fuse to be safe.

To put things in perspective, the difference between 40 watts and 19 watts
just a little over 3 dB. In other words, you could make the 40 watt
amplifier "safe" for the 19 watt speaker by turning down the volume by 3dB,
a barely audible difference.

"Stu-R" wrote in message
...
just put a 1 or 2 ampere fuse in the speaker line and forget about it.

On 22 Jun 2004 13:54:11 -0700, (Jean) wrote:

Hello,
I have an audio amp, 40 watts RMS per channel (8 ohm) and I would like
to plug to one channel a small speaker 19 watts (8 ohm).

4 questions:
1- What circuit should I build to adapt?

2- How can I know how much ampere the amp is using to drive one
loudspeaker?

3- A better suitable newsgroup to post this question?

Search on the internet:
4- What words should I use to find some appropriate technical texts?

Thank you.


I agree. Fuse the speaker and forget it. P = (I^2) * R. Solving for I, the
maximum current at 19 watts would be 1.5 amps. I'd use a 1.0 amp fast-blow
fuse to be safe.

To put things in perspective, the difference between 40 watts and 19 watts
just a little over 3 dB. In other words, you could make the 40 watt
amplifier "safe" for the 19 watt speaker by turning down the volume by 3dB,
a barely audible difference.

I agree. Fuse the speaker and forget it. P = (I^2) * R. Solving for I,
the
maximum current at 19 watts would be 1.5 amps. I'd use a 1.0 amp fast-blow
fuse to be safe.

To put things in perspective, the difference between 40 watts and 19 watts
just a little over 3 dB. In other words, you could make the 40 watt
amplifier "safe" for the 19 watt speaker by turning down the volume by
3dB,
a barely audible difference.

3dB is most certainly audible. Especially across the entire spectrum.

I agree. Fuse the speaker and forget it. P = (I^2) * R. Solving for I,
the
maximum current at 19 watts would be 1.5 amps. I'd use a 1.0 amp fast-blow
fuse to be safe.

To put things in perspective, the difference between 40 watts and 19 watts
just a little over 3 dB. In other words, you could make the 40 watt
amplifier "safe" for the 19 watt speaker by turning down the volume by
3dB,
a barely audible difference.

3dB is most certainly audible. Especially across the entire spectrum.

I agree. Fuse the speaker and forget it. P = (I^2) * R. Solving for I,
the
maximum current at 19 watts would be 1.5 amps. I'd use a 1.0 amp fast-blow
fuse to be safe.

To put things in perspective, the difference between 40 watts and 19 watts
just a little over 3 dB. In other words, you could make the 40 watt
amplifier "safe" for the 19 watt speaker by turning down the volume by
3dB,
a barely audible difference.

3dB is most certainly audible. Especially across the entire spectrum.

On Sat, 26 Jun 2004 02:10:33 -0400, "MZ"
wrote:

I agree. Fuse the speaker and forget it. P = (I^2) * R. Solving for I,
the
maximum current at 19 watts would be 1.5 amps. I'd use a 1.0 amp fast-blow
fuse to be safe.

To put things in perspective, the difference between 40 watts and 19 watts
just a little over 3 dB. In other words, you could make the 40 watt
amplifier "safe" for the 19 watt speaker by turning down the volume by
3dB,
a barely audible difference.

3dB is most certainly audible. Especially across the entire spectrum.


A 3dB change in sound level is, as you say, very audible. But to
substitute an amplifier, a job which would take several minutes, with
another of 3dB lower power - and then tell which was which - would not
be easy. Judging the difference in loudness at which clipping starts
isn't easy at all.

d
Pearce Consulting
http://www.pearce.uk.com

On Sat, 26 Jun 2004 02:10:33 -0400, "MZ"
wrote:

I agree. Fuse the speaker and forget it. P = (I^2) * R. Solving for I,
the
maximum current at 19 watts would be 1.5 amps. I'd use a 1.0 amp fast-blow
fuse to be safe.

To put things in perspective, the difference between 40 watts and 19 watts
just a little over 3 dB. In other words, you could make the 40 watt
amplifier "safe" for the 19 watt speaker by turning down the volume by
3dB,
a barely audible difference.

3dB is most certainly audible. Especially across the entire spectrum.


A 3dB change in sound level is, as you say, very audible. But to
substitute an amplifier, a job which would take several minutes, with
another of 3dB lower power - and then tell which was which - would not
be easy. Judging the difference in loudness at which clipping starts
isn't easy at all.

d
Pearce Consulting
http://www.pearce.uk.com

On Sat, 26 Jun 2004 02:10:33 -0400, "MZ"
wrote:

I agree. Fuse the speaker and forget it. P = (I^2) * R. Solving for I,
the
maximum current at 19 watts would be 1.5 amps. I'd use a 1.0 amp fast-blow
fuse to be safe.

To put things in perspective, the difference between 40 watts and 19 watts
just a little over 3 dB. In other words, you could make the 40 watt
amplifier "safe" for the 19 watt speaker by turning down the volume by
3dB,
a barely audible difference.

3dB is most certainly audible. Especially across the entire spectrum.


A 3dB change in sound level is, as you say, very audible. But to
substitute an amplifier, a job which would take several minutes, with
another of 3dB lower power - and then tell which was which - would not
be easy. Judging the difference in loudness at which clipping starts
isn't easy at all.

d
Pearce Consulting
http://www.pearce.uk.com

"MZ" wrote in message
...
I've done in many many times. What are you getting at? Yes, the high
frequency content increases! That's my entire point. And what Rane is
saying is the same thing.

No they are not. The whole article is to contradict your notions, but it
seems you still don't get it.

It's simply too much power and (thermal) compression that
kills speakers, with or without signal distortion.

Exactly.

Yes, too much power will blow speakers. Who argued otherwise? Certainly
not me.

Why all the nonsense about "clipping increasing HF components" being the
problem then? And the assertion that bigger amps are safer.

I don't know what "thermal compression" is. Power compression
perhaps? That won't blow speakers. In fact, it acts in the opposite
manner.

Not at all, since the average power increases and it is the average power
that will kill tweeters, regardless of spectral content (assuming a proper
Xover)

TonyP.

"MZ" wrote in message
...
I've done in many many times. What are you getting at? Yes, the high
frequency content increases! That's my entire point. And what Rane is
saying is the same thing.

No they are not. The whole article is to contradict your notions, but it
seems you still don't get it.

It's simply too much power and (thermal) compression that
kills speakers, with or without signal distortion.

Exactly.

Yes, too much power will blow speakers. Who argued otherwise? Certainly
not me.

Why all the nonsense about "clipping increasing HF components" being the
problem then? And the assertion that bigger amps are safer.

I don't know what "thermal compression" is. Power compression
perhaps? That won't blow speakers. In fact, it acts in the opposite
manner.

Not at all, since the average power increases and it is the average power
that will kill tweeters, regardless of spectral content (assuming a proper
Xover)

TonyP.

"MZ" wrote in message
...
I've done in many many times. What are you getting at? Yes, the high
frequency content increases! That's my entire point. And what Rane is
saying is the same thing.

No they are not. The whole article is to contradict your notions, but it
seems you still don't get it.

It's simply too much power and (thermal) compression that
kills speakers, with or without signal distortion.

Exactly.

Yes, too much power will blow speakers. Who argued otherwise? Certainly
not me.

Why all the nonsense about "clipping increasing HF components" being the
problem then? And the assertion that bigger amps are safer.

I don't know what "thermal compression" is. Power compression
perhaps? That won't blow speakers. In fact, it acts in the opposite
manner.

Not at all, since the average power increases and it is the average power
that will kill tweeters, regardless of spectral content (assuming a proper
Xover)

TonyP.

"MZ" wrote in message
...
I agree. Fuse the speaker and forget it. P = (I^2) * R. Solving for I,
the
maximum current at 19 watts would be 1.5 amps. I'd use a 1.0 amp
fast-blow
fuse to be safe.

To put things in perspective, the difference between 40 watts and 19
watts
just a little over 3 dB. In other words, you could make the 40 watt
amplifier "safe" for the 19 watt speaker by turning down the volume by
3dB,
a barely audible difference.

3dB is most certainly audible. Especially across the entire spectrum.


I didn't say it wasn't audible. I just said it was barely audible. If I
thought I was going to have to footnote my post, I would have said it
wouldn't be noticed by the average person, listening casually to normal
programming (not tones or other highly correlated or highly uniform
signals). Sheesh.

"MZ" wrote in message
...
I agree. Fuse the speaker and forget it. P = (I^2) * R. Solving for I,
the
maximum current at 19 watts would be 1.5 amps. I'd use a 1.0 amp
fast-blow
fuse to be safe.

To put things in perspective, the difference between 40 watts and 19
watts
just a little over 3 dB. In other words, you could make the 40 watt
amplifier "safe" for the 19 watt speaker by turning down the volume by
3dB,
a barely audible difference.

3dB is most certainly audible. Especially across the entire spectrum.


I didn't say it wasn't audible. I just said it was barely audible. If I
thought I was going to have to footnote my post, I would have said it
wouldn't be noticed by the average person, listening casually to normal
programming (not tones or other highly correlated or highly uniform
signals). Sheesh.