I am hoping that someone would be able to offer some insight into a
speaker configuration problem I'm having. I have built an mp3 jukebox
and have installed 3 full range speakers into the cabinet (full range
so I didn't have to bother with cross over networks).

My amp delivers 70watts into 4Ohms, my speaker configuration consists
of 2 x 50watt 8 Ohms speakers in one parallel leg(giving me 4 Ohms)
and 1 80watt 4Ohms speaker in series with the parallel leg. So 2 x
4Ohms in series gives me 8Ohms. This ofcourse should mean my amp will
deliver only half its stated output (therefore, should be delivering
35watts). My problem is the lager 4Ohms 80watt speaker that is in
series with the parallel leg has burn't out. I have no idea why.

----8Ohms---- (50watts)
| |
| |
----8Ohms---- (50watts)
| |
| -------4Ohms------- (80watts)
| |

I read a similar reply recently that stated maybe its because the
wattage is unbalanced or the number of speakers were unbalanced,
resulting in the 4Ohms 80watt speaker doing double the work.

Please help if you can, any insight into this problem would be greatly
appreciated, its driving me nuts..

Thanks in advance Steve

1. YOu cannot be certain that the speaker ratings are accurate.
2. You cannot state that the 8ohm load will result in your amp
supplying only half power. It depends on the current capability of
the amp.
3. The so-called 80watt speaker is in series with the now 100watt
pair and any power disipated goes through both.

Kal


On 28 Oct 2003 08:24:46 -0800, (steven robinson)
wrote:

I am hoping that someone would be able to offer some insight into a
speaker configuration problem I'm having. I have built an mp3 jukebox
and have installed 3 full range speakers into the cabinet (full range
so I didn't have to bother with cross over networks).

My amp delivers 70watts into 4Ohms, my speaker configuration consists
of 2 x 50watt 8 Ohms speakers in one parallel leg(giving me 4 Ohms)
and 1 80watt 4Ohms speaker in series with the parallel leg. So 2 x
4Ohms in series gives me 8Ohms. This ofcourse should mean my amp will
deliver only half its stated output (therefore, should be delivering
35watts). My problem is the lager 4Ohms 80watt speaker that is in
series with the parallel leg has burn't out. I have no idea why.

----8Ohms---- (50watts)
| |
| |
----8Ohms---- (50watts)
| |
| -------4Ohms------- (80watts)
| |

I read a similar reply recently that stated maybe its because the
wattage is unbalanced or the number of speakers were unbalanced,
resulting in the 4Ohms 80watt speaker doing double the work.

Please help if you can, any insight into this problem would be greatly
appreciated, its driving me nuts..

Thanks in advance Steve

In article , Kalman Rubinson
wrote:
3. The so-called 80watt speaker is in series with the now 100watt pair
and any power disipated goes through both.

Not sure what you mean by the above. Can you clarify?

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

On Tue, 28 Oct 2003 17:41:53 +0000 (GMT), Jim Lesurf
wrote:

In article , Kalman Rubinson
wrote:
3. The so-called 80watt speaker is in series with the now 100watt pair
and any power disipated goes through both.

Not sure what you mean by the above. Can you clarify?

Just from your wiring. All current must go through the 80watt speaker
which is in series with the paralleled others. Thus, it now becomes
the limiting power factor, further stressed by the non-linear drive
imposed on it by the others.

I wish I could suggest a solution but I do not know your goals.

Kal

In article , Kalman Rubinson
wrote:
On Tue, 28 Oct 2003 17:41:53 +0000 (GMT), Jim Lesurf
wrote:

In article , Kalman
Rubinson wrote:
3. The so-called 80watt speaker is in series with the now 100watt
pair and any power disipated goes through both.

Not sure what you mean by the above. Can you clarify?

Just from your wiring.

The wiring was, I think, Steven's, not mine.

All current must go through the 80watt speaker which is in series with
the paralleled others.

Erm... Current is not power. They are quite distinct physical quantities,
albeit ones which have a specific relationship for a specific component.

The current will pass through the '80 watt' speaker, but this does not
necessarily mean that the 'power' passes though the speaker on its way to
the others. This is because the actual power is conveyed by the EM fields,
and the 80 Watt speaker has no way to know what electric potential
('voltage') is across any *other* loads in series with it. Hence it does
not actually experience the power being dissipated by the other units.

Thus, it now becomes the limiting power factor,

Afraid that, again, I'm not quite sure why you are saying this. Each
individual speaker unit has no awareness as such of what voltages or
currents or powers any *other* units experience. It only knows about the
potential between its own terminals, and the current that it then passes.

further stressed by the non-linear drive imposed on it by the others.

Are you talking about non-linear impedance here? if so, I'm unsure why. My
own comments on what Steven said were based upon things like frequency
dependence, and linear acoustic effects, not signal-level dependence.

I wish I could suggest a solution but I do not know your goals.

I assume that you mean Steven's goals. :-) My own recommendation to him
would be to avoid using dissimilar speakers in series.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

On Wed, 29 Oct 2003 16:59:50 +0000 (GMT), Jim Lesurf
wrote:


The current will pass through the '80 watt' speaker, but this does not
necessarily mean that the 'power' passes though the speaker on its way to
the others. This is because the actual power is conveyed by the EM fields,
and the 80 Watt speaker has no way to know what electric potential
('voltage') is across any *other* loads in series with it. Hence it does
not actually experience the power being dissipated by the other units.

Thus, it now becomes the limiting power factor,

Afraid that, again, I'm not quite sure why you are saying this. Each
individual speaker unit has no awareness as such of what voltages or
currents or powers any *other* units experience. It only knows about the
potential between its own terminals, and the current that it then passes.


Current is measured in amps. If two units are connected in series,
the same amperage will flow through both. If not, where would it go?
The resistance of each unit will determine how much power is drawn by
it.

"Power is conveyed by the EM fields" is meaningless gobbledygook.

On Wed, 29 Oct 2003 16:59:50 +0000 (GMT), Jim Lesurf
wrote:


The current will pass through the '80 watt' speaker, but this does not
necessarily mean that the 'power' passes though the speaker on its way to
the others. This is because the actual power is conveyed by the EM fields,
and the 80 Watt speaker has no way to know what electric potential
('voltage') is across any *other* loads in series with it. Hence it does
not actually experience the power being dissipated by the other units.

Thus, it now becomes the limiting power factor,

Afraid that, again, I'm not quite sure why you are saying this. Each
individual speaker unit has no awareness as such of what voltages or
currents or powers any *other* units experience. It only knows about the
potential between its own terminals, and the current that it then passes.


Current is measured in amps. If two units are connected in series,
the same amperage will flow through both. If not, where would it go?
The resistance of each unit will determine how much power is drawn by
it.

"Power is conveyed by the EM fields" is meaningless gobbledygook.

On Wed, 29 Oct 2003 16:59:50 +0000 (GMT), Jim Lesurf
wrote:

All current must go through the 80watt speaker which is in series with
the paralleled others.

Erm... Current is not power. They are quite distinct physical quantities,
albeit ones which have a specific relationship for a specific component.

If the 80watter is in series with the others (my interpretation of the
wiring) then all the current passes through it. What power it
dissipates, of course, depends on its own construction.

Thus, it now becomes the limiting power factor,

Afraid that, again, I'm not quite sure why you are saying this. Each
individual speaker unit has no awareness as such of what voltages or
currents or powers any *other* units experience. It only knows about the
potential between its own terminals, and the current that it then passes.

Sure but if the user is trying to pump a lot of power out of the set,
whatever current that is used by the higher-wattage parallel-pair must
pass through the 80watter which is in series with it. Assuming
identical power dissipation for the moment, the 80watter will blow
before the parallel-pair.

further stressed by the non-linear drive imposed on it by the others.

Are you talking about non-linear impedance here? if so, I'm unsure why. My
own comments on what Steven said were based upon things like frequency
dependence, and linear acoustic effects, not signal-level dependence.

Yes, non-linear impedance (non-linear wrt frequency primarily) whose
effects can be exacerbated at higher levels.

I wish I could suggest a solution but I do not know your goals.

I assume that you mean Steven's goals. :-) My own recommendation to him
would be to avoid using dissimilar speakers in series.

Sorry. I didn't see your name at the top. I agree with your
recommendation.

Kal

On Wed, 29 Oct 2003 16:59:50 +0000 (GMT), Jim Lesurf
wrote:

All current must go through the 80watt speaker which is in series with
the paralleled others.

Erm... Current is not power. They are quite distinct physical quantities,
albeit ones which have a specific relationship for a specific component.

If the 80watter is in series with the others (my interpretation of the
wiring) then all the current passes through it. What power it
dissipates, of course, depends on its own construction.

Thus, it now becomes the limiting power factor,

Afraid that, again, I'm not quite sure why you are saying this. Each
individual speaker unit has no awareness as such of what voltages or
currents or powers any *other* units experience. It only knows about the
potential between its own terminals, and the current that it then passes.

Sure but if the user is trying to pump a lot of power out of the set,
whatever current that is used by the higher-wattage parallel-pair must
pass through the 80watter which is in series with it. Assuming
identical power dissipation for the moment, the 80watter will blow
before the parallel-pair.

further stressed by the non-linear drive imposed on it by the others.

Are you talking about non-linear impedance here? if so, I'm unsure why. My
own comments on what Steven said were based upon things like frequency
dependence, and linear acoustic effects, not signal-level dependence.

Yes, non-linear impedance (non-linear wrt frequency primarily) whose
effects can be exacerbated at higher levels.

I wish I could suggest a solution but I do not know your goals.

I assume that you mean Steven's goals. :-) My own recommendation to him
would be to avoid using dissimilar speakers in series.

Sorry. I didn't see your name at the top. I agree with your
recommendation.

Kal

In article , Kalman Rubinson
wrote:
On Tue, 28 Oct 2003 17:41:53 +0000 (GMT), Jim Lesurf
wrote:

In article , Kalman
Rubinson wrote:
3. The so-called 80watt speaker is in series with the now 100watt
pair and any power disipated goes through both.

Not sure what you mean by the above. Can you clarify?

Just from your wiring.

The wiring was, I think, Steven's, not mine.

All current must go through the 80watt speaker which is in series with
the paralleled others.

Erm... Current is not power. They are quite distinct physical quantities,
albeit ones which have a specific relationship for a specific component.

The current will pass through the '80 watt' speaker, but this does not
necessarily mean that the 'power' passes though the speaker on its way to
the others. This is because the actual power is conveyed by the EM fields,
and the 80 Watt speaker has no way to know what electric potential
('voltage') is across any *other* loads in series with it. Hence it does
not actually experience the power being dissipated by the other units.

Thus, it now becomes the limiting power factor,

Afraid that, again, I'm not quite sure why you are saying this. Each
individual speaker unit has no awareness as such of what voltages or
currents or powers any *other* units experience. It only knows about the
potential between its own terminals, and the current that it then passes.

further stressed by the non-linear drive imposed on it by the others.

Are you talking about non-linear impedance here? if so, I'm unsure why. My
own comments on what Steven said were based upon things like frequency
dependence, and linear acoustic effects, not signal-level dependence.

I wish I could suggest a solution but I do not know your goals.

I assume that you mean Steven's goals. :-) My own recommendation to him
would be to avoid using dissimilar speakers in series.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html