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Northstar
 
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Default To Dick Pierce - Power Input

In 1972 Small (JAES) defined power input to a loudspeaker system as
that delivered to a resistor with the same value as the voice coil
resistance. IOW as the DC resistance of the coil. Do you know if
this has been standardized or adapted by the industry? TIA

ns


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Pooh Bear
 
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Northstar wrote:

In 1972 Small (JAES) defined power input to a loudspeaker system as
that delivered to a resistor with the same value as the voice coil
resistance. IOW as the DC resistance of the coil. Do you know if
this has been standardized or adapted by the industry? TIA


AES has adopted same AFAIK so that 1 watt in 8 ohms ( nominal impedance
speaker ) is now specified as 2.83V at the speaker terminals for
example.


Graham.

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Rich.Andrews
 
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Pooh Bear wrote in
:



Northstar wrote:

In 1972 Small (JAES) defined power input to a loudspeaker system as
that delivered to a resistor with the same value as the voice coil
resistance. IOW as the DC resistance of the coil. Do you know if
this has been standardized or adapted by the industry? TIA


AES has adopted same AFAIK so that 1 watt in 8 ohms ( nominal impedance
speaker ) is now specified as 2.83V at the speaker terminals for
example.


Graham.



2.83 volts is 1 watt into an 8 ohm load. For some strange reason most
speakers are 4 ohms but the manufacturers still use that same 2.83 volts
which translates to 2 watts, thus improving their speakers rated
sensitivity by 3 db.

r



--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.


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Pooh Bear
 
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"Rich.Andrews" wrote:

Pooh Bear wrote in
:


Northstar wrote:

In 1972 Small (JAES) defined power input to a loudspeaker system as
that delivered to a resistor with the same value as the voice coil
resistance. IOW as the DC resistance of the coil. Do you know if
this has been standardized or adapted by the industry? TIA


AES has adopted same AFAIK so that 1 watt in 8 ohms ( nominal impedance
speaker ) is now specified as 2.83V at the speaker terminals for
example.


Graham.



2.83 volts is 1 watt into an 8 ohm load. For some strange reason most
speakers are 4 ohms but the manufacturers still use that same 2.83 volts
which translates to 2 watts, thus improving their speakers rated
sensitivity by 3 db.


I've heard of this cheat. I don't think that reputable manufacturers use it.

Actually, most speakers are still 8 ohms IME.


Graham



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Rich.Andrews
 
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Pooh Bear wrote in
:



"Rich.Andrews" wrote:

Pooh Bear wrote in
:


Northstar wrote:

In 1972 Small (JAES) defined power input to a loudspeaker system as
that delivered to a resistor with the same value as the voice coil
resistance. IOW as the DC resistance of the coil. Do you know if
this has been standardized or adapted by the industry? TIA

AES has adopted same AFAIK so that 1 watt in 8 ohms ( nominal

impedance
speaker ) is now specified as 2.83V at the speaker terminals for
example.


Graham.



2.83 volts is 1 watt into an 8 ohm load. For some strange reason most
speakers are 4 ohms but the manufacturers still use that same 2.83

volts
which translates to 2 watts, thus improving their speakers rated
sensitivity by 3 db.


I've heard of this cheat. I don't think that reputable manufacturers use

it.

Actually, most speakers are still 8 ohms IME.


Graham





Graham,

It has been my experience that most new speakers are of the 4 ohm variety.
I could be wrong but I don't think so.

r


--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.




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TonyP
 
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"Pooh Bear" wrote in message
...
2.83 volts is 1 watt into an 8 ohm load. For some strange reason most
speakers are 4 ohms but the manufacturers still use that same 2.83 volts
which translates to 2 watts, thus improving their speakers rated
sensitivity by 3 db.


I've heard of this cheat. I don't think that reputable manufacturers use

it.
Actually, most speakers are still 8 ohms IME.


IME the reverse is true. The majority of HiFi speakers are now 4-6 ohms, and
the majority of manufacturers quote sensitivity for 2.83V, if they state a
figure at all.

Since the impedance curve of most speakers is far from flat, specifying an
input voltage is just admitting the reality of what was usually done anyway,
even if it was mislabelled as 1 watt.

TonyP.


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Peter Larsen
 
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Default

Pooh Bear wrote:

2.83 volts is 1 watt into an 8 ohm load. For some strange
reason most speakers are 4 ohms but the manufacturers still
use that same 2.83 volts which translates to 2 watts, thus
improving their speakers rated sensitivity by 3 db.


It is not totally unfair, most poweramps do in my understanding deliver
the same output voltage in 4 as in 8 Ohms under normal, non-clipped use.
It could equally well be described as mispresentation of the facts to
not use the same voltage for both impedances.

Fairness or cheat gets to be a matter of exactly what wording they use
and whether sensitivity is described as a voltage or a power
sensitivity. That said, if it is a voltage sensitivity that is specified
then it should be _obvius_ that so is the case and what the implications
are.

Graham



Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************


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Pooh Bear
 
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"Rich.Andrews" wrote:

It has been my experience that most new speakers are of the 4 ohm variety.
I could be wrong but I don't think so.


Seems to depend on the market sector.

Pro speakers tend to be 8 ohm as default, although 4 and even 16 ohm variants
may be offered too.

All the hi-fi speakers I've met have also been 8 ohm. Maybe the drive to low
cost pretty boxes has resulted in more use of lower impedance types ?


Graham

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TonyP
 
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"Pooh Bear" wrote in message
...
All the hi-fi speakers I've met have also been 8 ohm. Maybe the drive to

low
cost pretty boxes has resulted in more use of lower impedance types ?


The biggest reason for the shift to 4 ohm IMO, is the wide spread use of 2
small bass/mid drivers per box instead of one larger one.
Mostly they wire two 8 ohm drivers in parallel, and get a nominal 4 ohm box.
The real impedance varies with frequency as always.
Very few manufacturers make 16 ohm drivers any more, so using two of those
in parallel is not a viable option to most box builders.
Also the fact that many amplifiers can deliver more power into 4 ohms than
8, is a benefit in most cases.

TonyP.


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Peter Larsen
 
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Default

Pooh Bear wrote:

All the hi-fi speakers I've met have also been 8 ohm. Maybe
the drive to low cost pretty boxes has resulted in more use
of lower impedance types ?


It appears that some manufacturers, example: Cambridge p500, prefer to
spec power in a somewhat lowish impedance - ie. 6 Ohms, no mentioning of
number of channels driven. The danish importer then quotes that loosely
worded power spec as the power spec for 8 Ohms ...

Graham



Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************
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