To Dick Pierce - Power Input

Archived from groups: rec.audio.tech (More info?)

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

Archived from groups: rec.audio.tech (More info?)

Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote in
news:4177218D.252B55C3@hotmail.com:

>
>
> 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.

Archived from groups: rec.audio.tech (More info?)

Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote in
news:417841E0.1EC44F37@hotmail.com:

>
>
> "Rich.Andrews" wrote:
>
>> Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote in
>> news:4177218D.252B55C3@hotmail.com:
>>
>>
>> > 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.

Archived from groups: rec.audio.tech (More info?)

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 *
*******************************************

Archived from groups: rec.audio.tech (More info?)

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:417F0AB8.278AB4C0@hotmail.com...
> 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.