Bob Mannix wrote:
"Arfa Daily" wrote in message
...
"Bob Mannix" wrote in message
...
"Dave" wrote in message
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Hi all.
I'm sorry if this seems OT but I hope someone can still help.
Anyone know how to convert EIAJ into RMS values?
Say if you have an amplifier stating as having 230W EIAJ power, any idea
what that might be in RMS?
I've tried Googling but nothing of sense comes up.
Cheers in advance.
Wavey Dave
It depends on the voltage range, I guess, as it's defined as follows:

Maximum EIAJ standard test output power: average of RMS output voltage
squared divided by load impedance.

Don't know what the test conditions are for this though. Probably safe to
say roughly the same as RMS power depending on how you drive it.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)


Who on earth comes up with this stuff ? I'm sure it must have made some
sense to the person at the time, but dear me, average of RMS ? Squared ?
Divided by load impedance ? Should it also have "multiplied by the outside
air temperature and divided by the number of channels cubed, minus the
number you first thought of" in there as well ... ?


Well, why I'm not sure, but calculating power as voltage squared over
impedance is perfectly reasonable and no cause to bring in the air
temperature! It's some sort of average that takes into account the dynamic
voltage range of the system. Not that I care, but someone might.

As to the loudness of speakers, efficient speakers are loud and low quality, \
Not necssarily.

high quality speakers are inefficient and quieter (generally speaking) so
you make your choice. Notting Hill Carnival sound system, go for efficiency
and b*gg*r the fidelity, you want to rattle windows, Self absorbed, anally
retentive, solo, esoteric hi-fi listening, low efficiency speakers and big
amps ;o) !


Best speakers we used in my time making rigs, were JBL horn copies by
DAS About 110dB/watt.

Those and bullet horn tweeters covered about 800Hz upwards very very
well. superb low distortion a but the frequency response had a few
little peaks in it.

IIRC we used 8 or 12 inch units at around 92-95dB/watt - massive magnets
on em.

And twin 15" or a single 18" unit to go up to 200hz or so in reflex
cabs. Us of lighweigght foam composite cones and BIG magnets gets a very
decent efficiency out of even those.

What you are thinking of is crappo hifi. Its easy enough to take a
poorly damped speaker and strangle it to get a flattish reponse, and
people want '100W speakers' not 'speakers capable of doing 120db SPL'.
It sounds ok, its just chap. My DAS studio monitors were massively more
efficient. Sadly they have decoiled and need a recone..after 25 yars..



Or if its loud you want, cheap magnet, ultra thin paper cone, a
celestion! and into a box..and hey folks, its the Vox AC30!! a very good
soundboard for an electric guitar, with multiple interesting resonances
and fed from a ovrdriven 100 ohm impedance valve amp with all negative
feedback removed for gain!. You cant get better than that ;-)

Loud, for 30watts..