From: Robert Baer
X-Mailer: Mozilla 4.75 [en] (Win98; U)
Subject: Re: wattage meter exists??
Date: Sat, 07 Sep 2002 07:38:47 GMT
NNTP-Posting-Date: Sat, 07 Sep 2002 00:38:47 PDT
Organization: EarthLink Inc. -- http://www.EarthLink.net
John Woodgate wrote:
> I read in sci.electronics.design that Bob Wilson pam.bc.ca> wrote (in ) about 'wattage
> meter exists??', on Fri, 6 Sep 2002:
> >In article <firstname.lastname@example.org>,
> >email@example.com says...
> >>Hi! Is there any device such a wattage meter that exist?
> >>How much and where?
> >Of course there is! I have a nice one that reads accurately both real power
> >(wattage) and apparent power, from nearly DC to well above 100HKz. More
> >standard ones that work at line frequency have been around for almost
> Yes, but will it measure the 'wattage' of the sound from a 650 W PMPO
> computer sound system? (;-) We don't quite know what the OP has in mind.
> Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
> Interested in professional sound reinforcement and distribution? Then go to
> PLEASE do NOT copy news posts to me by E-MAIL!
Well, if all one wants is an estimate of power out of a sound system
(and that is all that is done to get those "specifications" and
sometimes less), then use a resistive load of the proper impedance (eg:
8 ohms, 16 ohms, whatever the speakers or headphones are supposed ot be)
and measure the voltage across each resistor at the specified inoput
drive level; usually 1Khz is used, but 440Hz is OK also, as power levels
are almost never guaranteed over a specified frequency range.
Usually a frequency response is given with no directly stated link to
the power level specified, and power level is just that - with no
frequency involved at all.
There is a lot of stupidity and false implications involved with most
"specifications" of audio amplifiers made to drive speakers and/or
There have been some exceptions to this generality, but the makers of
that equipment had a lot of integrity and really cared about their
products and customers.
Virtually all audio stuff made for computers is cheap crap, some that
seems to work well, but junk nonetheless.