Re: Speaker impedances

["Donald E. Simanek" <dsimanek@eagle.lhup.edu>]

On Thu, 12 Jun 1997, brian whatcott wrote:

> At 15:57 6/11/97 -0800, you wrote:
> > > Use an ohm meter to get a dc resistance. Multiply this resistance by
> > > 1.333333333333. It will give you the approximate impedance of the driver.
> >
> > ... or save yourself some button pushing and just use "1.3"; this will
> > still give a pretty good "approximation."    ;-)
> > ...
> > A. John Mallinckrodt 
>
> I saw the very natural reflex to curb unnecessary precision
> which does not contribute to accuracy here.
>
>    But then I had a treacherous thought.
> If the suggestion had been couched as
> "multiply the resistance by 4/3" the approximate nature
> of the suggestion would be clear - yet its decimal equivalent 
> seems quite out of place.

I may have missed it, but I haven't seen anyone inquire about the really
important matter here. What is the origin of that number 4/3 or whatever?
What's the theory behind it, and what value comes from theory? Which is
the approximation, 4/3, or 1.33 ? Even more important: why? We shouldn't
use "rules of thumb" unless we know more about the thumb.

	-- Donald

......................................................................
Dr. Donald E. Simanek                            Office: 717-893-2079
Prof. of Physics                    Internet: dsimanek@eagle.lhup.edu
Lock Haven University, Lock Haven, PA. 17745          CIS: 73147,2166 
Home page: http://www.lhup.edu/~dsimanek            FAX: 717-893-2047
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