[W126 Coupe] Becker & Speakers for sale

[Dan Landiss]

on 9/11/2006 5:10 PM Axel Wulff wrote:

> Reading up on loudness issues, things are a bit more complicated that 
> I remembered. It seems the human ear's sensitivity to different sound 
> pressure levels depends on the frequency of the sound

We used to call that the "Fletcher-Munson" effect. Attempts to 
compensate for that are why some stereos used to have separate "Volume" 
and "Loudness" controls.

> "A widely used "rule of thumb" for the loudness of a particular sound 
> is that the sound must be increased in intensity by a factor of ten 
> for the sound to be perceived as twice as loud. A common way of 
> stating it is that it takes 10 violins to sound twice as loud as one 
> violin. Another way to state the rule is to say that the loudness 
> doubles for every 10 phon increase in the sound loudness level. 
> Although this rule is widely used, it must be emphasized that it is an 
> approximate general statement based upon a great deal of investigation 
> of average human hearing but it is not to be taken as a hard and fast 
> rule."

And even that depends on the nature of the sound. See also:
<http://www.measure.demon.co.uk/Acoustics_Software/db_demo.html>
Remember that the demo uses pure tones, and the ability to perceive 
changes will be substantially less with music.

> So, in order to double the perceived loudness of music (goin from, 
> say, 60 db to 70 db) the amplification power must be 10x (increasing 
> from, say, 3 watt to 30 watt).

I'm afraid so. Other insights might be gained at:
<http://www.acousticalsurfaces.com/articles/noise_reduction.htm>
<http://www.ece.uvic.ca/~aupward/p/demos.htm>

The bottom line is, then, that changing from a 2 ohm speaker to a 4 ohm 
speaker won't make much difference, and then only at full volume.

-- 
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Never argue with a dragon, for you are crunchy and taste good with ketchup.