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Perception and Watts: Doubling of power

There's a curious rule of thumb, which to my ears seems mostly true:

  • To double the perceived volume, you must output 10x more power.

10x power = 10 dB by the way.  We've read this as we were buying amps and trying to decide between 100w/channel and 150w/channel.  We are told, repeatedly that 50 W difference isn't really that much.

On more than one occasion I've tested this and found it's pretty much spot on.  Here's my question:

How can any of us really tell what half as loud, or twice as loud is?

I mean, think about this for a bit.  I cannot tell half as bright, or twice as bright, but it seems I actually CAN tell what half as loud is.  How does this even begin to work in the ear/brain mechanism?? 😁

erik_squires
elliottbnewcombjr
5,243 posts
 

buy a spl meter!

 

fuzztone's avatar
fuzztone
5,508 posts
 

And why does this possibly matter in the pursuit of musical enjoyment?

johnnycamp5's avatar
johnnycamp5
122 posts
 

Perhaps because it has been repeatedly proven in human testing that an increase in DB (loudness) is perceived as music “sounding better”

gs5556
1,218 posts
 

Different frequencies consume different power so "twice as loud" would be frequency dependent in many cases. Paying for an additional 50 watts will improve low frequency performance -- you may not hear it louder but you will hear it cleaner with respect to transients and lower distortion from better controlling the woofer. It gets integrated into the music a little better.

fuzztone's avatar
fuzztone
5,508 posts
 

"Scientific tests show that we can hear and accurately detect very tiny differences in loudness (1/4 dB is possible)."

Twice as loud as optimum is noise not music. Like a demo in the Grado room.

 

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