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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

Showing 1 response by clearthinker

clearthinker's avatar
clearthinker
1,582 posts
 

@anotherbob        Don't get taken in by this pseudo science.  It is a con.  There is no system that can instantaneously increase power.  Musical transients are gone by the time the power is produced.

Krell started this when they wanted to appear greener.  They stopped making pure Class A amps for which they had been rightly applauded and said their new amps could increase power instantly so that transients could still be correctly reproduced.

Further, such a system might not reproduce music consistently because the watt or two that suffices most of the time would not sound the same as 100 or 200 watts suddenly introduced by the amp.  I don't have such an amp but I wonder if anyone has noted this.

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