Perception and Watts: Doubling of power

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

Using music as a test signal for determining half or twice loudness is indeed difficult. Music varies in pitch and loudness and so is a moving target. The bel scale was developed by Bell Labs using steady tones on multiple test subjects and determining an average estimation of half or twice as loud. The difference in acoustic pressure called a bel. Decibel, of course being 1/10 of a bel. So a bel is what the average human perceives as twice of half as loud.

The actual acoustic pressure between the threshold of hearing and the threshold of pain is more than a million to one. The human ear/brain compresses this range in a logarithmic manor so as to be manageable. This is why the objective acoustic power must be increased by 10x to be perceived as twice as loud.

To answer the original question: there is generally no reason for us to worry about what is half of twice as loud. But, it is good to understand that a 200 W amp will only play 3db (21.9%) louder before clipping than a 100 W amp.  

I believe a 3db increase in volume is perceived as twice as loud, not 10x power....that is what I’ve always read...anyhow..

https://www.logison.com/blog-article_/17588/blog-entry-19256/sometimes-change-isntgood#:~:text=A%203%20dB%20change%20yields,a%2023%25%20increase%20in%20loudness.

audioguy, with respect, I believe you are mis-reading things. "A 3 dB change yields a 100% increase in sound energy and just over a 23% increase in loudness." (from the article you included). 3dB is indeed a doubling of actual acoustic energy as measured in millibars of atmospheric pressure change. "Loudness" refers to what humans perceive as volume change. A doubling of amp power or acoustic energy is perceived by humans as around 23% louder.

"Louder is better, David. In this universe louder is better" Jerry Garcia to David Grisman

@audioguy85  I believe @hertzhead  has correctly explained the issue.

3 dB corresponds to 2x the voltage at the speaker terminals, but we do not actually hear it as twice as loud.  We hear it as a noticeable increase, but not twice.  You can try this yourself with an SPL meter.  Use a test tone and try increasing/decreasing by 3 dB. 

small speakers. use 650W monos.

amazing presence, air, and overall sound.

i can't get any louder, as speakers would explode.

motorhead, tank, anti nowhere league, detente, dark angel, GBH, exploited, pestilence, Y&T, Venom, sound SOOOOOOOOOO much better at max volume!

power is your friend, never have i clipped the amps, never have i ever heard any slight dip in sound, nothing but constant bombardment of russ andersons vocals as clear as if he was in my room.

this is what power gives you, no slowing down, no muddy anything, just pure bliss never any restraint, or sound of of straining, what so ever. sure bigger speakers would benefit (as would I) from power, but the ones I want are much to much for me, hell, the speakers i would love, are 2-3 Xmore than my truck and suv combined. 

we must make do with what we have.

enjoy the tunes!

Metal is a lifestyle !