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

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 !

In 55 years, I've never blown a tweeter or speaker.  I've used 16 watt Sherwood S7100 receiver to 200/400 watt hybrid Counterpoint amps.  Electrostats and dynamic speakers.   My 35 watt voltage regulated highly modified Dynaco ST70 lacks the watts to really exploit my Legacy Focus 6-12" woofers and provide ultra resolving sound as my 125 watt custom monoblocks but they have the same sound signature.  It takes a lot of watts to increase 3db of sound, especially for low impedance, inefficient speakers.  I match the amp to the speaker and don't worry about loudness (my current listening rooms can go above 110db clean and easily but that's more than I want or need).  

It’s all about Appalachian mountains versus the Rocky Mountains when it comes to frequency definition.

The ability of ears to differentiate between all those pressures circulating via sound waves, or pressure amplitudes, is truly remarkable. So the more precise those waves can be transferred from speakers the better it should sound.  And somehow higher wattage delivered through higher quality amplifiers is really helpful and so difficult to explain.  I guess a lot has to do with how quick an amplifier responds to all those frequencies in terms of making sure that all the power demands are spread to reproduce all those frequencies in an incredibly fast manner with very low distortion.

Someone on Audiogon posted about an ASR review of a 10 watt Luxman tube amp by Amir. He used an inefficient speaker to test how it sounded. What a joke. Three ASR posters Ken Tajalli said the Luxman tested as defective and should have been returned/testing was unreliable. Robaroni said the amp is pleasant to listen to DonDish and Robaroni seconded my opinion that Amir should have used an efficient speaker as this is a low power amp which it was made for. So, matching a working condition amp to a speaker is foremost to truly hearing the amp as well as speaker. (Amir said it is ALL in the bench test results-this time of a defective amp-ha ha).