Loudness

[Jiro]

What property constitutes the loudness of sound?

What would you want to get to efficiently gain more loudness?
I just did a calc and found that from a distance or 3.5 meters away from a 250W speaker vs 40W speaker is only like 8dB!!! thats a huge increase in wattage... hmmm what if i want to double the loudness?!

 

[coldtrain]

10x the power...

 

[Petebass]

Your post raised many questions but before I ask them, can you runs us through how you conducted the experiment.

 

[geshel]

I'm impressed. The difference between 250w and 40w is almost exactly 8dB, so that is exactly what you should have measured.

dB = 10 * log (P1 / P2)

 

[geshel]

P.S. The "loudness" of sound is due to pressure -- the pressure variation caused by the compression / decompression of air that is a sound wave.

 

[Jiro]

Ya it was straight out of my physics text book. There was no experiment involved... it was all theoretical.

 

[Jiro]

looks like if i want to double my volume from 200W which outputs 99dB... Ill need to increase my wattage to 1687983077600Watts with final output 198.526dB.

Just to use as a reference point. Jet Plane at 30m has a sound level of 140dB. This calculation was done from 3.5 meters away from the source.

 

[Tim__x]

You don't need that much power, I mean, I've heard of headroom but...

Seriously though, 6-10db sounds twice as loud, just as decibels are logarithmic our hearing is too (approximately).

 

[Jiro]

ooops! hahaha
"Sound levels of around 200 dB can cause death to humans"

 

[seanm]

looks like if i want to double my volume from 200W which outputs 99dB... Ill need to increase my wattage to 1687983077600Watts with final output 198.526dB.

Just to use as a reference point. Jet Plane at 30m has a sound level of 140dB. This calculation was done from 3.5 meters away from the source.

No, to double the volume you need 10x the power. So you replace the 200W amp with a 2000W amp.

 

[geshel]

Right -- 10 dB more sounds roughly "twice as loud" to people. 10dB takes 10x the power.

You get much more "bang for the buck" by

a) finding more efficient speakers, and

b) using more speakers

I'm not saying more power isn't good. But it's not uncommon for there to be 3 or 6 dB difference between the efficiency of bass cabs out there. That means one will be as loud with only half or a quarter of the power. Of course, there are tradeoffs (size/weight, and frequency response). And doubling the number of speakers typically adds about 3dB more efficiency for bass.

 

[IvanMike]

man, i so want an amp with 1.7 Trillion watts.

 

[Tim__x]

...and a nuclear power plant to go with it?

 

[Joe Beets]

I'll tell you what constitutes the loudness of sound. It's when the low frequencies from your bass make one guitar player throw up his dinner on stage and the other one craps his pants.

 

[Happy MurphDay]

I'll tell you what constitutes the loudness of sound. It's when the low frequencies from your bass make one guitar player throw up his dinner on stage and the other one craps his pants.

I believe south park references that as "the brown note"