Decibels are not quantities of anything, not even sound.They are the ratio between 2 different levels of power.Bels(in this case) are the relationship between amplitude and energy, decibels are 1/10th of a Bel.Bels are logarithmic, and its complicated even further by the fact human hearing is logarithmic as well.

3 dB = double the intensity
10 dB = ten times the intensity, but twice the perceived sound level

In terms of amps and speakers:
2X the amplified power = 3 dB
2X the speakers = 6 dB
2X the perceived loudness = 10 dB

Engines:
2X the horsepower = 3 dB
4X the engines = 6 dB
10x the horsepower = 10 dB

difference between 100 dB and 200 dB = 10x10x10x10x10x10x10x10x10x10 or 10 billion times the intensity=2x2x2x2x2x2x2x2x2x2 or 1024 times the perceived loudness

anyone have a spare brain?

ya I'm lost also

You really don't need to understand it.If you ever needed to figure out dB(I don't know why you would), just get a calculator that has a Log(arithm) function.The log of 2(2X power) is .301, which is in Bels, so in dB it's 3.01(commonly refered to as 3 dB).Log of 3 is .477 or 4.77 dB.Log of 4 is .602 or 6.02 dB.Log of 10 is 1 or 10 dB.

In terms of human sound perception, it takes 10 times the sound output, for us to perceive it as a 2X increase.

I remember just a bit of this shit from my loud stereo days 10 years ago.

how is the standalone coming?
LOL!

Thanks for clrearing that up, Eric.

It appears we've weeded out the intellectuals from the dumbasses. ;)

speak for yourself Mat!

i am still not weeded out!

-E

At least you got the title of the thread correct ;)

Yep, I admit it, I'm a nerd.But it's OK, because the chicks still dig me

:ohmy: you have way to much time on your hands! ;)

I wish that was the case.

LMFAO I wish i did 2!!!

I wish that was the case. [/b][/quote]
You would if you weren't always sleeping or "napping" :slap:

We use dB reading everyday when reading the power out of our transmitter on our radar. I don't go as far as breaking it down to all that shit cuz that's a little past me. All I know is that if we up the dB by 3 we double our power output. I don't know insane specifics. Guess that's why I'm a tech and not an engineer.

Hey there Mensa how do you ever learn this shit, if your sleeping 98% of the day?

<!--QuoteBegin-Enes@Aug 18 2004, 11:56 AM
anyone have a spare brain?[/quote]
That comment weeded yourself out. :lol:

The past couple weeks my cable modem was randomly losing connection. A tech came out, changed a cable and a splitter, and the signal went from -15db to -9db, a gain of 6. My connection has never been better.

you are correct except for this. this is a subjective statement. what one person describes as twice as loud might not be twice as loud to another person.


anyway, in the other thread, i might not have said it right, but what i meant with 6 db was pressure. double the power is +3db, double the pressure is +6db. sorry.

ya that 6dB gain shoulda quadrupalled the power of whatever signal was coming through there. Prolly why you gotta super connection now!! Our radars output is at about 46dB

Kinda true and very pointless.While there is a standardized pressure for 1 dB, in general, the way we use dB to describe SPL is a relative scale, where 1 dB is the thresold of human perception.

If you want to get technical, there is no way to quantify perception, so there is no way for a person to know if one sound is actually twice as loud as another(by perception alone).

If you want to get really technical, all perception is subjective.Take the color red for instance.We have been taught when we see light at a certain wavelength, its the color red.But red in your eyes is likely different from red in my eyes, since we are 2 different people with 2 different brains.Since I can never see with your eyes or hear with your ears, what I would describe as red, may not be exactly what you would describe as red.

So in general and for all practical purposes 10dB = 2x the perceived sound.

How would one go about "describing a color" anyhow?

It was just an example to prove a point, which is all perceptions are truely unique to the brain perceiveing them.

0 db, right? that is what you meant?

No, he meant 1db. 1db is the smallest change in volume that a human can perceive.

Since were talking about perception, why not throw this baby out there.

dBA(A-Weighted dB) scale?

Fletcher munson curve aka, equal loudness curve.

Ahh.

OMG MY HEAD IS GOING TO BLOW!!!

way too much info!!!

lol. i could go into why that is wrong, but i won't. this thread is fun.

I'd like to hear why that is wrong, so feel free to explain.