#1

I am confuseed about volume and dB

I know that 100W is twice as loud as the same 10W ( with EVERYTHING else the same )

but 93dB is twice as loud as 90dB, right? or am i soo wrong?

If i am wrong, please tell

Thanks in advance

I really sound like a noob now

I know that 100W is twice as loud as the same 10W ( with EVERYTHING else the same )

but 93dB is twice as loud as 90dB, right? or am i soo wrong?

If i am wrong, please tell

Thanks in advance

I really sound like a noob now

#2

Both of your statements are correct. The link you're missing is that the wattage to dB relationship is logarithmic so that you need 10 times the power to get twice the volume. You'll find that your math lines up that way.

So you get: 10 watt amp at 90 dB is half as loud as 100 watt amp at 93 dB,

Which is correct. One problem is that your ears are really bad at hearing "twice as loud" so saying that isn't really useful.

Another issue is that dB is a measurement at a certain point - you know, of course, that an amp isn't as loud at 6 feet as it is at 3. That is an inverse relationship, such that the dB at 3 feet is not three times quieter than at 9 feet - it's 9dB quieter, or 8 times quieter. A further issue is that speaker sensitivity comes into play a lot more than people tend to be aware of.

This is confusing, complicated stuff, to be sure.

So you get: 10 watt amp at 90 dB is half as loud as 100 watt amp at 93 dB,

Which is correct. One problem is that your ears are really bad at hearing "twice as loud" so saying that isn't really useful.

Another issue is that dB is a measurement at a certain point - you know, of course, that an amp isn't as loud at 6 feet as it is at 3. That is an inverse relationship, such that the dB at 3 feet is not three times quieter than at 9 feet - it's 9dB quieter, or 8 times quieter. A further issue is that speaker sensitivity comes into play a lot more than people tend to be aware of.

This is confusing, complicated stuff, to be sure.

#3

If i had a 20w and a 40w , how much (percentage) louder is that?

#4

Both of your statements are correct. The link you're missing is that the wattage to dB relationship is logarithmic so that you need 10 times the power to get twice the volume. You'll find that your math lines up that way.

So you get: 10 watt amp at 90 dB is half as loud as 100 watt amp at 93 dB,

Which is correct. One problem is that your ears are really bad at hearing "twice as loud" so saying that isn't really useful.

Another issue is that dB is a measurement at a certain point - you know, of course, that an amp isn't as loud at 6 feet as it is at 3. That is an inverse relationship, such that the dB at 3 feet is not three times quieter than at 9 feet - it's 9dB quieter, or 8 times quieter. A further issue is that speaker sensitivity comes into play a lot more than people tend to be aware of. For example, a 97dB greenback in a 100 watt amp will actually be the same volume (theoretically; in practice, efficiency and a number of other factors keep it from being perfect) as a 10 watt amp through a 100dB Vintage 30.

This is confusing, complicated stuff, to be sure.

but when people say: ah, the difference is just 3dB, that's not much!

that statement is wrong, cuz it's half the volume, right?

#5

Here's the formula for calculating dB from wattage, assuming all other variables are equal:

2^ (log10( Larger/Smaller)) is the ratio, multiply by 100 to get the percent.

So for your 20 and 40 watt,

2^(log10(40/20) = 2^log10(2) = 1.23, or 23% louder.

When do people say that? Most times, 3dB gets thrown around when people think that removing a speaker lowers the volume by that much - which it doesn't, which is why people think 3dB isn't much, because they can't hear the difference in volume between 1 and 2 speakers, because there isn't one. So your premise that 'people say 3dB isn't that much' seems flawed to me, because I've only heard it to refer to the erroneous notion that it's the difference between 1 and 2 speakers.

Anyway, yes, 3dB is a significant volume increase, but even though it's 'twice as loud' it doesn't really sound like that to your ears. Conversation volumes can easily range 3-6 dB, but you don't really notice that some parts are "four times as loud" because that's not how you perceive sound. I'd say that 3dB is probably noticeable, but at loud amp volumes, it is a whole lot less than you think it is. It's twice as loud on paper but it's perhaps the difference between a single coil and a humbucker on the same amp.

2^ (log10( Larger/Smaller)) is the ratio, multiply by 100 to get the percent.

So for your 20 and 40 watt,

2^(log10(40/20) = 2^log10(2) = 1.23, or 23% louder.

but when people say: ah, the difference is just 3dB, that's not much!

that statement is wrong, cuz it's half the volume, right?

When do people say that? Most times, 3dB gets thrown around when people think that removing a speaker lowers the volume by that much - which it doesn't, which is why people think 3dB isn't much, because they can't hear the difference in volume between 1 and 2 speakers, because there isn't one. So your premise that 'people say 3dB isn't that much' seems flawed to me, because I've only heard it to refer to the erroneous notion that it's the difference between 1 and 2 speakers.

Anyway, yes, 3dB is a significant volume increase, but even though it's 'twice as loud' it doesn't really sound like that to your ears. Conversation volumes can easily range 3-6 dB, but you don't really notice that some parts are "four times as loud" because that's not how you perceive sound. I'd say that 3dB is probably noticeable, but at loud amp volumes, it is a whole lot less than you think it is. It's twice as loud on paper but it's perhaps the difference between a single coil and a humbucker on the same amp.

#6

twice as loud is 10db. 3db is minimun of difference perception.

#7

My mistake. The math still lines up. I think that 1 dB is the minimum perceptible difference, though.

#8

okay, thanks for all the information ^^