I have seen some conflicting info and I would just like to confirm that +6dBA is twice the sound level (noise). It makes sense to me because Sound level is the square of the sound amplitude but I have seen many a place saying that this thought is wrong.
thanks
thanks
if the voltage goes up by 2x that's +6db
if the voltage goes down by 1/2 that's -6db
if the power goes up by 2x that's +3db
if the power goes down by 1/2 that's -3db
your ears are logarithmic you need 10x (10db power) to hear 2x as loud volume (depends on frequency) see fletcher/munsen curves wiki
you need 1/10 th power to get to 1/2 as loud
if the voltage goes down by 1/2 that's -6db
if the power goes up by 2x that's +3db
if the power goes down by 1/2 that's -3db
your ears are logarithmic you need 10x (10db power) to hear 2x as loud volume (depends on frequency) see fletcher/munsen curves wiki
you need 1/10 th power to get to 1/2 as loud
You maybe confusing ratio with level. +6dB is a ratio, which is four times the power; other things being equal this also means twice the voltage or twice the sound pressure. +6dbA is a sound level, which is 6dB above the reference level (often 0.02mPa pressure?) and measured using an 'A weighting filter'. A bare dB figure is always expressing a ratio between two numbers. In some cases there may be a standard reference level but this should normally be indicated with a suffix e.g. dBm means dB with respect to 1mW. Unfortunately, sound people often say 6dB when they mean 6dBA.
As multisync says, 6dBA won't sound twice as loud as 0dBA.
As multisync says, 6dBA won't sound twice as loud as 0dBA.
No 3 db is twice the sound pressure level. It is measured in power. Voltage times current is power so if you have a fixed resistance and double either voltage or current you also automatically double the other so you get four times the power or 6 db more.
The rule of thumb (which is inaccurate) is that 3 db is just a perceptible change and a 10 db increase sounds twice as loud.
The rule of thumb (which is inaccurate) is that 3 db is just a perceptible change and a 10 db increase sounds twice as loud.
According to the Australians sound pressure works like voltage, not power. 6dB is twice the sound pressure.
That's nice. Why don't you take a sound level meter and measure any source. Then go to twice the measurement distance and take another reading. Let me know how much the level decreases as you double distance.
Hi,
+6dBA is 4 times the power according to A weighting. 1B or 10dB is x10.
SPL, like voltage levels in equipment, is rated according to the power.
So +3dB in real voltage level (2x) is actually +6dB(4x) in signal level.
+10dB in real voltage level (10x) is actually +20dB(100x) in signal level.
Same goes for SPL, up pressure by x1.4 and SPL doubles i.e. +3dB.
+3dBA is twice the power A weighted.
Its not wrong, that what is says, if you can read.
+6dB SPL is twice the pressure, but not twice the SPL, its 4 times the SPL.
rgds, sreten.
+6dBA is 4 times the power according to A weighting. 1B or 10dB is x10.
SPL, like voltage levels in equipment, is rated according to the power.
So +3dB in real voltage level (2x) is actually +6dB(4x) in signal level.
+10dB in real voltage level (10x) is actually +20dB(100x) in signal level.
Same goes for SPL, up pressure by x1.4 and SPL doubles i.e. +3dB.
+3dBA is twice the power A weighted.
Its not wrong, that what is says, if you can read.
+6dB SPL is twice the pressure, but not twice the SPL, its 4 times the SPL.
rgds, sreten.
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Sreten,
+6dB SPL is twice the pressure, but not twice the SPL, its 4 times the SPL.
I can't see what you mean.
dB is a mathematical way using logs to express a ratio between two values.
SPL means that the second value is a reference level, it is standardised as 20 µPa for 0 dB SPL.
+6 dB SPL expresses the ratio of 2 of a sound pressure of 40 µPa to the reference sound pressure of 20 µPa.
A sound pressure level of +86 dB SPL is 6 dB higher than a sound pressure level of +80 dB SPL.
Expressed in Pa, the first one corresponds to a sound pressure which is twice the sound pressure
of the second.
+6dB SPL is twice the pressure, but not twice the SPL, its 4 times the SPL.
I can't see what you mean.
dB is a mathematical way using logs to express a ratio between two values.
SPL means that the second value is a reference level, it is standardised as 20 µPa for 0 dB SPL.
+6 dB SPL expresses the ratio of 2 of a sound pressure of 40 µPa to the reference sound pressure of 20 µPa.
A sound pressure level of +86 dB SPL is 6 dB higher than a sound pressure level of +80 dB SPL.
Expressed in Pa, the first one corresponds to a sound pressure which is twice the sound pressure
of the second.
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You must be confudled. Combination of two noise sources of equal strength leads to a 3 dB increase, which might be the cause of this widely held misunderstanding. (two noise sources have out of sync components that lead to cancelation)
However, two coincident sources of equal source lead to a 6 dB increase. That is, a doubling of SPL.
Because of the non-linearity of the human ear, you can't just translate a doubling of SPL into a doubling of the loudness level.
Since loudness is stricktly a subjective term, only through testing many individuals, judging whether a 1 Khz tone was either twice as loud or half as loud as another, some approximation has been made for how much SPL difference would be required to achieve this. It is approximately 10 dB SPL difference for a 1000 Hz tone, but this is frequency dependent. Google Robinson and Dadson, or otherwise on Fletcher/ Munson.
vac
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dB's are probably the most often confused topic in audio. Everybody gets it wrong some time or other, or at least assumes something that his listener doesn't. Maybe try it this way:
A Bel is a power ratio of ten. Period. All other uses derive from this. A tenth of a Bel, deciBel, has proven so convenient that it's used everywhere in audio, often with unstated but assumed reference levels changing it, confusingly and incorrectly (if not stated) from a ratio to a quantity. So, note to self: *always* state reference level clearly if not meaning a ratio. Nuf said.
One bit that confuses newcomers is that the number of dB's for voltage is *the same* as the number of dB's for power, at the same impedance. But most always confusions arise from using dB's for quantities and not saying so clearly enough.
So keep it clean, and be safe out there. Arf.
Thanks,
Chris
A Bel is a power ratio of ten. Period. All other uses derive from this. A tenth of a Bel, deciBel, has proven so convenient that it's used everywhere in audio, often with unstated but assumed reference levels changing it, confusingly and incorrectly (if not stated) from a ratio to a quantity. So, note to self: *always* state reference level clearly if not meaning a ratio. Nuf said.
One bit that confuses newcomers is that the number of dB's for voltage is *the same* as the number of dB's for power, at the same impedance. But most always confusions arise from using dB's for quantities and not saying so clearly enough.
So keep it clean, and be safe out there. Arf.
Thanks,
Chris
You must be confudled. Combination of two noise sources of equal strength leads to a 3 dB increase, which might be the cause of this widely held misunderstanding. (two noise sources have out of sync components that lead to cancelation)
However, two coincident sources of equal source lead to a 6 dB increase. That is, a doubling of SPL.
Because of the non-linearity of the human ear, you can't just translate a doubling of SPL into a doubling of the loudness level.
Since loudness is stricktly a subjective term, only through testing many individuals, judging whether a 1 Khz tone was either twice as loud or half as loud as another, some approximation has been made for how much SPL difference would be required to achieve this. It is approximately 10 dB SPL difference for a 1000 Hz tone, but this is frequency dependent. Google Robinson and Dadson, or otherwise on Fletcher/ Munson.
vac
Try it. When two in phase sound sources combine the directional characteristics change. There also is an increase in loading of the sources depending on distance.
a 3 db increase in the SPL requires twice the power to cover the same area. When you double the distance the level from a point source drops by 6 db as it now covers four times the area. With a line array the level drops by 3 db as long as you are still in the near field. That is from the combination action of multiple sources.
6dB is four times the power. -6dB is a quarter of the power. You can get 1/4 power by doubling the free space distance from a source, as the power has to cover 4 times the area. Power always ends up being proportional to the square of something else e.g. voltage, magnetic field.
Confusion can arise when 6dB is also used to describe twice the voltage. This is only strictly correct when the impedance is the same.
Talk of two sources introduces unnecessary complications when people are already confused by the simple situation of one source.
Confusion can arise when 6dB is also used to describe twice the voltage. This is only strictly correct when the impedance is the same.
Talk of two sources introduces unnecessary complications when people are already confused by the simple situation of one source.
Hi,
SPL is not pressure just as levels in studio equipment are not voltage.
Sound Pressure Level describes power, related to pressure squared.
Just as line levels are related to voltage squared (standard 600R load).
+6dB is times 4 as it always will be, its not twice, thats +3dB.
Double pressure and you quadruple power, AKA SPL.
To double SPL multiply pressure x 1.41 AKA root2.
rgds, sreten.
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