[hassan14a]

Well im abit confused about the dB thing, how do i know what dB im listining to, i mean if my headphones are directly plugged into my computers soundcard im able to see it, but when its plugged in my amp i have no clue about how high the dB is set to.
The maximum volume i listen to is half way up on the volume knob and all the way up in windows. But the usual volume is 1/3 to 1/4

Can anyone help me with this? The amp is heed canamp if that makes a difference.

 

[kuden]

how would u know the dB in the pc ?, i'd imagine that you can't tell it unless you measure it from the headphones since the efficiency of each headphone will be different with the same volume coming from pc.

 

[hassan14a]

I think there is applications out there than can tell you that sort of stuff when you have it plugged in directly to your soundcard, but im not sure though.

 

[lippyjka]

Well I just bought a sound meter of amazon as stories of ear damaged scared me a bit lately

http://www.amazon.co.uk/Sound-Level-...3550106&sr=8-1
I'll post a summary of how well it works when i receive it.

EDIT: there are no applications that will tell you the actual volume coming out of your headphones AFAIK.

 

[gabedamien]

I'd imagine he's probably referring to -dB (minus dB), as in the amount of on-board attenuation set by software volume sliders. Maybe some soundcards have this, just like some amps/receivers indicate volume level by -dB.

Just speculation.

 

[lmilhan]

You need a DB meter to even come close to getting any sort of valid, accurate measurement. You will need to take the measurements close to the headphone earcup, where your ears would normally sit. There is a thread here somewhere on Head-Fi that demonstrates probably the best way to take such a measurement.

If I can dig it up I will post a link.

 

[Balisarda]

I think Kuden's right. Your computer's volume slider doesn't measure decibels, but displays voltage gain as a portion of your sound card's total possible voltage gain. The volume knob on your outboard amplifier works the same way: the farther you turn it, the more voltage gain you get, and the closer you get to your amp's maximum voltage gain.

As Kuden says, the efficiency of headphones (and speakers) varies, so that given a signal input of a certain strength, the output will be higher with higher-efficiency headphones and lower with lower-efficiency headphones.

In acoustics, decibel (dB) measures sound pressure, so the sound pressure your headphones produce depends on the strength of the input signal and the efficiency of the headphones.

Wikipedia defines a decibel as "a dimensionless unit of ratio which is used to express the relationship between a variable quantity and a known reference quantity. . . . The calculation of decibels uses a logarithm to allow very large or very small relations to be represented with a conveniently small number."

What "known reference quantity" is used in acoutics decibel measurements? Wikipedia reports, "the decibel unit is commonly used in acoustics to quantify sound levels relative to some 0 dB reference. Commonly, sound intensities are specified as a sound pressure level (SPL) relative to 20 micropascals (20 µPa) in gases and 1 µPa in other media (standardized in ANSI S1.1-1994).[1] 20 µPa corresponds to the threshold of human hearing (roughly the sound of a mosquito flying 3 m away)."

Pretty neat stuff, even if I never could quite grasp logarithms!

EDIT: I'll be gabedamien is right about the -dB measurement!