Hi,

I am wondering if there is a good way of calculating a speaker's dB(SPL) at a certain volume level if you know the its rms voltage/current/power?

Other factors would also be speaker diameter and distance from which observer is listening from but I'm curious as I don't really want to by an SPL meter if it's not necessary.

Cheers,
JP

 

The datasheet of a speaker spec's its SPL so there is not much to calculate but its power and distance.

The size of the magnet and the smallness of the gap between the moving voice coil and the magnet assembly affect the sensitivity of a speaker.

Some cheap speakers produce a high SPL at only one frequency and many hifi speakers produce a lower SPL at all frequencies.

A cheap speaker focusses higher frequencies into a narrow beam. A good speaker has a wide angle for most frequencies.

 

An example of a speaker sensitivity spec would be 90db@1watt/1meter.

To calculate SPL for increased power you add 3db every time you double the power at the same 1 meter distance. The speaker would produce 93db with 2 watts, 96db with 4 watts etc..

To calculate SPL for increased distance you subtract 6db every time you double the distance from the speaker.

 

Hello,

Does this help?
http://www.sengpielaudio.com/calculator-soundlevel.htm

It is a link from this page:
http://www.sengpielaudio.com/Calculations03.htm

Bertus