Comparing Sensitivities (1 Viewer)

[BillGallagher]

When comparing speaker sensitivity, what's the difference between "Sensitivity," "SPL in Room," and "Anechoic SPL?"

Thanks...

 

[Chu Gai]

Sensitivity, by convention, refers to the voltage sensitivity of the speaker and is taken to mean that 2.83 volts into the speaker will result in a certain SPL a given distance, 1 meter, from the listener. If the speaker happens to have a nominal impedance of 8 ohms, then that 2.83 volts translates into one watt of input power.

In an anechoic chamber or room, there is essentially no sound that is reflected off the walls, ceilings, or floors. Such rooms look similar to this one.


The sensitivity that is given you typically refers to that in an anechoic room and that's just for one speaker. If we add an additional speaker, the total SPL level goes up. If we move into your run of the mill family or living room, the speaker sensitivities go up 2-4, give or take dB due to the fact you now have reflections which augment the direct signal.

Now those values are for one meter distance. If you double the distance, the power drops by a factor of four (inverse square law) and the SPL decreases by 6 dB. You'll find a number of online sites where one can estimate the SPL at a given listening position if one knows the speaker sensitivities. Here is one for example: http://www.myhometheater.homestead.c...alculator.html

 

[RobWil]

Whoa! Professor Chu! Great post in very simple and easy to understand terms!
BTW, is that your room?

 

[ScottCHI]

love that floor