Pulse sounds and Ear muffs

[shaunnutley]

I recently bought a pair of ear muffs and on the packaging it states the real-ear attenuation data was obtained using a continous sound and pulse sounds might produce different attenuation data. Why is this?

My only guess is that the pulse sound might be more distinguishable, hence probably giving a lower reading at certain frequencies. Does anyone know the answer to this?

[mibn2cweus]

If there were one hundred candles burning behind a screen and I blew one out you would probably not notice the difference whereas if I blew them all out at once this would be much more obvious.

Set an FM receiver to a blank station so that there is a steady white noise coming through the speaker. Now quickly switch it back and forth between FM and CD with no CD playing. This should give you an approximation between a continuous sound and a pulse. These two particular types of sound would probably not alter the attenuation of the ear muffs alone however the mind is stimulated much more by sudden changes in the perceptual field than by steady stimulation.

For a continuous sine wave tone the sound pressure undergoes smoothly progressive changes. This is not the case for a square wave (pulsing) tone of similar average acoustic energy. Sudden changes in the sound pressure associated with a pulse may be more likely to mechanically penetrate the muting materials in an ear muff.

How the ear muffs react to sudden exposure to pulsing energy along with the properties of human perception my reduce the effective muting properties of the combined system.