Impact noises & hearing thresholds

[shaunnutley]

If somebody is moderately deaf with a hearing threshold of 50dB and they cannot hear a dog barking at 50ft away which is 80dB, will they also not hear a 80dB impact noise from the bang of a door also at 50ft away? The pitches of both noises are within the pitches of the person's hearing threshold. I The decibel levels i give are taken about a metre away from the sound source and the person is standing outdoors. Take it to be that there are no other effects on the sound.

[mibn2cweus]

The barking dog would probably better represent a point source from which a reference db level could be measured at one metre. Much of the acoustic energy from a banging door would conduct into surrounding materials and therefore emanate from a broader area making it more difficult to obtain a reference level. You need also take into consideration frequency and pulse profiles when considering how these sounds are perceived by the human ear and depending on the weighing used by the meter the difference in how it responds to pulses and more continuous sounds will alter the readings given.

I hope you still have your text book because you would most likely be better served by reading and assimilating it more thoroughly than by applying the �information� your getting from me. I am not a audiologist.

[tubeway]

A good answer from mibn2cweus. Especially the point that it depends what weighting is used on the dB scale. Hearing thresholds are measured using dB(HL), while noise is measured using a different scale such as dB(A). So this will cause some inconsistencies too.

It has been some years since I studied - but I am an audiologist.