jaddie
Account deactivated by request.
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- Mar 28, 2011
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No, I'm not confusing anything, I do understand the difference between audibility, perceived loudness and measurement for safety. We've sort of been talking around the issue, and I think we actually both do understand and are in agreement on much of this.
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Agreed with all.
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I believe I've already said pretty much that in another post. We use it because its the standard, right or wrong, its the standard.
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No, not so much perceived loudness as SPL. It may in some sense be better than the A curve at 100dB SPL, but still not quite right.
So, perhaps we might agree on these:
A Weighting was designed for low (speech level and below) noise measurements, based on old equal loudness curves that have since been updated.
A-weighting is the standard for measurement of high level noise exposure related to safety issues and hearing damage.
A-weighting may not be appropriate for use when perceived loudness above 40 phons is required, but again, is a standard and used all the time. So it must also be used that way.
A-weighting would be inappropriate for use during system setup and EQ.
A-weighting would be inappropriate for use before an RTA used as a spectral-balance judgement tool at concert levels.
How's that?
Again, you're confusing audibility and perceived loudness with other reasons for measuring sound. Recall that phons are based on perceived loudness. A-weighting is an effort produce a single-number representation of sound that roughly corresponds to human perception in that area. C-weighting for higher (100?). Again, this is human perception.
No, I'm not confusing anything, I do understand the difference between audibility, perceived loudness and measurement for safety. We've sort of been talking around the issue, and I think we actually both do understand and are in agreement on much of this.
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The OSHA/NIOSH/every-other-organization-concerned-with-hearing-conservation measurements that started this conversation are not concerned with human perception of a sound, but with its ability to cause damage to hair cells. This is independent of and only somewhat related to human perception. It is a physical phenomenon, not psycho-acoustical. It just so happens that A-weighting also works pretty well for predicting damage to our hearing. It's a different application for the concept, apart from perception. Whether or not the C-weighting scheme works better for perception at higher levels is irrelevant.
There are a handful of papers showing that A-weighting isn't ideal for hearing conservation, including the one you linked to, and I am certainly in the camp that says reducing noise exposure to a single number gives an incomplete picture. But there are also multiple handfuls of papers showing that A-weighting works reasonably well as a predictor for hearing loss, as long as we choose the correct criterion and exchange rate.
Agreed with all.
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The reason you "MUST" use A-weighting to measure levels that individuals in your venue are exposed to is the vast majority of literature and understanding in hearing conservation is based on A-weighted, broadband levels. For better or for worse. It is what we have, even if it's not ideal.
It's not possible to reject the use of A-weighting for this task because it leaves you with no point of reference. You can't just decide to use C-weighting or Z-weighting in place of A, because you can never compare measurements from different weighting schemes. If your criteria are based in dBA, you must measure dBA or your measurements are meaningless.
I believe I've already said pretty much that in another post. We use it because its the standard, right or wrong, its the standard.
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What does using C-weighting tell you about the sound you're measuring? It gives you a better understanding of the perceived loudness of the program material, sure, but what do you do with that information? Serious question.
No, not so much perceived loudness as SPL. It may in some sense be better than the A curve at 100dB SPL, but still not quite right.
So, perhaps we might agree on these:
A Weighting was designed for low (speech level and below) noise measurements, based on old equal loudness curves that have since been updated.
A-weighting is the standard for measurement of high level noise exposure related to safety issues and hearing damage.
A-weighting may not be appropriate for use when perceived loudness above 40 phons is required, but again, is a standard and used all the time. So it must also be used that way.
A-weighting would be inappropriate for use during system setup and EQ.
A-weighting would be inappropriate for use before an RTA used as a spectral-balance judgement tool at concert levels.
How's that?