Craig
I was talking to my brother about your upcoming speaker comparison, and being an Audiologist (tests and treats peoples hearing) he thought it would be interesting to test all the participants hearing before the test to see how that coresponds to the end results.
According to him, if he were to test 100 random people, at least 90 of them would have some kind of hearing loss in the 1000-8000 khz range.
If you are interested (may be a bit much) he said he could probably find an audiologist in your area that would be interested in participating in your test.

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