Yeah, last time I gave myself a self-test, I think I could only hear between 30Hz-16kHz. And that's probably stretching it a little bit. Probably more like 32Hz-15kHz.
I've done some testing with folks before, including myself. It's really important that you are absolutely certain that your reference source is adequate. I was using headphones in the first round from Sennheiser (HD600's) assuming these highly regarded headphones had a good response from below 20hz to above 20khz and that this would be fine. Turns out that was incorrect and they had both a lack of deep bass and rolled off highs.
Since then I've obtained headphone measurement gear that is at least good enough to assess as reference the speakers and headphones. I've also taken to using accepted standards of testing headphones like the Etymotics (and there is not a special DSP curve that has been validated to flatten out their response for audiology testing).
All to say that, when I retested myself, the results were dramatically different depending on which headphones I used. I've not had a chance to test anyone else since getting all of this. I might have James come over at some point to see what happens.
All of my measurements for headphones and speakers have largely shown that, in a room (for subs) and on my measurement rig for headphones, most are producing harmonics about as loud or louder than the fundamental. I have two subwoofers in my posession for which that is not true and one headphone set. The Headphone isn't able to reach sufficiently loud however for proper testing.
Since I own a lot of decent gear, I have to surmise from this that many peoples speakers and headphones probably aren't adequate to reliably test 20hz and below accurately. Only my 18" ported sub could do 16hz with sufficiently low distortion at reasonable outputs and frankly there is an audible chuff you can hear that I think would clue someone into thinking they are hearing it when they aren't.
Just because a system measures flat to 10hz doesn't mean its producing sufficiently noise free sound at 10hz to do auditory testing of such frequencies. I honestly would question anyone who says they know they can hear below 20hz.
For myself, I am not usually able to hear 20hz, but based on threshold testing, I would need to be able to produce probably around 80dB clean at 20hz and an unknown level higher than 80dB at 16hz for it to be barely audible. That turns out to be pretty loud for a lot of subs, even in room, I believe I have 3 that meet the criteria and only one, the 18, that I think would actually be clean enough for a reference source. Among my headphones, I have only 1 pair that is sufficiently clean at that threshold at 20hz. Nothing that is producing much output below 20hz with low enough distortion. I think part of the problem might be that most subs have a 3rd harmonic that dominates at those frequencies, that is 60hz, and the threshold of audibility is about 20+ dB's lower at 60hz than at 20hz. So the distortion needs to be more than 20dB down from the fundamental in the 3rd harmonic. Giving some buffer, that means less than 5% 3rd harmonic at 20hz at 80dB. Many subs can't do that.
