hearing tests - where and how?

There is at least one company that makes a CD containing test tones from 20-20,000 hertz their specifications suggest that it is reasonably accurate

AudioCD works well but it does require a very quiet environment in order to get reliable thresholds. Here is a link to my experiences with it.
[url]http://stereophile.com/reference/100digital/[/url]

I visited a high end store some time ago, and although my hearing is perfect acording to a recent test; they demonstrated that I could not hear above 18K. This was done with the use of a frequency generator, a speaker and a decibel meter. All frequencies were generated at a loud level. When they got past 16K, the apparent volume began to rapidly diminish. After they got past 18K, all was silent. Unfortunately that's not the end of the story.
Somehow, I can distinguish in the music between tweeters that go beyond audibility and those that don't. A hearing test does not take "Harmonics" into account.

Very good point, Orpheus. Also, research has proven that the brain can indeed perceive frequencies above those that the ear can hear, which is fascinating. Don't tell that to designers of digital processors, though, the vast majority of whom (at least as of a couple of years ago, anyway) still remove these frequencies as a matter of course, claiming that we don't miss them.

thanks for the responses. Still no success at finding any audiologist in Houston that can do a full-range test. I suspect there may not be any - just not part of their "business model" or the software most of them use now. I've tried the Stereophile test CD test - it wasn't finely calibrated enough to show the midrange flattening I know I have - hoping for something a little more exact. May try one of those cd's intended for hearing tests.