Ok so I think I might be somewhat deaf ...well not really . I can hear the 10 hz as a noise the 20 hz as oscillation ,right up to 10,000 hz and at 11,000 I'm deaf Ha !.....very interesting thanks Gary.
Listening to the tones through inexpensive earphones, my high frequency limit is somewhere between 12 kHz and 13 kHz...and then I can't hear anything above that! I'm not sure about the frequency response specs of my headphones so I'll try my hi-fi headphones later.
Thank you greatly for posting these files - I downloaded them for future use. Since several increasing frequencies in steps appear in each file (vice a separate file for each frequency), comparison testing is easier to perform. When I have some time, I'd like to run the files through variations of the LM386/LM380 based small amplifiers and look at distortion levels vs. frequency (and vs. power output) on my oscilloscope. Some variations sound better than others and I don't know if it is because of my hearing or the component values that were used.
Running the 4 separate .wav files into a LM386 based amp yielded some interesting results (to me, at least). The 386s are noisier than I thought, i.e, faint background hiss becomes more noticeable on my scope as the frequency and amplitude are varied. Incidentally, the 9 second tone length is about right to get a good visual of the sine before it automatically steps up in frequency. With the single mp3 file, an assessment of an audio hardware's ability to reproduce the audible spectrum can be made in one shot!
Very nifty files for testing/comparing audio circuits (not just our ears!) - many thanks again for sharing them as it must have taken a significant bit of time to make them.