I’m a 17 year old girl and I could hear up to 20kHz. I admit that I don’t always take the best care of my ears. I go to dances, rock concerts and raves, and I listen to my iPod too loudly.
I’m surprised I could still hear the 20kHz. My friends tell me I talk loudly, and I’ve often come home from concerts unable to hear. Bad, I know. My dad, who was a rocker back in his day, suffers from tinnitus, and warns me about the dangers of loud music. One night, I went to a dance, and the DJ had the volume level up way too high. I thought nothing of it when I got home and couldn’t hear, since that happens to me all the time. Then, I woke up in the middle of the night, and my ears were literally SCREAMING at me.
In the morning, everything sounded muffled, as if I was underwater. I couldn’t remember ever having those effects lasting into the next day, and I was terrified I had lost my hearing forever. After about 2 days (thank goodness) I was finally able to hear again. However, now, I take my dad’s advice seriously I didn’t believe him until I had that experience. Not being able to hear is scary, especially for someone like me. I’m a DJ, and I work with music production and live sound all the time, so I need my ears to be fully functional. It’s not like one night out will ruin your ears forever like I said, I can still hear the 20kHz, but I know I won’t be able to forever if I don’t take care of my hearing.
On another note, I have to say I agree with Dave A and Storyville. These test tones would be better represented in WAV files than MP3s. MP3 audio files are compressed to about 1/10th the size of WAV files. (Don’t believe me? Go to your iTunes, select a song in WAV format, and convert it to MP3. Then compare the two file sizes. The WAV file should be about 10x larger so, for example, if the WAV is 30 MB, the converted MP3 will be closer to 3 MB.) Because these files are so much smaller, the sound quality has been diminished. MP3s can’t produce sounds above 20kHz. Why would they need to? The normal human hearing range is from 20Hz to 20,000Hz (Source: my AP physics class.)
If you are hearing above 20,000Hz, what you are probably hearing is the lower harmonics created by the ultrasonic tones. Dave A’s graphic is an excellent visualization of this. Yes, when I cranked my headphones up, I could hear the 22kHz tone, but interestingly enough, it sounded lower to me than the 20kHz. This is because I was hearing the subharmonics combined with random noise from my computer, not the actual tone itself.
Regardless, it really doesn’t matter if you can’t hear those super high tones! If you are a human, chances are you can’t. My advice to you is to take good care of your ears. Turn down the iPod a little, and don’t spend the entire night right in front of the speakers.
Go ahead, take the free online hearing test to see if you still have good hearing.