Wave motion in air with a frequency between 20 and 20,000 Hz that produces a sensation of audibility. The audible spectrum varies slightly from individual to individual. High frequency perception decreases with age of the listener.
"I received the cds today and I can't thank you enough. My Mom just passed away and hearing her voice talking to me when I was a baby was so special. We also are going to be sending you a few homemade records that we've found. I'll let you know when they're in the mail. Thank you again,"