Learn audio online with Audio Masterclass - AudioMasterclass.com Some of my most popular
videos are about sine waves. So here's a video about sine waves. I'm going to play you some
some sine waves all the way from 20 Hz up to 20 kHz. The question is, can you hear them all?
I'm guessing that you couldn't hear them all. So why is? Firstly, let's listen to some low
frequencies. It depends on what speakers you're using but I'm guessing you started to hear
something around 50 to 60 Hz. The reason you didn't hear anything at frequencies lower
than that is because your speakers can't reproduce those frequencies. If you're listening on
laptop speakers maybe you didn't hear anything at all. But if you're listening on studio-quality
headphones perhaps you heard everything. Lucky you! But what about the high frequencies?
Well that depends how old you are. High frequency perception decreases with age. When you're
really young like ten or under, you can probably hear all of the frequencies all the way up
to 20 kHz. And maybe you could hear even higher than that. But we normally think of 20 kHz
as the limit of the audio band. As you get into your teens and twenties, your high frequency
perception gets worse. Maybe only up to 15 kHz or so. Reach the age of 40 and perhaps
you can only hear up to 12 kHz. By the time you're 60 or so, your upper limit could be
somewhere around 10 kHz. So let's listen to those high frequencies again and you can compare
what you hear with your age. So if you can't hear all those frequencies, don't worry - it's
normal. And if you want reassurance, perhaps you can consider consulting an audiologist.
So let's listen to all of those frequencies again. I'm David Mellor, Course Director of
Audio Masterclass. Thank you for listening.