For the following demonstrations, you will need to use headphones and make sure you wear the headpones correctly (i.e. left headphone worn on left ear).
Locate Each Sound
You will hear someone count from 1 to 9, but each number will be said at a different location. Can you locate each sound? You will hear what this sounds like for people who can hear with their two ears as well as for people who are deaf in one ear. Can you hear any difference?
Listen to One Person
You will hear two people talking, and each person will say a sequence of numbers. Try listening to one person and ignore the other person. As before, you will hear what this sounds like for people who can hear with their two ears as well as for people who are deaf in one ear. Can you hear any difference? Try listening to the person on the left. What numbers are they saying (try a few times if needed and check your answer below)?
Person on the left is saying: 6189 777 462
This illusion contains a sound that always appears to increase in pitch, no matter how long you listen to it (known as the Shepard-Risset glissando). The sound repeats itself every 15 seconds (i.e. the first 15 seconds are identical to the second 15 seconds etc.) but you can right-click on the video and click on ‘loop’ if you want to listen for longer than 2 minutes.
The sound consists of multiple tones playing together at the same time, and each of these tones is rising in frequency. In the video, each tone is represented by a horizontal line (darker/bluer colours represent tones that are louder). You will see that each tone (i.e. horizontal line) gradually disappears when it gets to a very high frequency. At the same time, a new tone appears at a very low frequency. Because there are lots of tones playing at the same time, it is very difficult to hear a single tone appearing or disappearing. It therefore sounds as if all the tones are continually increasing in frequency (which is heard as a continual increase in pitch).