These Illusions Fool Almost Everyone

I want you to listen to these two sounds and decide which is higher so this is Sound a and this is sound B okay so to me sound a is clearly higher but that's strange because sound a was just a 100 HZ sine wave sound B had that same 100 HZ frequency but also 150 HZ and 200 HZ so we added higher frequencies but the sound was lower how does that work I think there's this idea that what our ears do is simply detect the frequency of vibrations in our environment that are between 20 HZ and 20,000 Herz but there is so much more to hearing than that and in this video we're going to go through a series of audio illusions that illustrate how our sense of hearing actually works most of these effects will work on a phone or laptop speakers but if you have headphones handy well I'd recommend putting them on for The Full Experience [Music] [Laughter] it's like a whole body instrument isn't it absolutely yeah yeah this is the Sydney Town Hall pipe organ when it was built in 1890 it was the largest organ in the world something I didn't realize about organs is that they were meant to sound like many different instruments playing together organs are sort of a onep person [Applause] Orchestra very fluty right yeah you can tell compare that to a trumpet OBO sound so you can hear the all these orchestral sounds on the on the organ we could get inside the instrument too should we go look let's have a look yeah okay for each instrument there are a series of pipes in the organ which play all the different notes for that instrument I mean there are 8,000 pipes in this organ 8,000 8,000 yeah why do you need that many to create all the different sounds of the orchestra what you see on the outside is just a tiny fraction of the organ itself wo look at all these they're all hidden in here they are yeah and some are wooden some are metal some have resonators at the bottom of them uh to create the more Rey sounds the brassy sounds but then these wooden ones are more of the deep fluty sounds as well so this is like what a keyboard it's a keyboard yeah that's right ...