In an anechoic chamber, there are very few echoes. The surfaces of the room are designed to stop reflections of vibrations, making it astoundingly quiet in the room. When you're in the anechoic chamber, you can hear direct noises but no reflected sound. This means that if you yelled "Hooray," you'd hear yourself yell it, but there would be no echo. (© Daniel Wong-McSweeney / CC BY-SA 4.0) In order to understand what an anechoic chamber is, you need to understand how sound works.