The closest I think I've come to anything like this is a "soundproof" booth used for hearing tests. I remember that being eerily quiet (to listen for very quie

The closest I think I've come to anything like this is a "soundproof" booth used for hearing tests. I remember that being eerily quiet (to listen for very quiet tones in headphones). Anyone know how this chamber compares to a hearing test booth? Sounds like it's probably quite a bit quieter...