Review of Anechoic Chamber

Anechoic room was dead silence. I really can't get used to a place got -2db, as I hear lots of loud music. My ears seems to produce some noise, just like when I went to gigs, the ringing high frequency noise. The room is decorated by spiky sponge, even the ceiling and floor. As what professor of AU test in front of us, which put a speaker inside a box and put different material on top of it, include sponge, glass and wood. Sponge was typically being thought the one will absorb the sound, but the sound still came out after he put on. When the wood was put on, the sound was extremely reduced. I was thinking is that means the sound can go through the sponge, but the volume inside the box was decreased. On the other hand, the wood reflects the sound back, is it increased the volume inside as we couldn't hear from outside. For instance, if we are in a sponge room, could people from outside hear the noise we make inside, or if we are in a echo room, the noise is reflected back in, the volume is relative reduced to outside. Thus if we play constant volume of sound, which one actually got better noise isolation, for inside or outside?