An anechoic chamber is a large perfectly insulated room. No sound enters or escapes it's grasp. I've experienced the complete an utter lack of sound produced. It's disturbing and beyond quiet. Your ears tell you something is wrong the second you enter. Eventually you hear body noises you never thought existed. The blood flowing in your veins is audible. Your heart creates a trembling bass, a pattern for your thoughts. It's a place your mind can never be silenced. The tiniest thoughts can be heard.