Music studios use “soundproof” recording rooms. The walls of these rooms are designed in such a way that the only sounds that reach the microphones inside the room are sounds from inside the room. The most important characteristic in designing the soundproof room is to create walls that–

- don't echo sound and don't create a reverb

also, these walls are designed to maintain a uniform pitch and amplitude in every corner of room

are you referring to matrix mathematics!

because the two particles have an equal charge, the charges will cancel out and give the atom an overall charge of 0. so, if at atom has 35 protons in the nucleus, we could expect it to have 35 electrons orbiting that nucleus.