1] Reverberation – The time it takes the sound to die after the sound source has stopped. “A dry room” has a short reverberation time and “a wet room” has a long reverberation time.
2] Absorption – In acoustics a property of a material. Absorbing material converts sound energy. The absorption of a given material varies with frequency.
3] Reflections – Hard and thus not absorbing, surfaces reflect sound. Reflections are the reason for reverberation.
4]. Standing waves – Waves that fit into the room dimensions can affect the distribution of the sound. All rooms have standing waves.
5] Room size – The room size influences the sound of your recording. Larger rooms also have higher reverberation time. Too small rooms like speak-boxes may sound too boxy.
6] Background noise – The unwanted noise from installations, outdoor traffic, etc. In good rooms for audio, this noise should be kept as low as possible.
7]Mechanical vibrations – Mechanical vibrations may eventually end up as sound in the microphone. This is why it is recommended to apply mechanical damping of microphones.