If the sound-absorbing cotton is filled in the wall, it will have no effect on the music effect. The more sound-absorbing cotton, the better the sound insulation effect. However, if the sound-absorbing cotton is used for sound-absorbing treatment on the surface, it cannot be used too much, which will seriously affect the music effect. KTV private rooms require a certain amount of reverberation. Too much sound-absorbing cotton and no reverberation will make the sound quality dry. For KTV private rooms, keep indoor reverberation. It takes about 2s.