Sound consists of waves and when the sound hit a hard surface it continues to reflect back into the room, which creates reverberation. However, the acoustical panels breaks and absorbs the sound waves when it hits the felt and the slats. Hereby it prevent the sound from reflecting back into the room,which ultimately eliminates reverberation.Apparently on graphics, the panel are most effective at frequencies from 300 Hz to 2000 Hz that covers a big range. Actually it means that panels will extinguish both high notes, and a deep sound. The loud speech and usual noise in the house will be in the range from 500 to 2000 Hz, and, apparently on graphics, exactly here the acoustic panel is the most effective.
link:https://www.lvildiy.com/acoustic-panel/acoustic-wall-panel/Soundproofing-Wooden-Grooved-Hotel-Cinema-Acoustic-Wall-Pane.html