Grooved panel is made up of a series of stats on ... and the other side is a series of round holes. Grooved panel is made up of a series of stats on ... 15MM, other size: 12MM, 18MM.Generally, grooved panel absorbs for middle and low frequency.If grooved acoustic panel sticked on by the ... space with the wall, all noise frequency can be absorbed.Grooved panel can be used in meeting rooms, offices, halls, ...