Introduced in 1968, Controlled Sound heads are single ply ambassador-weight heads with a 5 mil thick black or clear dot in the center of the head. This combination offers a controlled, centered sound without undesirable "overtones." These dual-zone heads have a combination of medium and heavy-duty drumhead characteristics. The outer area of the head's playing surface offers a mid-range tone and sensitivity while the laminated center "dot" eliminates high frequency overtones and adds durability and tonal focus to meet the demands of heavier hitters.