Introduced in 1968 Controlled Sound heads are single-ply Ambassador-weight heads with a 5-mil thick black 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 drum head characteristics. The outer area of the head s playing surface offers a midrange 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.