Abstract: In recent years micro-perforated panels are widely used as fiber-free acoustical material in the form of wall or ceiling covering with some air space behind. This paper describes the acoustical characteristics of two different types of functional absorbers, flat panel type and cylinder type, constructed with micro-perforated metal or urethane plastic sheets. Acoustical measurements of such functional absorbers in reverberation chamber demonstrate the merit of good absorption as expected. They are also effective cost wise in construction and installation, and esthetically for initiating innovative architectural interior design. The theoretical analysis of the flat panel type functional absorbers will be discussed in a separate paper.