Examination about Frequency Properties of the Heat Speaker Using the Stirling Cycle (Reduction of the Amplification Factor Associated with the Decrease of Displacer Movement)

Abstract

In the previous report, as a new application of Stirling cycle, it is proposed to apply the Stirling cycle to heat speaker which amplifies sound vibration by means of thermal energy. In present report, the characteristic of this speaker was discussed and applying this theory an experimental device of heat speaker was developed. Using this device, the frequency characteristic of heat speaker was investigated. As a result, the amplification factor by heating decreased with frequency, and at the level of above 85[Hz] the amplification factors were minus value. The result of decreasing amplification factor is likely caused by decreasing of the movement of displacer attached to the voice coil.