| Popis: |
A bimorph sheet of polyvinylide‐fluoride (PVDF) film was applied to a flat rectangular loudspeaker as a folded zigzag‐tack shape diaphragm whose size is, e.g., 260–144 mm with various depths. These loudspeakers, which we call bimorph tuck loudspeakers, are characterized by their moderate size, wide frequency range, light weight, and lack of magnetic flux radiation. This study examines the electro‐acoustic transducer characteristics of these loudspeakers. Their sensitivity and resonance frequency were measured using a flat‐panel baffle. Their electrical properties and sound field characteristics were also examined. A speaker’s resonance frequency was estimated theoretically as a function of tuck depth. The measured resonance frequencies were, for example, 200, 160, 90, and 60 Hz. These low resonance frequencies are satisfactory for full‐range loudspeaker use. Frequency characteristics of output sound pressure were also measured. They still include some irregularities that are attributable to a local bendin... |
