ACOUSTIC DEVICE FOR WARNING SOUND AND ACOUSTIC SYSTEM

摘要

An acoustic device for warning sound and an acoustic system are provided which are configured to increase, also when a warning sound at a relatively low frequency is output, a sound pressure level of the warning sound. An acoustic device for warning sound includes a switching circuit and a resonance circuit. A relationship among a frequency fn of an Nth harmonic, a fundamental frequency f0 of a drive voltage V2, and an oscillation frequency f1 is fn-1/2f0 ≤ f1 ≤ fn+1/2f0, where the Nth harmonic is one harmonic of a plurality of harmonics of the drive voltage V2, a sound pressure level of an output sound from the piezoelectric buzzer at the Nth harmonic being higher than a sound pressure level of the output sound from the piezoelectric buzzer at the fundamental frequency f0.