9. What to beware when inputting audio signal?
It’s advisable to input square signals into buzzers, for sine signals would impede their output SPL and vibration. Furthermore, pure sine signals are harder to generate, as a distorted sine signal will produce noise as well. Clients can control its SPL by tuning the duty cycle of square waves: 50% duty cycle yields maximum SPL, while 1% duty cycle yields minimum SPL. The above directions apply when buzzers operate at their rated frequency.
It’s advisable to input sine signals into micro-speakers. While buzzers are able to endure square signals thanks to their vibration mechanism, micro-speakers may suffer from burnt coils when inputted by square signals for a long time. So clients are advised to apply sine signal to a micro-speaker, to generate beeps more comfortable to human ear.
Technically when it comes to Fourier Transform, sine signals are “pure” signals consisting of only its base frequency. Square signals comprise its base frequency and its odd harmonic frequencies, which add a noise-like element to human ear.
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