2008年6月1日 星期日

Buzzer and Speaker 蜂鳴器與喇叭的比較

喇叭與蜂鳴器都是發出聲響的零件,若只是想發出一些警告音,提醒音,這二者其實都是可以使用的:Buzzer and speaker are the acoustic components that can generate sound, if you just need sound to warn or remind, both of them are fine.

蜂鳴器分為電磁式及壓電式二大類,在耗電流,尺寸,頻率,驅動方式上有些不同,但基本上都是將某一個頻點的音壓拉到最高,以期用最小的尺寸,就可以發出很高的音壓,若不在諧振點的音壓就會很小,甚至會相差20dB以上,且蜂鳴器的聲音,由於是用方波發出來的,人耳聽起來就比較刺耳一些,We divide buzzer into piezo and magnetic buzzer. There are some differences in power consumption, dimension, frequency and drive method between piezo and magnetic buzzer, however, both of them basically pull the SPL to the highest at a certain frequent point in order to generate as high SPL as possible in the small size. The SPL will be very low if it is not at the resonance point, even 20dB difference. By the way, the sound of buzzer is drove by square waves; therefore it is harsh to the human ears.

小喇叭是以弦波推動,相較於蜂鳴器人耳聽起來會舒服許多,但因為頻寬較寬,可用的頻率也較低,故在同尺寸時,音壓一定會小於蜂鳴器,且需要音箱的輔助來增進低頻的響應,不然整體的聲音會很小.Micro speaker is drove by the sine waves, to compare with buzzer, the sound is much more comfortable for us. However, the bandwidth is wider, and the frequency is lower, therefore, the micro speaker’s SPL must be lower than the buzzer with the same size, and also need enclosure to help the low frequency, otherwise the sound will be very small.