Sound is a vibration of air.
Examples) Security buzzer, fire-alarm device and alarm clock etc.
Air pressure is called Sound Pressure when a sound is propagated through the air.
The number of times of the dilatational wave of air per a second is frequency.
The SPL indicates the sound volume. The unit is decibel (dB). The higher the SPL, the louder the sound.
Minimal loudness of sound perceived by human is defined as 0dB (20µPa).
Sound pressure that Murata’s sound component produces is approximately 70 to 90dB （measured in 10cm distance). The SPL is about 20 dB for a whisper, about 60 dB for a normal conversation and about 100 dB under the tracks of a train.
The more distant the receiver is from sound source, the lower sound gets. “Specification of Sound Pressure Level”: The necessary information are the distance from the sound source and how loud the sound should be there.
In general, man’s audible frequency range is about 20 Hz to 20 kHz. Especially, the frequency range of 2 kHz to 4 kHz is the most audible. For this reason, the most of piezoelectric sound components are used in this frequency range.
Buzzer is a component producing sound of alarm and electronic sound.
Examples) Security buzzer, fire-alarm device and alarm clock etc.
Buzzer plays an important part as a man-machine interface. The buzzers which apply piezoelectric ceramics are “Piezoelectric Buzzers”. We generally call “buzzer”, however, a formal name is “piezoelectric sound component”.
A speaker is a device that converts electrical signals into air vibrations—in other words, it generates sound.
Buzzers and speakers are the same in that they both generate sound. However, they have the following differences.