Like ultrasonic applications, piezoelectric crystals are now widely used for smaller sized sound production. This is due to the underlying mechanisms of piezoelectricity, which are simplicity and efficiency. Higher-end sound producing systems still utilize more powerful electromagnetic speaker technology.
Piezoelectric speakers utilize a disk actuator attached to a resonator or diaphragm. These speakers must use an alternating current to create the vibrations. The resonator or diaphragm serves to amplify these vibrations so they are audible.
Buzzers and Beeps
One of the most common uses for piezoelectric speakers is to create simple sounds including beeps and buzzers. For example, digital watches often use small piezoelectric speakers to create various sounds based on piezoelectric sound production. Most other types of speakers are too large, while piezoelectric speakers can be as small as one millimeter in width.
Other Speaker Systems
Piezoelectric speakers have been used in a wide range of low-cost applications including computer speakers and ear buds. A big advantage of piezoelectric sound production is that products using this technology are not normally damaged from overloads. While most speakers would be destroyed under extreme conditions, piezoelectric speakers are resistant to many kinds of abuse or damage.
Piezoelectric speaker designs can cause damage to amplifiers. Piezoelectric loads can cause amplifiers to vibrate, which can deform them and greatly affect sound quality. Designs, as with all speakers, must be carefully created to resist these problems. The pitch range of piezoelectric speakers is not as robust as other speaker-based systems. Therefore, they are commonly used in more simplistic, single-pitch or reduced-pitch applications.
It is worth noting that the pitch range is not a huge issue. By designing multiple piezoelectric actuators of different operational ranges to work together, problem can be simply solved and more complex sounds can be created. Technology advances has enabled the clarity of piezoelectric speakers to rival that of many other sound system technologies, even surpassing older television speaker performance.