Deep Contact

Air microphones are not the only way to amplify real world sounds. In DIY Audio, we also made contact microphones. Contact microphones are placed in direct contact with an object then amplify the vibrations of that object. We made our contact microphones by opening a piezo buzzer and removing the copper and quartz plate inside. We then soldered the two wires coming from the copper plate to an 1/8th inch male connector. The copper plate is glued to a very thin piece of quartz. When quartz is compressed, it creates a very small electronic signal. When the copper plate is pressed against a surface, vibrations from that surface compress the quartz and create a signal representative of the surface vibrations. This signal can then be amplified. When we plugged the copper/quartz plate (contact mic) into our mini amplifiers we were able to create all kinds of interesting sounds. Contact mics can be used to amplify heart beats. They can also be used to turn ordinary objects into musical instruments. Contact mics are best used for percussive sounds. These microphones can also be used underwater which is one of their biggest advantages over air microphones.