By properly matching the input and output impedances we achieve a much wider bandwidth than the original tin can mic, and also the circuit can drive the signal along a very long run of mic cable. Further, this circuit provides a high input impedance to the piezo disc, and also a low output impedance to match a mixing console input. A balanced signal is extremely quiet, providing high signal-to-noise ratio. The heart of the mic is a tiny phantom-powered circuit (originally designed by Alex Rice) which creates a balanced output signal from the piezo disc. Following are some comments on each of these features with suggestions for variations and custom mods. They include the Resonator (A), the Shielding Container (B), the Balancing Circuit (E) and its Grounding Wire (F), and the Resonator Suspension system (I).

These are the parts that we think are key to the performance of the microphone. You should be able to adapt and apply these principles to your own unique project.įigure 2 illustrates the essential components of our Tin Can Mic. This article will explain the essential design considerations we put into our Tin Can Mic. Using common household items along with a simple circuit, this mic has a tonality similar to the classic tin can mic (for all you Tom Waits fans), but improves upon nearly every other feature. To overcome these limitations, we at Zeppelin Design Labs developed the “New and Improved Tin Can Microphone” (Figure 1), which is described in detail in this Instructable. These issues usually result in a very noisy and brittle sounding microphone. These types of microphones are nice because they are so easy to make, but they are quite limited in most other areas, including bandwidth, microphonics, signal-to-noise ratio, impedance matching, and cable driving. Most DIY audio enthusiasts are familiar with the standard “tin can mic” (or variations thereof), in which a piezo disc is taped onto the bottom of a tin can and then plugged into a high impedance voltage amplifier, like a guitar amp. Today's blog post is written by Glen van Alkemade of Zeppelin Design Labs.

Small piezo disc