Bing Carbon Microphone

TapeOp Issue #66/July, 2008 | by

Check out these little lo-fi gems. The Bing Carbon Mic is made from retired telephones, but [is] transformer coupled to provide a balanced XLR connection for studio use. It comes in a compact housing complete with built-in mic stand adapter. Depending on inventory, you can sometimes specify the decade your carbon element was manufactured.

Now, for the PBS section: Carbon elements have a limited frequency response (hence, the term ‘telephone sounding’) but they are very durable, and can be used in a variety of effect situations.

The mic element is constructed by sandwiching carbon granules between two metal plates. A voltage is applied across the plates, which sends a current through the carbon molecules. Sound striking the diaphragm causes it to vibrate, which, in turn, changes the pressure on the carbon. The pressure fluctuations change the contact area among carbon granules, which changes their electrical resistance. This causes a change in the voltage across the metal plates, and down the line: the electrical output from the mic.

From vocals to guitar solos, we had a lot of fun with the Bing (using it as an effect mic). In more traditional applications, it did a cool job as a room mic, on the snare batter head for brush work, and with harmonica. It even sounded neat on some acoustic and nylon guitar tracks. I will warn it is easy to overload the element, especially with loud sources. So try to start further away than you would with a large-diaphragm condenser.

Read more about the Bing Carbon Microphone.

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