Monday, May 14, 2012

Impedance Matching

There's a lot of mumbo jumbo going around in our industry. There are little tricks that people developed to deal with peculiarities of certain pieces of gear and then those tricks kept being used as the gear evolved. Take for example the idea of matching the output impedance of a piece of gear to the input impedance of the next piece of gear down the line. It seems to make sense when you think about wanting to minimize loss in the signal chain. But the thing is, we're not mixing on tube gear anymore (most of us anyway). We're transferring voltage, not power from device to device and solid state ins and outs are set up to transfer voltage with very little loss and very little thought required on the part of the operator. It makes matching the level our only concern and most gear is built with enough control and headroom that it's a simple matter of twisting a knob, not sitting down and doing dB equations.

The article on ProSoundWeb by Dennis Bohn does a great job of explaining this. Even if you don't get all the technical stuff there's a few tidbits in there that are sure to help you out. For example, if you actually set out to build some impedance matching to go between devices, you can accomplish it but when done correctly you actually loose 6 dB because of simple electrical principles!  But don't take my word for it, click the link and check it out. Or bookmark it and get into it when you've got some time and your brain is in good shape.

by Dennis A. Bohn
Originally posted at www.prosoundweb.com

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