AES Section Meeting Reports

Shenandoah University - October 18, 2010

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Mike Sokol's No Shock Zone lecture concentrated on eliminating hums and buzzes in audio systems as well as avoiding electrocution. Mike started by explaining what hums are and how they are caused by ground loop currents between two pieces of gear. Mr. Sokol explained that these ground loops happened because of changes in voltages between two pieces of gear plugged into different wall outlets. Regulation says outlets can vary in two volts from each other. This two volt difference causes current to flow through the XLR cable that is connecting the two pieces of gear causing the annoying hum. From here, Mike explained how to eliminate these ground loops by using isolation transformers or DI boxes.

Mike also explained many of the wrong ways people take care of hums. The main way is lifting the ground from an amp or a mixer, one of the most common ways people are shocked. He explained how dangerous this could be. The best example of how dangerous not properly grounding your gear was when he powered his entire rig with 120 volts of alternating current. The rig looked the exact same and there was no way to tell his rig was electrified and capable of killing someone. Using a Fluke VoltAlert tester, Mike was able to show the rig was electrified and showed how useful and life saving this tool can be.

Mike was open to questions and also had many great personal stories to share with everyone.

After Mike talked, Donald Taylor gave a demonstration on how to help someone who had been electrocuted. Donald explained that the most likely thing to happen would be cardiac arrest and demonstrated compression only CPR, which is a much simpler version of CPR.

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AES - Audio Engineering Society