Ground Loop Fix: GenFen TV Wireless RF
We recently held SynAudCon seminars in Singapore, Bangkok, and Shenzhen (China). I brought along my usual case of audio gear, and each venue provided a house AV system. The evolution of the PC – in my case, a MacBook running Win7 under Boot Camp – has pushed me into using HDMI for my video output. The up side is the small connector and cabling size, which is nice for travel, along with being able to carry my own ultra portable HDMI switcher. The down side is that mixing consumer and pro interfaces can result in grounding issues.
My usual process is to setup my tabletop of gear, and then make the final connections to the house AV system. In all three venues, these final connections produced a significant hum and buzz through the house PA. In each case, disconnecting the HDMI video feed killed the hum. We went through the usual litany of “remedies” to get through the events, changing some things that shouldn’t matter in a fully pro audio system until it worked. Remember, HDMI is a consumer format and sticking into a sound system can produce grounding issues. This was a self-inflicted wound, and the price paid for the benefits of HDMI.
The ultimate fix? Another upside of HDMI is the availability of small, low-cost, RF links. The wireless HDMI link that I use in my domestic system would have solved the problem in each venue. It will now live in my travel case as a must-have for presentations on-the-road. pb