Jack's Place: Grounding & Gigging
Handy hints for quiet moments
Ah, grounding - everyone’s favorite. For the record, the following is informational only, designed as a warning to prevent dangerous or illegal behavior. Always do exactly what the electricians tell you. That is our story and we are sticking to it.
The following bits of wisdom are from Fred Ampel, who consults these days but has done a show or two over the years. We were having a little noise problem at a venue once. The split was mechanical. Mechanical means essentially Y-cords, passive means transformers, and active means differential amps (electronic, OK?) or something like that.
To further complicate things we were doing a video shoot. We fought to keep guest splitters out of the hall, due to considerations of space, time, and who gets head split. When you get head (first) split, your stuff is quieter and less susceptible to pops from idiots randomly hitting phantom power buttons (in the mobile), or from electrical grief between the truck Power Distro (PD) the room PD, etc.
Unfortunately, there were special protective transformers on the venue side of the split that covered the recording guys, but screwed the live show with 3dB to 5dB losses and some yucky sounding phase shift 160-ish or so (Marty Sargent was the champ at slipping these into the non-recording feeds).
Now some smart ass is going to write me that there is no head split with a mechanical split, which is technically correct, because everything being fed equally from the same spot. Still, by using our splitter, we prevented things from coming in where we didn’t get head split.
WHERE DID THAT COME FROM?
The point is we were getting too much noise with our little unprotected splitter, so I called up my consigliere, Mr. Ampel, and asked for a fix. He tells me to ground the snake. Then take a male XLR, and solder a long copper wire to it. Plug the XLR into an open channel on your stage box, and strap the bare end of the wire to a real ground. Presto - things get a lot quieter.
If you use heavier wire (8awg solid copper is ideal), it works better. If you have a stake driven into the ground (earth - the dirt) 3-5ft(1-3m). This strategy always works better than believing the electrician’s lie that he gave you a real (ha-ha) ground. And yeah remember, cold water pipe is never necessarily a real ground. If the wire is thermite, or fusion wire welded to the stake, it works better.
September/October2001 Live Sound International