Temperature/humidity. The same challenges are thrown our way with temperature swings. Tuning a system in Denver in the middle of the summer is quite an experience. During the day it can climb to 90-plus degrees with little or no humidity and by show time it can drop down to the 50s while the humidity can climb a lot. All of this alters the performance and frequency response of the system and will even affect the arrival times of various zones of PA at FOH and in the seating areas.
Once again, the trick is preparation. I like to have shortcuts set up to get to the system processor quickly so I can move the delay time up or down on the subwoofers by a couple of milliseconds. The delay time I settled on at noon (90 degrees and 15 percent humidity) can slide quite a bit at show time, so shifting the time a couple milliseconds up (have a listen), and then a couple milliseconds down (have another listen) can help tighten up the low end.
Also, I’ve often noticed a large increase in upper bass and low-mid in the system as the temperature drops and the humidity rises. When the band starts the first song at twilight, the PA can often sound “tubby” and even “droney” compared to sound check time, so I prepare by having a fairly wide (one octave plus) EQ filter standing by around 200 Hz. It can be parked at 0 dB of boost/cut but having it ready to duck down 3 to 6 dB can bring immediate results.
This effect can be doubly emphasized if the subs are stacked on the ground and there are a lot of concert attendees between them and the FOH position. All those water bags (humans) between the two locations can create some pretty crazy low frequency anomalies that aren’t always pleasant. Be prepared to turn the subs down a dB or two to minimize the madness.
The same can be said for the highs. I usually have a high shelf in the main system EQ set up and standing by in the “on deck circle.” I may set the shelf frequency as low as 3.15 kHz with a gentle upward slope that I can quickly grab and add or subtract from the main left and right if the conditions have changed significantly. It’s like having an output knob for all the highs in the mains like we used in the old days of crossovers!
Rain with wind. Many outdoor concert venues have some form of roof structure above the FOH position to keep the sun from cooking the gear throughout the day, and even plastic walls that can roll down if the rain starts coming in sideways during a storm. This is very helpful for keeping the expensive gear dry but doesn’t always make it easy to maintain our audio reference.
I recall mixing a show a couple years ago where a beautiful night quickly turned rainy and nasty. The plastic walls of the FOH tent were installed on the sides – and front! – making it very hard to hear the PA. I quickly reached into the first aid kit and grabbed the nearfield monitors (which I never leave home without these days – thanks Kristy Jo!), inserted a quick delay time on the solo bus feeding them, and was able to add some clarity to what I was hearing in the plastic bubble.
Another emergency situation that can send the entire team into panic mode is a pop-up rain shower when FOH is not covered with a roof or said roof has been rolled back because we all saw twinkling stars 10 minutes ago. Keeping the gear dry can be solved with a large sheet of plastic, a knife and some quick action.
But how do you mix with plastic covering the console (and you)? I once cut a hole in the plastic just large enough to stick my head (and ears) through and continued mixing the show, looking very fashionable in my audio raincoat. It really can be a lifesaver and get you through a few minutes of unexpected rain.
Let’s all rejoice – summer is here! Pack the raincoat and sun hat, some bandages, sunscreen and bug spray, but don’t forget to check that the FOH first aid kit is all stocked and ready as well. That beautiful, pristine sound check that happened several hours ago can become a distant memory when the elements take over, so be prepared to give your system a little CPR or a defibrillator if necessary. Being prepared to be an audio paramedic can bring a wounded system back to life.
Go here to read more articles by Jim Yakabuski.