The Numbers Don't Lie.

If you are ever doing a show on a small tropical island, in a tent, in a hotel parking lot, this article may be infinitely helpful to you.  If not, let me share a phrase with you that may be helpful wherever your show is taking place.  It has become a kind of mantra to me, “the numbers don’t lie.”  This short sentence has proven itself true, time and time again, in my live sound experience. I find that you can directly link the quality of audio in your particular room to how you play the numbers.  A speaker in a tent does not adhere to physics any less then a speaker in a ballroom, but it does present it’s own unique set of issues, which I would like to share with you now.

Show Fact List

When: January 23^rd through the 30^th, 2011

Where: Morning Star Resort at Frenchman’s Cove, St. Thomas, US Virgin Islands.

What: Incentive Travel show for Terminix.  Awards show format with entertainment

from Wayne Brady, for the opening segment.

 Gear: 12 Meyer M’elodie Line Array Speaker Cabinets

            6 Meyer UPJ-1P stand mount cabinets

            4 Meyer UMP-1P lip fill cabinets

            4 Apogee AE12 sub woofers

            1 Yamaha LS-9 mixing console

            8 Shure UHF-R wireless microphones (SM58 hand helds, 184 Lav elements,

and Crown 311 mics for Wayne Brady and crew.)

2 MX412 podium mics (again 184 elements)

14 stations of Telex RTS Com

 4 Stations of wireless HME DX200 Com

Thousands of feet of cable to make it all work.

Rigging Chart

The Best Laid Pre-Production Plans…The diagram to the right, is what we were given to figure out room coverage and hang points.  The space was created out of two, heavy-duty, load-bearing tents married together.  The smaller section at the top of the diagram was one of the tents, and was taken up entirely with stage, scenic, video world and screens; meaning I did not need to worry about the house PA covering this area.  So, the question becomes, what is the best way to cover the general seating area? When designing a sound system numbers are good place to start, and here are the numbers I want to know in order to start making effective predictions:

Seating Chart

Room Width: In this case that number was 100’.

Room Depth: 80’

Ceiling Height: Sloped from approx 18’ at the apex to 12’ at on the sides. 

Seating chart: (left) to find out how much of this 80’x100’ area I really need to cover:

Rigging Points: Where are they, and how much weight will they hold???

Most of this info was strait-forward, however, rigging is where things started to get a little squirrelly, and this is where a new number came into play.  If you take a peek at the first diagram (above) again you will see seven horizontal lines, (in the general seating tent) these lines represent the load bearing cross members of the tent. Each one of those cross members can hold a maximum of 1500 lbs in addition to the weight of the tent itself.  You can see that the first cross member was taken by the lighting truss, which was needed to light the stage and set, and which, had I insisted we swap cross members, would have had a lot of trouble shooting light through the 6 M’elodie hang I planned on bringing.  The next logical thought was; “maybe I can hang off of the lighting truss to gain the position in the house I want.”  Let’s consult the numbers:

-M’elodies weigh 62 lbs each.

-Add a 25 lb rigging grid.

-Add motor and cable.

-Equals around 500 lbs per hang, depending on the motor you use.

-Multiply by 2 speaker hang points. 

Not promising…

A quick consult with the lighting department told me they were flying about 1100 lbs of gear, putting the final nail in coffin of that idea.  

Next plan!

The next cross member was 32’ from the down stage edge.  Not optimal, but with nicely sized front fill I was pretty sure I could fill the first 35 to 40 feet with good quality floor supported sound.  As you can see from the seating in diagram 2, they planned on packing this sucker and I was going to need speakers that didn’t take much space.  [Enter the UPJs.]  The plan was to put them on stands 3 per side, just to the outside of the video screens, then use the remaining UPM-1Ps to fill any gaps along the front of the stage.  Was this the best rig for the room?  No.  Was it going to work well? Yes, I was supremely confident it would. 

You may at this moment have the sound of screeching tires in the back of your head, and perhaps your mind is saying, “WAIT!!! Back up!!! Why would you use a PA that you know is not the best one for the job?”  If you are looking for the short answer you can read this and move onto the pre-production section… we were on an island.  If this answer does not quite satiate your curiosity please read on, because it leads to bunch of extra numbers that were not exclusive to just audio. 

I not only had to choose an adequate PA, I also had to choose one that could be out of commission for a while, and I have more M’elodies then any one box in the warehouse.  This is how things transpire when you are going to an island:

-The gear is imputed into the computer.

-It is then pulled and set to the side.  The cases are measured, weighed and tagged.

-This information, plus country of origin (that is where each piece of gear was manufactured) is    

 then used to create a shipping

 manifest.

            -The gear is loaded onto (in this case) 2 shipping containers.

            -Trucked to Miami.

            -Checked out by customs…

            -Loaded onto a ship headed to the Caribbean.

            -The containers go through customs in St. Thomas…

            -And are trucked them from the St. Thomas harbor to the parking lot where

they were waiting for the crew to arrive and load in.

The return trip is the reverse of this procedure, and the whole trip takes the better part of a month including the week of show.  

Pre-production is for making predictions not concrete plans.

We flew into beautiful St. Thomas late afternoon, got checked into the Morning Star Resort, and changed the audio rigging plans, in that order, and almost that quickly.  The seating diagram had been reduced, which in effect, allowed us to ground stack the M’elodies making them the actual main PA instead of a really beefy delay line.  Before we move on, let’s take another quick look at the numbers.  The M’elodies, in their new location were going to be required to deliver clear, even sound across 80’ of tables, chairs and ultimately, people.  The question became, "are they capable of this task even in a ground support situation"?  The short answer is: yes! absolutely, in and of themselves, if you are not in a tent, on a tropical island, they are more then up to the task!  The problem, of course, being that we were in a tent on a tropical island.  You may ask (it would be logical to ask anyway), what was the big deal?  Altitude?  Humidity?  Barometric pressure?  Do people’s bodies become denser when they have been soaking up salt water and sand for a day and a half?  While all of these factors may be true, except perhaps the last item, (maybe we should submit that to Meyer to introduce as a test factor in their anechoic chamber http://www.meyersound.com/products/technology/chamber.htm), the biggest problem can be seen here.  These, as you can see, are very large HVAC units.

HVAC units for tent cooling.

What is shown here are only 3 of the 10 that were actually used constantly to cool the tent. (Did I mention we were on a tropical island?) This created a pretty substantial noise floor problem. Coming to the rescue were the very versatile UPJs, which can be stand mounted or flown.  We opted to go with both methods, spacing 2 about 40 feet apart, on the very center cross member (refer to rigging diagram) and dead hanging them at an angle that gave me nice support for the last 30 feet of seating room (below, on either side of the yellow balloon). 

UPJ Delays

2 More UPJ’s were placed on stands in the same plain as the flown delays, but put on a separate feed for individual EQ, volume, and time alignment control.  

To round out the coverage 3 of the UPMs I brought were used as fill on the lip of the stage (Seen below)

UPMs on the down stage edge

Once time aligned, and a few small EQ curves were implemented, I was able to get a more than workable amount of gain before feedback from both the podium mics and the lavs, despite the high noise floor.    

            

UPM close up

Once again, the numbers worked, or more appropriately, the speakers delivered what the numbers said they would.  If I could give one piece of advice to anyone putting together a PA of any size it would be this:

Scale can deceive your eyes, so don’t just look. (assuming you get the chance) Take measurements and collect the data you need, then, and only then, design your PA for the room. 

(I could not resist adding one more photo below of my ground stacked mains)

M'elodies ground stacked on subs

Happy noise making, folks.

Article by:

Nathan Clark

National Director of Audio

J&S Audio Visual

Show Services 

Originally wanting to get into a recording career, Nathan started working in live sound directly out of high school in order to gain a better understanding of audio.  Employed in the field part time while working on a college degree in economics, live audio quickly became his passion.  Deciding this was the career path he wanted to follow Nathan initially hired on full time with Dallas Stage Right, then in 2004 struck out on his own as a freelancer.  Nathan came on board with J&S Audio Visual as the director of the audio department in 2007, and is excited about new technologies on the horizon, and looking forward to tackling the opportunities they present with the rest of the audio team.