Perfecting Sound in the Wrong Environment

Ideas are magnetic and once a concept takes hold, minds and innovations seem to congregate, refine and push the limits, often to the point of absurdity. Or at least way past the point of diminishing returns. Meanwhile there are seemingly gaping holes between the popular concepts and those in dire need of resolution.

Take a moment and picture the scenario of setting up a table layout for a grand formal dinner with perfectly folded napkins, crystal champagne flutes, fine china and pristine cutlery placement. Confident with the presentation as guests begin to arrive you realize that mysteriously the table, upon which the masterpiece is set, begins to morph into something similar to a slightly undulating water bed. The exquisite meal now sits precariously balanced upon a liquid filled membrane as the stream of  guests obliviously lean against and push waves into rolling motion. Glasses toppling,  food sloshing and culinary chaos ensues. With a flurry of panic,  the staff reaches in all directions to regain control, sop up spills and replenish the losses. Just when it seems the entire meal will be hopelessly lost to calamity, the intensity begins to ebb, all that will spill or break, has already The messes become familiar, you’ve the replaced champagne flutes with more stable coffee cups on saucers. All excess frivolity has been carted away. A balance has been reached, tensions relax with a new and different result than the original intent but the wonderful food and smiles ramp up into a meal to remember with a rough start. The following day we begin our task again, we set this table carefully attending to each detail and once again the arriving guests are subjected to a chaotic start to an evening meal mess perched atop a rippling unstable surface. Over and over again each night the mystery repeats with us scrambling to resolve the issues as they arise. Until one day it dawns upon us and we realize the table has always been made of melting ice turning to various levels of slushy water each night sometime between preparation and meal time.

In this equation, we as sound engineers and system techs are the waiters setting the table, the band is the chef in the kitchen and the show audience is the dinner guests. Not unlike the sloshy water table party, we too as sound engineers, face the challenges of a changing and interactive environment. The venues we setup in may well be the same physical dimensions throughout the night but come showtime, the world we mix in often has significantly differing acoustic properties. My questions are: With so much precise analysis and prediction, why do we still enter showtime with so many loose ends unresolved? and Why do we not have an advanced set of tools to solve it?

I find tuning sound systems to be a real world example of what I wrote in the first paragraph regarding people clustering efforts in one direction while turning a blind eye to other critically important issues that dramatically effect the quality of the outcome. For example; it is not uncommon to spend surprising amount of time fine adjusting every single detail of time alignment, phase alignment and loudspeaker positioning resulting with complex EQ curves and extremely precisely calculated alignments. Then, after all of that time and energy spent on tuning, it is naturally tempting to have a  a vested interest in the correctness of those settings and to embrace an “I have this perfectly dialed in, don’t touch anything” mentality.

Meanwhile, many if not most situations wherein a sound system is setup, tested and tuned for sound check we find that the tonal balance and coverage of the sound system has significantly changed by show time. Perhaps we knowingly already made some predictive adjustments, perhaps we kept our settings from the previous night, to fall back on or maybe we just avoid soundcheck tuning altogether and use a previous gig file with some modifications for system configurations changes. Regardless, there is the clear and persistent disconnect between what we measure in an empty room and what we experience at show time.

Why? Why does the status quo of system tuning seem so relentlessly shortsighted? Is it ok to be repeating the same plan over and over again when nearly every time the results are flawed? Is the change in sound just some odd mystery that no one truly understands or is it just so unsolvable that we just ignore it and do a blind approximation after spending hours avoiding approximations?

Ah yes, its been repeated so many times it has actually become humorous. “Yeah yeah, it will sound better once the room is full” mocks the band back at me when I used to offer that as an explanation. Somehow as if we have the sound now and then we will have a different sound later and since we have no way of knowing what the other sound will be except different and most likely better but usually worse at first before we fix it.

Is it possible to bridge the gap? Is it possible to predict and compensate the difference between an empty and full room? Cold and warm room? Sunshine versus nightfall? I realize it may be a complex endeavor to predict the way an audience and environmental factors will alter the sound of a venue, but how complex? More complex that predicting the weather week in advance or designing a digital processor? We know where the people will be. It can not be that complex to calculate the approximate sound absorption of typical clothing and the sonic diffusive nature of a cluster of  human bodies. We know the average skin temperature and it would not be a stretch to calculate a thermal range for the amount of heat generated by dancing versus sitting. In most indoor venues we can have control over the room temperature and for outdoor venues, it is pretty easy to find out approximately what the air temperature will be. Is it truly out of our realm to continue the meticulous system tuning and carry it forward into the probable influences of the known factors?

One common issue I encounter involves flown clusters at outdoor festivals. Here are three scenarios:

  • The coverage area that the predictions software indicates based on the temperature used in the calculations
  • The actual coverage that occurs during the warm day wherein that heat from the ground refracts the sound upward and extends the coverage area, sometime hundreds of feet.
  • The coverage where the ground is colder than the air and shortens the coverage until the audience brings in their warm bodies creating a warm layer and extending the coverage.
As the coverage area is increased or decreased, there are also noticeable tonal changes that occur. The refractive changes caused by temperature are more prominent in high frequencies which means that as the coverage area is reduced, the sound in the coverage area gets brighter.
Ok so out of all of this, here are a few things:
  • The sound of a venue over time is dynamic and constantly changing due to numerous factors, I covered mainly thermal but wind, diffusion and absorption by humans as well as attenuation of frequencies over longer distances due to temperature/humidity.
  • Prediction software will not give you correct results if the real world environment is vastly different than the prediction environment. If the prediction is for 70F and the venue has 85F degree humans packed tight on a 60F degree night, the actual coverage will be way off.
  • It is important to properly tune and align a system, it is also important to be prepared for the inevitable changes that will occur when the people arrive and environment changes. Take note of the changes that occur and build a strategy for dealing with them into your system tuning plan.
Here are a few things that I do:

First of all, knowing that the venue sound is constantly changing I follow a “what EQ’s what” strategy. I use the channel EQ’s to make the mic/instrument combo sound correct.  I use the system processor  to fix any issues with the sound of the loudspeaker system design and array configuration issues. And I use a house EQ as a hands on control to deal with the constantly changing room sound.

For over a decade now I have been carrying an infrared thermometer which I use to measure room temperatures and work with the production manager and venue to try and create a consistent thermal environment.

I started using a Fluke Thermal Imaging Camera so I will be able to take more accurate readings.

I wrote an article called Thermodynamics of a Rock Show for Live Sound Magazine a while back which was nice to see recently re-released.

I posted  youtube video showing how a heatgun can demonstrate the refraction of sound away from the heat.

In the Youtube video I used a highly directional Parametric Speaker by SoundLazer which functioned well for the demonstration but I I felt the demo would be even more credible if I used a conventional sound source. So I did a short instagram video showing the heat from a stove burner altering the sound from a Jambox speaker.

Here is an article called Thermodynamics of a Rock Show for Live Sound Magazine a while back which was nice to see recently re-released.

Here a great article by Dennis A. Bohn from Rane Corporation:

Cool cool, as you can tell I am dwelling further into the heat aspects of sound for awhile.  Hopefully to find some ways to make things a bit more predictable.

Owning a Tesla 4 months 10000 miles 

Edging on 4 months of cruising the new car and since everyone loves to ask – “How do you like the Tesla?” , figured I’d kick out an update.

If you have not already done so, maybe give a read to my last blog post after 10 days of driving the car.

I have been taking notes and it is a long list because of course I over analyze everything, so I will break this up into several posts, so here goes part 1:

1) Since I never put gas in the new car and wake up with a full tank everyday, it is really easy to lose track of how much I drive. Heck, I drive everywhere now, all the time. It not only feels free and environmentally impactlless, it feels like a waste of car not to!

2) I forgot to mention in the last post that the car stereo volume goes to 11, a wonderful ode to Spinaltap. But why stop there? The air conditioning / heater fan speed also goes to 11. These are important details that the designer side of me greatly appeciates. I put hidden connections in nearly all my speaker system designs.

3) Autopilot has different concept of optimum lane position than I do. For me, it swings wide on turns and is equally comfortable next to a car as a semi. Also it is not overly concerned about driving in someone’s blind spot. It has a ways to go before being a hands off nap taking adventure. It is more like having a pall hold the wheel for a bit that will slam on the brakes if you get distracted.

4) Most fast flashy cars are all about “vroom, hey everyone looking at me, I go fast, vroom vroom, hey, me fast look over here!”

The Tesla is more like “Hey, have you heard the new Portugal the Man album? Oh wait a sec, need to say bye bye to a big noisey muscle car, ziiiiing, hello cute little muscle car in the rear view mirror, so yeah their new album awesome

5) It’s a big car! wide and roomy, I went from an Infiniti EX 35 small SUV to a Tesla model S sedan and I have way more room in every direction. Plus, the Ex35 got a pathetic 20 miles to the gallon. I feel years of mileage wasted regret.

6) Tire pressure matters, in fact everything that would matter to you on a self pedal bicycle on a long ride, probably matters to some degree. If you obsess on trying to get maximum miles per charge, speed, how fast you accelerate, tire pressure, anything on the roof, hills, headwinds, they all matter. Thankfully, compared to gas electricity is either free or super cheap and costs around $10 to $12 for 250 to 300 miles.

6) Backing into the garage does not make the house smell like exhaust.

7) Bluetooth transition from car to phone is super awkward. With a normal car, turning off the car mid phone call, auto switch to handset, all good. With Tesla, you don’t really turn off the car, so park, open door, stereo volume drops making person you are talking to inaudible, get out, close door, person gets loud again but is still inside car and can’t hear you. Walk away, lock car and handset starts working. It really messes me up when I am on the phone at work and go get something from the car.

8) I had to drive my 2008 Infiniti and wow, how easily I became unadapted. It was like switching back to a flip phone where texting required me to press each key multiple time to find the right letter. Most odd was the lack of regenerative braking made it feel like it was trying to crash me into things when I let off the accelerator. It just keeps rolling and going and then I have to actually use the brakes! In a Tesla, brakes are only for emergencies and to stop from rolling after you are nearly stopped.

9) With few exceptions, with a Model S, the car you are replacing is slower, noisier, dumber, smaller or all of the above.

10) Gas cars grunt like they are doing heavy lifting when you gas them, an electric car doesn’t complain, it just effortlessly debits your energy reserve

Cool cool,

Dave Rat

New blog adventure 

LAX tarmac headed to Munich and admiring the closed widow shades, relaxed demeanor of the flight staff and am not being treated like a misbehaving school child.

It must be my 12th transatlantic flight this year and I never cease to be annoyed when airlines scold the passengers as if they are idiots for expecting the plane could possibly navigate a takeoff with even one closed window shade. Yes we already know a seat back tilted makes a plane unflyable.

Probably more importantly I am just being sensitive and annoyed at leaving behind my wife and daughters and little four legged pals all gathering for a Halloween party without me.

Fly away to make invisible sounds and immerse in the energy of giant rock shows. Over 25 years of my life spent traveling the world with so many friends I truly love and respect, torn from one world to the next. 

Going to take a shot at ramping back up on some blog posts as I adventure about. Really looking to consolidate the info I post into a single feed rather than a splattering of disconnected Facebook and Twitter posts. Historically I have had a positive response to my blogs but I have never been fully happy with the format. 

I really need to be able to post from my phone rather than laptop, just cause I move around so much so fast. Also the comments on Facebook posts have always been more active and dynamic than comments on the blogs, so now it should work where comments on the blog are done through Facebook. So, thanks to Dave Knepper at Rat, going to give this a shot.

And arriving in London now and

Let the games begin.  Oh, fun Halloween show at the Fonda Theater on Friday. Finally got a chance to mix on and did a visit of a tuneup on the V-Dosc/Rat Sub rig in there and it was awesome fun.

Forgot to take a PA pic but here are a few other pics from the show

Okey dokey, let’s see how this works and if all goes well, we will have an interactive flow of info where I can post and also answer questions or tailor a bit to requests 

Cool cool,