Dave Rat - Roadies in the Midst

Hmmm, wondering if the L-Acoustics K1 Coachella system be referred to in the male or the female context. What do ya think? I can think of some big reasons it could go either way. Though I am tending towards pushing the feminine angle and so with that said, how about we take a good look at her bottom end?

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RATED Triple N (Must be an advanced nerd to read)

Quite a bit of thought was put into the subwoofer setup for Coachella Main Stage. I had the honor to work with Scott Sugden from L'Acoustics on the subwoofer design and it was really fun. The first thing we did was outline the goals to be achieved:

1) The design must be appropriate looks and location wise. By that I am referring to avoiding an awkward sub setup like one that pushes the barricade out too far or those super tall sub stacks that block video screens and look terrible. The goal is for speakers to be heard, not seen and if it is seen, it should look clean and fit into the look of the stage.

2) The design must be repeatable. I wanted to avoid a 'custom Coachella setup' that relies on taking advantage of unique aspects of the event or placement locations. The goal was to design a sub configuration that could be dropped into any field show and archive impressive results.

3) The design must be scalable. This is pretty simple to hit, but important none the less.

4) The design must be simple to implement. I wanted to avoid a setup that requires taking a bunch of complex time consuming measurements and extensive onsite testing that requires blasting subs for an extended time frame. We want simple, easy and very little room for error.

5) The design must have flexible dispersion/coverage capabilities. One of the coolest aspects of the sub cannon setup I used on Peppers tour was that I could easily widen the sub coverage pattern by increasing the level of the side firing boxes. If the arena sold farther around the sides, I could easily increase the coverage to well beyond 180 degrees. For the Peppers field setup with sub cannons, I could widen and narrow the coverage. We wanted to retain that flexibility while improving other aspects.

6) The design must not involve destructive sound. By that I mean that I did not want any boxes that are used to cancel out sound. Out of polarity rear firing speakers used create cardioid patterns are an un acceptable solution. I also wanted to avoid that whole beam steering thing where a whole bunch of graduated delay times are used to electronically focus. One or two delays I am fine with, but beyond that, too scary and my experience with electronic beam steering is it is one of those 'two steps forward and one step back' scenarios where side effects of db loss and complex coverage patterns negate many of the advantages.

7) The system must be able to convert to conventional sub woofer setup without moving speakers. There will be over 30 engineers mixing on the system at these festivals and we need a setup that will make everyone happy, so it needs to be able to switch to a normal-ish sub setup, should any engineer so desire.

8) The subwoofer coverage of the event must be impressive. The big challenge with subwoofers is that you are fighting two main issues. First is that the wider the subwoofer setup is, the narrower the coverage is. Secondly, the reduced horizontal coverage issue can be addressed by stacking the subs into two tall vertical arrays BUT, those vertical arrays cause these huge V shaped cancellation nodes. If you have mixed on a system with vertical subwoofer arrays, I am sure you have noticed those huge holes just to either side of power alley where there is practically no sub lows. To me, that is an unacceptable ramification.

9) The design must utilize the L-Acoustics SB28 sub woofers. Hey, they are part of our new K1 system and we are keeping the whole deal together and matched up and these subs are awesome!

10) The design should minimize low end bleed onto the stage. On a show this size where we are pumping low end over long distances, it is critical that we can deliver the needed energy deep into the audience with out overpowering our musical friends on stage just a few yards away from the subs.

So as the ideas bounced back and forth, it began to evolve in what seems in retrospect to be the obvious path. Lets combine the SB28's cardioid configurations with a version of the sub cannon configuration.

Before I go on, it is important to note that the L-Acoustics cardioid sub setup does not implement out of phase sound to cancel the rear propagation. Rather, it the rear firing sub is set at zero time delay and the front fire subs 'wait' for the sound of the rear sub to wrap around and then augment that sound. That means that in front of the cardioid array, all 4 boxes are in correct time. But as you walk around behind the boxes, the is a time error increases. This causes an effective cancellation behind the boxes while in front of the boxes it is all in time and good, hence 'cardioid.' Basically it is the same concept as the sub cannons except it requires less physical depth.

So the first thing we did was run some analysis on the arena and field sub cannon setups as well as numerous other interesting and cool sub layouts that Scott has implanted and pondered. What we ended up with is a 6 cluster setup. The primary cardioid sub cluster consist of 6 forward facing and 2 rear facing SB28's set at what we will refer to as 'zero time delay.' The next set of clusters had acoustic centers located 1/3 of a 40 hz wavelength to the outside of that. These outside clusters are the 'cannons' and are laid back in time by 1/6th of a wavelength at 40 hz, such that they augment the sub energy radiated 33 degrees off axis and create a cancellation on stage. These outside clusters consisted of 4 SB28's forward with 2 rear facing.

Finally, there are two small 2 box cardioid clusters just to the left and right of center. These serve two purposes. They act as center fill subs to even out the low end hole that created by being off axis to the main subs and also they act allow us to widen power alley and create an extremely smooth subwoofer coverage.

So maybe that sounds complex or maybe not but either way, the result is simple. Turn up the outside clusters and the coverage expands wider, turn them down and it becomes narrower. Turn up the center sub cluster and the power alley effect is reduced, turn them down and power alley increases. All this was achieved with only two very time delay settings and well thought out but simple stacking locations.

Ha! Well hopefully that got your mind spinning!

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While were are diving into all kinds of cool and exiting stuff, check out the MicroWedge 12 Case design. What do ya think? A one human operation to open and close the case.

Plus storage inside for cables, tripod mounts and MicroLegs means the case is fully self contained with all you need after the amp.

Here is the bottom storage, there is another compartment up top as well.

 

I am not through yet, much more to come, like a whole series of arm reach self photos with cool Rat crew and the rock stars of the sound nerdery world. And lastly but not leastly, I would like to mention a new drink that a few of the sound crew has come up with. Vodka straight shots followed quickly with a Vodka straight chaser. Gotta be quick though and hit the chaser before the burn of the shot sets in and be sure to use two different kinds of vodka. Ha! Just kiding or maybe not.

Dave Rat feeling a little mini road fun that I so miss and so happy to be hanging with 'my people.'.

Ooooh, check out the sexy picture of main system for Coachella:

Here you can see the mains and side hang systems and also the 6 cluster subwoofer setup as well. There are quite a few new implementations of innovative theories in the design of the K1. The actual purpose and importance of the K1 Subs in the array is something that people are having a tough time getting their head around and I must admit that early on I was thinking "Why get any K1 Subs and not just buy more K1's, do we really need a third box type?" That was even further reinforced when I heard how much low end the K1 's can reproduce without any subs.

So what do these dual 15" boxes that are identical in size to K1 bring to the table and why do we need them or want them? Heck, for the most part, they are just K1 boxes with the mids and highs missing and I find their existence very interesting. In the mid 90's V-Dosc was new and the only large-scale line array on the market. Then, over the years nearly every major manufacturer has since staked their claim in the line-array bombardment of products. Each attempting some rehash and to add an asset to set themselves above the fray and to be honest, some really nice systems have come out of it by building upon the perceived starting point set by V-Dosc.

So taking a layman's look a line array theory, it basically says that the higher you stack up speakers the more control you can gain over the vertical coverage. With this vertical coverage control, you can do some interesting things like point more speakers far away and less speakers closer. This is cool because you can make it so that it is nearly the same volume far away as it is up close. Iimproving volume consistency throughout the listening area is a huge asset and we like huge assets.

In fact, a line array can be set up such that the volume level stays the same, even as you get farther away. Ahhh, but like everything in audio and life, obtaining something so desirable comes with a price to pay. Up to now line array designers have been addressing the entire audio spectrum with full range boxes plus subs. But the demands of the lower frequencies in the line array vary drastically from the demands of the higher frequencies. To put it in maybe something easier to visualize, the wavelength of the lowest notes we hear are about as long a one of those big rig tractor tailor trucks, including the motory part where the driver sits. The highest notes we humans hear have a wavelength maybe somewhere around the width of your thumb. Hmmm, how many thumb lengths to a big rig?

Anyway this vast differential in the wavelength creates many challenges. One of these challenges relates to the physical length a line array need to be to gain control over the various frequencies. Higher frequencies with short wavelengths only need a small vertical dimension while lower frequencies need an array of a much longer dimension. This is one of the fundamental reasons for the K1 sub. It allows the lower frequencies to have a longer line array length and and help match the coverage/throw of the lows to the mids and highs. Though this concept is natural and logical to line array design, it has been overlooked completely by all the line array emulations. But if the future follows the past, not for long as I am sure other companies will be soon to scramble to follow as it works way to amazingly well to ignore.

In fact the 'low throw' worked so well that we are rethinking the way we implement delay clusters. The natural absorption of HF by the air means sound will get duller with distance and so far, this means that for huge gigs the need to put up delay cluster is un avoidable, but since the K1 has the ability to present a clean tight controlled low end over much longer distances, the demand upon the delay clusters is reduced to only needing HF and perhaps a bit of mids. Running smaller, less obtrusive delays is a very cool thing cause we all know that setting up delay clusters is a pain, screws with sight lines and running low end into delays gets messy because it is so hard to control directivity. There is also another application for K1 subs as well but that will have to wait for a another day.

In the Sahara dance tent we set up mini sub cannons for the 2 side clusters and 2 rear clusters to get cardioid control and reduce bleed to other stages. This was the first year that we had no complaints about Sahara's sound stepping on the other stages. These are 1/4 wavelength at 50 hz spacing and time aligned for forward projection. Plus there is the added benefit of becoming a wonderful stacking surface for the V-Dosc. Say hey to Ronnie!

Not only was this the largest outlay of K1, ever in the world to this point in time, I also think it was the worlds largest outlay of EAW MicroWedge's with at least 50 or so. MicroWedge's did 4 of the 5 stages flawlessly!

So fun and more to come!

 

Dave Rat

Coachella is massive and magical. For sure by now if you follow world of musical news, you have heard at least two things about Coachella 2009. "Paul McCartney played a legendary two and half hour show and the sound was shut off after the Cure went ten minutes over curfew. And surely too, each of these two event descriptions were peppered with some form of journalistic opinions. The heart wrenching moment of Paul's song dedication to his wife on the anniversary of her passing and of The Cure continuing to rock some of their biggest hits to tens of thousands while drenched in a time stopping sonic silence. So being that the there is so much to tell of this weekend's desert adventure, it seems so most logically right to describe it in the wrong direction and start from the end.

Arms in the air eyebrows raised in bewilder, I look at MC, the sound engineer from The Cure and one of the best audio engineers I know. And while his band continues to play, in my normal speaking voice raised above non existent sound I apologize. There was no other option. With the polo field equivalent of house lights on, the band continues to play song and another and another in the surreal time stoppingly endless state we are trapped. "What happened?" Yet the answer we already know, it is the "why" that is still unfolding. Police on the radio's demanding a stop to sound from the massive stage, a promoter trapped in the middle between threats of cancelled future festivals and a crowd of multi thousands and a band playing harder than ever oblivious to the un deniable absence of 350,000 watt PA system pumping their tunes into hungry ears.

"Oh tragic" says the articles, debacle and mishap tossed around as if some huge error was made.

What really did happen? Did the promoter ruthlessly shut of the sound? Was there some behind the scenes conspiracy? Did the band accidentally play past some deadline unaware? Did someone forget to inform someone else or was a mind changed mid stream? Or perhaps, just perhaps, The Cure in their punk rock playfulness, decided to test the limits with a smile just because they can. Just to un bore the masses from their own lives by giving those that wish to say, like me, something to talk about. Mystique, stories and press exploding from the event lifting the notoriety to new levels beyond the quite impressive performance itself.

But as far the putz who threw the bottle at the sound board, come on, don't be so shallow as to miss the enjoyable complexities of the bigger picture, you missed the gear but it was close and hey, you could have hurt someone!

**** Sound Nerd Speak ****

Though in the music world, the incredible performances by too many bands to name will keep blogs and articles buzzing, there was something even more significant that occurred at this Coachella, at least from a sound nerdery perspective. I know what you are thinking and yes, it is true. The Coachella Main Stage saw the the unveiling of the largest L-Acoustics K1 system ever assembled. In my honest and true opinion, I now feel it is confirmed that this PA is truly the newest, latest, greatest and best sounding large scale sound system in existence. Never before have I heard such an overwhelmingly positive response. Not only from the world class engineers we had the honor to work with but from the promoter and humans in general. I am tempted to try and describe it further but it feels too awkward and since hearing is believing I will stop and leave the opinions to others to create.

I know I have been sluggish at blogging and I will try to get back to the enjoyable patterns I miss and left behind. You see, behind the silence and bloggery smiles, I have been immersed in taking on the most challenging financial project of my life. You know when you watch Texas hold'em poker and they get to the end of the game and there is that "all-in" bet? Well, for Rat Sound to get this K1 system, it was kind of an all-in plus all the futures of all-in's for a while to come like an all-in of all all-in's. And hey, I do my fair share of stupid stuff and the best I can tell I can be so good enough at messing things up that I have it covered for a few other people as well, but then there are things that are clear and there is no doubt in my mind and I know must be done right. Purchasing the K1 system was one of those things. When Jon Rat came to me and told me about it coming out, I was skeptical, when Jon arranged a trip to France to hear it, I was skeptical, when I heard it and what it can do I knew there was no alternative. This is the best and we must have it. The fact that the planet earth was in the largest economic down turn since the great depression was just an annoyance. A really big scary and challenging annoyance. And in a nut shell, that is where my mind has been, in a nut shell.

Anyway, you are looking 8 K1 subs, 15 K1's and 3 dV-Dosc per side in the main hangs and 8 K1's plus 3 dV-Dosc per side in the side hangs. On the ground are 32 SB 28's set up as cardioid subs with some Sub Cannon timing (you can't see the 4 subs in the middle). I hope to get into more detail at some point as the setup is super cool with new and refined concepts. The only issue we ran into was that the K1 has such a clean and wide coverage, the side hangs were too wide. I am confident the KUDO would have been a better choice but we used them all in the Mojave tent. Anyway, I hope to dive into all that in the coming weeks.

Oooooh, look at the size of that thing! The whole 'banana' term that is used to refer to line arrays is going to need to be re though. That is one big hang at nearly 40 feet in length

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Okey Dokey. Sleep and stuff and mental preparation for Stage Coach festival next weekend! Ha, I am so happy to be doing gigs. And speaking of gigs, I took a short little tour in the UK and Europe in May.

The finally getting out and about again,

Dave Rat