Dave Rat - Roadies in the Midst

Sitting at out first real show with full production after doing the listen wanders. All American Rejects were on stage and I had my first chance to get a solid idea of how the Sub Vortex system is working. Yes, Scott, Vortex is winning like 30 to zero so far. Whatever. Anyway, we are pretty happy with the setup. The diagonal fire focus is really effective but a bit too wide of an angle. Rear and stage side cancellation is substantial. I am going to do one change next show and run them the opposite directions as I am calculating much better aim and focusing deeper to the rear of the venue. The time alignment comes up much cleaner with B and C being identical in delay and D at about double.

Plus the cancellation s are better aimed to the side and rear and it eliminates the D to B cancellation aimed into the audience center. I realize that for you tech head types, my drawings are probably shockingly over simplified and lack all the fancy colors and such, but hey, this is how I figure the stuff out, so I am sharing the raw methods.

Here are the actual shortest distances from acoustic center to acoustic center. Though in reality some of the path lengths are altered by the cabinets being in the way.

Grabbing the two approximate primary distances of 3.6 feet and 6 feet and taking a look at the effect on cancellations we should see behing and stage side of the array

We can see excellent rejection in the 50 to 70 range for our B to A and C to A combos (50 is mid way between green and yellow but not shown). For our 6 foot DC and DA combos we see the polars below which offer more control to a lower frequency. The DB polars at 4 feet read somewhere in between these.

All in all we are seeing a good amount of cancellation and due to the various combos, it should be a well spread attenuation rather than concentrated in a narrow frequency range.

The Listening System

Moving on, check this out! We have four pairs of wireless transmitters/receivers with high quality omni lavaliere mics attached. These Sennheiser units are the same systems that video cameras use for wireless audio on transmission/reception and the receivers are the same units that are used for in ear systems. And while I am at it, and for some shameless self promotion, if you need any Sennheiser or any audio gear for that matter, give Daniella a shout at the Rat office and she will hook you up with great deal. Ha, tell her you are a friend of Dave Rat!

And Nick the Fly with the mics and transmitters.

We can place these at various locations in the venue. Though the mics are not perfectly flat in response, they are close. Since the data I am looking for is simple frequency response, we have the four mics and a hardwired RTA mic all run into console channels. We have calibrated by placing them next to each other and set gains so they all read the same sensitivity. So now I can PFL any of the mics and see the response of that mic on the RTA. I do not really care if the read out is flat, what matters is that the mics give me an RTA reading that looks like RTA reading from the reference mic at FOH mix position.

So now, very simply I can see on the RTA and hear in my headphones various locations during setup and sound check and we don't have to run a bunch of stupid mic cables all over the place. So far we have not built housings for the transmitter so that they can live in the audience during the show, but we are pondering a method.

These reference mics give us the power to quickly figure out if the sub Vortex system is working as desired, are totally wireless and easily transmit the distances we are dealing with.

Oh, and just for the heck of it, here is a link to the SB28 owners manual.

http://www.l-acoustics.com/manuels/SB28_UM_ML_1.0.pdf

**** End Sound Nerd Speak ****

Hmmm, did I mention that the drum riser flies? And spins, and tilts and Travis rocks the house in a huge way. Really cool to see and I get to push those subs right on up to vision blur mode! Check out this sexy setup!

And to further soften the landing from all the heady sound nerd world, this is my shorty Sammy

This here would be my other shorty, Maddie and the cookie we made. Why make a bunch of little ones when you can make one huge one. Go big!

And hey, there Taco!

Nick the fly, me and hey, my dad, say hello papa Rat!

My friend for over 35 years, say hey to Brian Rat who started the company with me. We did a bit of surfing at San Onofre before I left.

Don't mess with Taco! He is my guard blog.

Next up, lasers and perhaps a new name suggestion has been put forward for the Vortex. This one may be a hard one to beat!

Dave Rat

It is quite a drive from Vegas to Vancouver so I stayed an extra day in Vegas got a bit of work done and a bit of fun done before jumping onto the bus adventure. All good, 3 hour flight lands 30 minutes early, we taxi up to the gate, well, not quite the gate. We can see the gate but pilot informs us that there is a bit of a lightening storm. While the storm poses no threat to us plane people, the airport has decided that the humans that normally cruise around in those squished looking airport vehicles should stay indoors till the storm passes. I woke up two hours later pulling into the gate. A quick dash down to customs and oh my. They have unloaded the entire airport backed up constipation of humans all at once onto a meager smattering of customs agents working overtime. I felt quite at home as it looked like the floor of a small but packed arena with the only exception being that my backstage pass is useless here. Zig zag lines that would give Disneyland a run for its money on a weekend. So funny to keep passing the same people, back and forth we go till at last, with a few too many questions and a stamp in my passport I am on my way.

Ooooh. Yikes, look at that taxi line. Double yikes as the 1/2 block long clusterfucks is aimed straight at a 2 little Prius Taxi's and every few minutes another zips in. "Is that really the taxi line?" "Nope, that is the the taxi line" Pointing to another 1/2 block line twice as thick that wraps around the other side of the road. "This is the front half."

Five motionless minutes spent at the tail end convinced me to seek a better path. Free hotel shuttles looked hopeful only for me to discover that they drag you to Airport hotels and I'm headed downtown.

Aaargh and then I see it. A small sign. "Public Transportation." A bit of a hike, a bit of a wait and on I hop. "I am sorry sir" eyeing my $20 canadian bill, "We only take change on the bus." But before I had a chance to ponder my next move, he goes on to hand me a bus pass, wave me on board and gesture to the next person in line to get on."

Welcome to Canada and I smile as not fighting the things beyond my control brought me in for a smooth landing. A very very slow, but smooth landing.

I must remember to have one of the hotel housekeepers teach me how to make a bed. How do they do it? It would take me half the day to get a bed to look like this! There must be some secret tricks or something.

Ok, back to **** sound nerd speak **** lest I get distracted, not that that ever happens.

Subs. So after all the various configuration were sifted, I narrowed to three with a distinct focus on one design that seemed most promising.

First though a bit about distance and subs. There is a magic distance when spacing subs for maximum forward summation and maximum rear rejection of 1/4 wavelength of the frequency that you want the most rejection to occur. The reason is that if you space them one behind the other 1/4 wavelength in distance and then time delay the front 1/4 wavelength, then in front they add together with minimal loss while behind they are effectively distanced at 1/2 wavelength. Since 1/2 wavelength is 180 degree out of phase, you get maximum cancellation at that frequency.

Which frequency you design for depends on your subs and other factors but typically 40 to 60 hz is pretty good. 1/4 wavelength of 50 hz is about 5.5 feet and a good place to start. That means that a five foot spacing from center of sub to center of sub, with the subs being around 4 feet wide, is about a 9.5 foot width with not much gap between them. The good news is that it is close to the size I am seeking for this design to fit under an 8 x 8 deck.

So far I do all my designs on paper with computer assistance only for drawings, based primarily on logic and experience and I do the math by mostly by hand. But hey, I mix on an analog console as well. But that does not mean I can not use computers to check my work, so I sent it off to Sugden to run some projections and see if I am on base and have taken all the variables into account.

The Spiral or as Scott Sugden came up with, The Vortex are the names I am considering. Have you noticed yet that I like to name things? A bit of fun and makes it easy. How about a vote? Spiral or Vortex?

Anyway, here is how it is supposed to work. There are four stacks of three SB 28's with two stacks facing forward (toward mix) and two stacks facing to the side (off stage).

Sub "A" stack is the primary drive on each side with stack "B" time delayed to increase level forward and cancel level behind. Stack "C" is time delayed "A" as well to increase level to the side and cause cancellation on stage. Stack "D" is time delayed to increase level at 45 degrees while canceling at 235 degrees.

All in all the primary array focus is 45 degrees and by increasing or reducing the level of stack C and some altering of delay times, the coverage can be narrower or wider. The interaction between "D" and "B" also adds somewhat at 200 degrees and cancels at towards stage. The "D" to "C" interaction is forward beneficial as well as "D" has the longest delay time.

The end result I want is a well diffused power alley, significant power to the deep diagonal throws of the arena, controllable side coverage, excellent rejection on stage and minimal overpowering of the people in front of the stage.

I know from experience that having two point sources for subs will cause some issues and I will get cancellations just to the sides of where power alley usually is. But, this should setup should be much better behaved due to the effective focus 45 degrees off axis. The combined response looks a bit like a butterfly.

To deal with gaining more control over power alley and help diffuse the cancellations off to the left and right of center, we are carrying 4 stacks of two Rat Super subs evenly placed across the front of stage. The time delay on these will be focused on FOH and the level can be varied to optimize.

To make these things easy to setup, Nick the Fly designed some inserts that our tour set carpenter made for us:

Fitted inside the wood aligners allow us to easily repeat the setup. Another wonderful aspect about this sub setup is the creation of a special little hang out spot for the sound techs in case they want to just get away from it all for a bit of relaxation, as Manny is demonstrating.

Having these ideas and projects is all good and fun but actually making them work properly is and testing how well they work is another challenge. So now it all about brainstorms and unraveling the fact from fiction with Nick the Fly. Nick and I have toured quite a bit together in the past and has been extremely involved and familiar with the progress of these concepts into reality over the years. Did you know Nick actually was the cabinet builder for many Rat designed boxes. I would send actual napkin sketches and he would build stunning enclosures.

As I mentioned, I personally am not so much a pretty picture kind of guy that keeps messing with software to try and find a coverage that looks good. Rather, I try and solve from a logical approach, try to confirm with the software and then do actual testing. Then, if logic, testing and software all agree, I gain confidence.

So to address the measurement side I have finally put together something Nick the Fly and I have been discussing doing for years now. How cool would it be to have a simple system where we could drop reference mics in various locations around the venue to monitor the sound without running a mile of mic cord everyday. A system that does not rely on trusting whether you are getting a correct reading from some super high tech measurement software. But rather a quick look and listen in real time.

Well, I will describe that some other day.

**** End Sound Nerd Speak ****

So if that was not enough thinking for you, I have a bit more. Jim, Nick the Fly and I were out for a wander and happened upon my very first Canadian yard sale. Hey look, speakers! I love speakers and upon closer inspection I began to poder a question and have a little test for you.

Ok, so there are these speakers in your car and you think to yourself, "hmmm, I want to take these speakers out and put in new ones." Now for the big question. Which tool do you grab out of the tool box?

A) The screwdriver with a square drive and loosen the screws

B) The 3/8" socket wrench and loosen the nuts on the back and remove the nuts

C) The oxyacetylene cutting torch and shoot flames into the inside of your gas powered vehicle

If you guessed "C" you are absolutely correct! For the rest of you, come on, think first before you do things.

Dave Rat

More Homework

So just as I did for the Coachella sub setup, I set a few goals and restrictions to see where that would take me with the design. And just as I did with Coachella, I have the honor of being able to run the designs by Scott Sugden from L'Acoustics who has the skills, experience and software to sort through the options. I really do feel fortunate to be able to not only try and figure out cool solutions but also to have the support people and sharp humans that can help me implement these things on a fairly large scale.

Lets start off by clarifying a simple rule of thumb regarding configuring speakers.

The wider you stack speakers horizontally, the narrower the coverage is horizontally. The higher you stack speakers vertically, the narrower the coverage is vertically. This is counter intuitive at first as it is tempting to stack speakers wider and wider to cover a wide room. When using horns and with mid and higher frequencies that can be easily controlled in their directivity, stacking wider for wider coverage can work well. But the rule of thumb is based on multiple speakers reproducing the same signal with their coverage patterns overlapping.

With sub woofers, overlapping coverage patterns are all but unavoidable, so the rule of thumb works well, especially with larger arrays.

OK, so the premises I am following are:

1) Horizontal sub arrays reduce horizontal coverage and create a power alley in the room center reducing coverage to the sides. - I need to keep the sub arrays compact horizontally.

2) Vertical sub arrays tend to reduce vertical coverage. A flown vertical sub array further messes up vertical coverage due to the reflection effect. I will try to keep the subs on the ground.

3) A stacked vertical sub array is a bit more forgiving in its vertical coverage than a flown array. Yet more concerning is that the tall ground stack in an arena will usually block sight lines unless it is behind the band, and we surely do not want the band in front of the low end I am going to dumping on the audience. Keep the sub array compact vertically.

4) A stage center horizontally ground stacked sub array blasts the front row of humans and tends to arch over backwards onto the band. Even with a cardioid sub array placed stage center, my experience is that, having the singer just a few feet from the primary subs generating enough lows for an arena creates an inevitable mess. Avoid putting lots of subs stage center.

5) The setup must be easy, repeatable and be able to cover the venues without the time consuming tedium of meddling with multiple interacting delay times every day. I want two or three clean presets that I select from. Maybe a 180 degree coverage, a 220 degree and a 270 degree. Create a sub setup that allows changing coverage without re stacking.

6) Finally, as with any useful idea, the less negative side effects, the better. So the sub array ideally should not reduce venue capacity, block sight lines, push out the barricade, look ugly, or cause any issues for backline, lights, video or any other department. Plus it would be really cool if it was easy and fast to setup.

Hmmm, that really tilts toward putting subs on the floor and off to the sides as the best of the options without diving into an some esoteric 3 dimensional flown sub arrangement that would change the rules a bit. In order to reduce the power alley effect, creating a sub woofer setup where each side has a bit of reduced coverage in the room center should help.

Anyway, based on those parameters and keeping in mind the quality of the overall show as whole, the most finessefull solution seemed to be to refine the sub cannon design for added control and improved coverage. Reducing the quantity of forward facing subs towards the stage middle would be good as well.

Here is the Peppers sub configuration drawing for the 2006 -2007 tour

And a picture of it

I will also need to account for the fact that I will be using the L'Acoustics SB28's rather than the Rat subs I had on Peppers tour. I love the Rat subs and with the new Rat Super Sub, the added power is awesome. But Rat Sound has the privilege of being one of only two vendors with a K1 system in North America during this pilot phase of the K1 system release so both Rat and L'Acoustics really are focused on keeping it all intact as a complete system so we can really learn the rig and share what we experience with the manufacturer. That is not to say that it can not be augmented, but for the primary system it is all about a matched L'Acoustics rig.

So I am going to walk the line between off the shelf L'Acoustics with a bit of optimization based on my past experience and setups.

Picture time. This is pretty much the way I start projects. First establish a rough goal based on fulfilling the need or solving a flaw to what is existing. Next start drawing pictures and try and cover all possible permutations regardless of whether they are feasible or not. I then sort through the pictures and weed out the weak ones, hopefully settling in on a small range while weighing the assets and issues. Finally refine, redraw, build and test the winners out.

Just to give you an idea of some of a few of the 20 or so layouts I went through, here are some really rough stage right sketch's that did not make the cut for this tour.

The Fan. This would have the rear three at zero time and a delay added to the front three. I never ran projections as it was too big for what I am working on here.

 

The Focus. With all the work on the design of the EAW MicroSub, I have been diving into and using mechanical coupling arrangements, this is a triple sub setup seemed interesting. The delayed center can be timed to steer the coverage a bit. Never tested it and it seemed to be too limited in control.

Two behind three. This is a 12 x 12 foot and cumbersome. But perhaps you can see where I am headed with attempting to have control over the forward fire, diagonal fire and side fire while offering some cancellation on the stage and behind the subs where the monitor position and techs will be.

The Quad. The size is getting better and with subs pointing forward and to the right combined with delays it could offer some control. I really want power delivered about 45 degrees to the right of center. That tends to be the longest shot in an arena as well as a place where people will not be really be too close to the subs due to sight lines.

The Circle. Similar, and though you often hear that subs are omni directional, it does not take a rocket scientist to walk around the back of a subwoofer and hear that they are a bit louder and more direct sounding in front. This sub circle could have all subs facing inward or in several differing directions.

 

The Split. The next one actually is pretty good and fits in an 8 by 8 foot area. I could time delay it it for a 0 degree, 45 degree or 90 degree focal point. A bit light though, I was hoping to get 12 SB28's per side and to match the stage height so I am looking at 3 per stack. Meaning this is a 9 sub array. The sub on the right would add power to the side while offering some cancellation on stage. The sub up top in the drawing adds power forward and cancellation behind. the interaction between the top and right subs should cause some cancellations to the upper left power alley area and lower right 135 degree off axis area. By messing with levels a bit, the coverage could be altered a bit. Plus the distances are hovering around that magic 1/4 wavelength of 60 hz range which is useful for cardioid sub configurations.

Oh, and let me not forget the most important part. The Carpet.

How can we possibly do a rock show without a nice fuzzy carpet to stand on!

Next up, more subwoofery stuff, some simple cool measurement tools and running it old school style.

Dave Rat

Here we go Blink 182 and cool rock show. I have not really figured out my direction yet as far as blogging and adventures but in the mean time, I may as well rock on the tech side of things. Will work on losing my mind later.

The Los Angeles Forum was the playground for testing and getting things dialed in.

So what is new for this tour? Well, the new K1 rig is a monster! Truly some breathtaking horsepower, V-Dosc with nitro boost. Aside from the significant jump in clarity, it can pump enough low end from the main hangs to make the subs almost optional.

Similar to the Peppers rig, I am once again using an 8 foot by 8 foot sub array with a blow through aluminum grate on top that doubles as stage wings. It is a really cool way to go as it gives me a lot of freedom with the sub design without eating up valuable floor space while keeping the setup clean visually. My goal once again is to attack the issue of whimpy low end off to the sides of stage and while gaining control over how much power alley there is.

For those non-soundy humans, power alley is the term used to describe the area down the center of the venue where the low end tends to be more powerful than elsewhere. So in itself I guess a 'power alley' is good for the humans hanging out there but that also means that everywhere else is not a power alley. For some odd reason, it has become a commonly accepted practice to have a strong power alley. Personally, though I love the low end power, I really work hard to get the sound as consistent as possible throughout the venue. Forget power alley, I want a Power Valley and I want everyone in it!

Easier said than done. Turns out that if you stack horizontal sub arrays on the left and right sides of the stage, they will be loudest midway between them while off to either side of center the low end drops off quickly. One solution is to put all the subs in the middle which works fairly well and also tends to completely wipe out the band on stage with low end. Also, the center sub thing tends to really smear the heads off the humans parked in the front rows.

Another method that is becoming more common is to fly vertical line arrays of subs. This solves the blasting the front row humans issue quite well, offers improved low end off to the sides and a more reasonable power alley. The issues are that the vertical sub line arrays create these cancellation nodes that project like spokes just to the left and right of audience center. The cancellation nodes can be quite pronounced to the point where there are areas with almost no sub right next to areas with powerful sub sound. Another drawback with flown subs is that they create a sideways power alley. By that I mean that there is a power alley effect that offers strong low end at floor level that tapers off as you increase in altitude. You see, the floor acts like a mirror to subwoofers. When you stack subs on the ground, the subs are sitting on the mirror, in effect doubling the energy radiated.

Just as power alley occurs in the horizontal plane (wide vertical, narrow horizontal) with subs stacked side by side on either side of the stage, a vertical power alley is created when subs are flown in a vertical line (narrow vertically, wider horizontal) caused by the interaction between the flown sub array its reflection in the mirror (floor). Since power alley is in effect most pronounced for the locations horizontally equidistant from the subs, with a flown sub line array, the subs are loudest for humans vertically equidistant from the subs and their reflection. In other words, there are challenges in the vertical coverage with the center of power alley at your feet dropping with elevation. For a flat field show this is not really an issue, and can be an asset but in arenas and venues with humans up high, the reduced vertical coverage can be a significant issue.

Several years back I was doing a show where the sound vendor swore up and down that we needed to fly subs. Even after I killed the idea, I was surprised to not only find that they were flying subs when I arrived, but they went on to tell me they were going to fly twice as many. Why? Well, they went on to explain that they were having trouble getting low end into the balcony area of this huge indoor sports venue. After a bit muscle flexing and much to their dismay, I pressed the issue, made them drop all the subs and we ground stacked. I then personally walked the balcony with the head sound tech during the support act. "Better?" I asked. He was quite surprised and fully agreed that the subs to the upper sections issue was solved. The price? Well, I had power alley back in the horizontal again which meant the lows dropped to the sides. But for that venue which was not very wide, the percentage of people that heard solid low end was significantly increased.

Alright, time to fly, more to come tomorrow as I try and regain some bloggery momentum.

 

Dave Rat

Oh so many things going on. Probably the most life affecting adventure for me coming up is a 10 week US tour with Blink 182. Ten or so years ago, I was mixing Blink 182 as they grew from clubs to arena's before returning to do a Peppers tour. Here we are a decade later and it is pretty cool to join them again for a North America shed and arena run. We are going to be moving fast and covering lots of ground with over 40 shows.

So what is the plan rubber band? I have been putting some thought into sound, as one in my position would and pondering what if anything outside of the norm I could or should do. The double hung PA worked amazingly well on Peppers and I am a bit remiss to return to a single hung system.

But hey, each band/tour has unique aspects and based on the dynamics at hand, I have different plan this time out. But, while we are speaking of double hung PA's though, check this out!

 

U2 is doing a stadium tour in the round. Check out that PA, notice anything? There are 3 PA hangs, 2 hangs of Clair full range boxes inside and a hang of Clair subs to the outsides.

Well alright, U2 is touring with a double hung PA, how cool is that! Well actually that would be four double hung PA's. My good friends MC and Paddy who are out with Snow Patrol were kind enough to give me the low down. And yes, it is truly being run the same way as we did on the Peppers with the vocals in one system and the instruments divided between the two systems. That rules, the largest tour in the world right now has a double hung PA! And the desire to shout "see, I am not crazy after all!" while running around doing a naked victory dance is very tempting.

But back from the past, lets look at now and Rat has this cool new L'Acoustics K1 rig that I know is louder and clearer than V-Dosc. Blink is an energetic fun rocking band, so from a sound perspective, I am going to approach it from a clean and simple angle. Nope, no double hung this run. I am excited to take the K1 toy out and see what it can do in a conventional setup before I go getting all wacky with concepts. I am thinking that the new K1 system and it's added clarity and volume, may be able to give the double hung V-Dosc rig a run for it's money.

But I get bored to easy not to do something special so I have been working some sub layout designs, trying to fine tune and improve the sub cannons so if your interested in that sort of stuff, I will post more on later. Also, I have finally put together a little system for measuring venue acoustics in various locations so I can see setups and coverage works as predicted.

In the mean time, the storm before the calm sets in as I realize some sad goodbyes and bearing down upon me. October! , yikes, wont be home till October, that is a rough concept to get my head around, anyway, my little pals that are gals that are going starting high school before I get home.

Meet Taco the little dog pal my daughters have convinced to adopt me and has been hanging tough and keeping my company.

And without looking back cause it hurts my heart, off and away for many days in far away places.