Carrie Underwood Sub Woofer Array

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John Vaneldik

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I posted this over at Prosoundweb and it was suggested that I post it here as well. If you have already read this in the other audio community I apologize for the double posting.

Tim McCulloch suggested that Evan Kirkendall might be able to shed some light on this. So Evan if your reading please chime in. Or anybody else that may have thoughts.

A couple of months back on the Carrie Underwood tour we set up an interesting sub array as follows.

There were 2 rows of 8, front loaded, 2 x 18 bowtie Clair subs facing each other about 2 feet apart. The boxes in each row were tight together (in my memory). These were all under stage right. It is my understanding from replies at prosoundweb that this is an end fire array. (Which is what I thought). I am wondering what the math is behind the spacing between the 2 rows. I assuming it is not arbitrary since the sub tech laid down a specially cut piece of plywood before we set each sub in place. The spacing as I mentioned was about 2 feet (I don't know the exact measurement however).

The sub tech was telling me that he could setup a hammock behind the array and hear very little (if any sub) during the show.

I walked around from backstage to out in front and there was indeed very little sub at the back and plenty of sub out front (as I would expect from an end fire array).

The sub tech then went on to explain that they could steer the subs by delaying the onstage row in relation to the off stage row.

I am hoping that someone could give me a more detailed description of the inner workings of this array.

I have been doing lots of research and calculations and for the life of me I cannot figure out exactly what is going on here.

Thanks in advance for any and all replies.

Happy mixing!
John Vaneldik
 
Re: Carrie Underwood Sub Woofer Array

As far as I recall, the spacing is dependant on what frequency you'd like to tune to array too, and the delay time on one side is what determines the directionality of the output. Please feel free to correct me if I'm wrong.
 
Re: Carrie Underwood Sub Woofer Array

John,

The spacing between subs in an end-fire subwoofer array (which is certainly what we're dealing with here) determines the maximum frequency that the array will be effective to. The overall length of the array determines the minimum frequency. By using two end-fire arrays right next to each other and slightly delaying one or the other, it is possible to steer the LF lobe the arrays generate... how much this matters depends a lot on the venue, array placement, and number of arrays in play. It is possible to generate 15-20dB of rear rejection, which when compared to the noise coming off the mains may very well make it seem like the sub arrays are off.

Here is an article I wrote on this very subject:
http://www.soundforums.net/content/152-Advanced-Subwoofer-Techniques
 
Re: Carrie Underwood Sub Woofer Array

017.jpg

This is the array that was used for the Godsmack tour. Bruce Reiter and Jeff Goode along with several other mixers can give you their thoughts on it's effectiveness. I personally loved it and would prefer this over any array shape I have ever used for sub . The coverage is amazing.
017.jpgThis is similar to the Carrie Underwood array. This is half as long but twice as high. And obviously in the air.

This is the array that was used for the Godsmack tour. Bruce Reiter and Jeff Goode, along with several other mixers, can give you their thoughts on it's effectiveness. I personally loved it and would prefer this over any array shape I have ever used for sub . The coverage is amazing. And you can blur your vision at 100 feet. I will not go into technical details here, but I can tell you how this started.
I had never used an array of this type. The goal was to get a more efficient array for the subs and to try to clean up the garbage onstage that is inherent in stereo stacked sub arrays. I was not sure if the flown array was going to have the kind of musical impact that I want for a heavy rock show. So I added the 4 subs per side on the ground and used them as a small centerfill pa. They were useful for putting the frontfill boxes on, because they never got turned on. The flown array had so much impact it was insane. But the band was asking if the low end was on. Perfect. The first time I had no points out in the house to fly the subs, they had to be stacked on the floor. The impact on the stage was huge. And not in a good way. Monitor mixes turned muddy, and the complaints started. This was from a heavy rock band that had gotten used to really good ear mixes because the pa wasn't interfering with the engineers job.

I think that non traditional sub arrays are going to be the way forward. The giant stack of low end boxes in front of the most expensive seats will be a thing of the past. And they should be if you really want to give everyone a good audio experience. It takes a little more work and you have to have some juice with the production to get them to agree to seeing this large thing there. And of course, listening to the local toolbags opinions about how subs were done in 1972.
 
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Re: Carrie Underwood Sub Woofer Array

Hi John-

I think in each column, subs were in pairs, with spacing between each pair as it went upstage. I recall the tech being less concerned about that spacing than the distance between the facing columns, and IIRC the distance between pairs was <1 ft.

As we were lining up the subs, I mentioned the end fire arrangement and our tech said "this one does tricks" and mentioned both pattern control and beam steering.

Clair's "A" level shows that come through here are carrying more drive processing than a couple of years ago and sub array tricks are only part of what they use 8 D.L.P. to accomplish.

I hope Evan finds this and replies.

Tim Mc

http://www.jblpro.com/catalog/support/getfile.aspx?docid=234&doctype=3 is Rick Kamlet's paper on "forward steered bass arrays" using a small JBL "install" product, but the concept scales up as seen in this paper: http://www.jblpro.com/catalog/support/getfile.aspx?docid=272&doctype=3
 
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Re: Carrie Underwood Sub Woofer Array

Hello John,

Coming to the party late...I believe Bennett has posted the relevant info.....but, was the Clair Tech... JOe Dougherty?

Cheers,
Hammer
 
Re: Carrie Underwood Sub Woofer Array

Preach on Frank!

Frank has things absolutely right as he used the same principles as we used on Carrie Underwood. We were looking for a system that provided a long throw application for the arenas as well as keeping the stage sound very controlled and this array absolutely was the best I have used. It's sonically pleasing as well as very controlled so that you do not have the sub freq rolling around behind the stage and in the empty part of the arena backstage. The keys to the array were the distance between the two lines of subs facing each other under the stage and the delays used between cabinets. With the Lab Gruppen PLM amps this was easily accomplished. We did indeed have a hammock hung from the upstage end of the array and one of our more industrious crewmembers caught 40 winks OR MORE during soundchecks and also sometimes the show itself. Now this was not a member of the Clair Crew of course. We were busy during the show! The distance between the two lines of subs determines where the cutoff point of the coverage. The wider the array the further back the low end will extend on the stage. We spent many days experimenting with different distances to determine where we needed to cut off the subs so as not to disturb the artists and yet still have coverage of the low freq up the sides for the audiences on the side. If we sold further back into the sidestage seats we adjusted for that. This arrangement is highly efficient as I was FAR below the output limits of the system for Carrie's tour. Because you are focusing the energy where you need it the subs do not need to be driven as hard. I hope this helps in the explanation of why and where we used the array the way we did and Frank's show by all accounts with Godsmack was nothing short of amazing each night and he used the system the way it's supposed to be used! I was happy to see him using this setup as it allowed his talents to get the last seat in the house and leave people feeling like that had just been to the show of a lifetime. It was remarkable and he chose the right tool to get the job done! So just when you think it's safe to get back into the muddy waters of audio and shows.......someone moves the subs!!! Cheers!!

Randy Lane
FOH/Carrie Underwood Play on Tour 2009/2010
 
Re: Carrie Underwood Sub Woofer Array

Tim McCulloch said:
http://www.jblpro.com/catalog/support/getfile.aspx?docid=234&doctype=3 is Rick Kamlet's paper on "forward steered bass arrays" using a small JBL "install" product, but the concept scales up as seen in this paper: http://www.jblpro.com/catalog/support/getfile.aspx?docid=272&doctype=3
Click to expand...
Tim,

I read those papers with much interest as well, but my real world experience has been that over- or under-delaying sounds bad and makes the off-axis pattern funnier than Rick's papers would seem to imply. Best results for me have always been with exactly the required delay. Maybe some day when I'm rich and famous I'll be able to work more on the results I've gotten, but for now it's just do it by the book for me.
 
Re: Carrie Underwood Sub Woofer Array

Simply offered as background, not a prescription
icon_biggrin.gif


I, too, disagree with the over-delay that Rick promotes, but I haven't had enough free time in large venues to compare objectively. Our shop isn't big enough to set up something like this and not get reflection contamination. Still, it's a good read and did what these papers should do: it made me think. I'll be back after I put some ice on the sprained brain cell... :lol:

So, are you still working with Fowler on a sub-array workshop for later this year?

Have fun, etc.

Tim Mc
 
Re: Carrie Underwood Sub Woofer Array

Frank,

Great photo! Center cluster of flown subs is like mecca for me, I'm drooling on my keyboard. I bet you had enough output, indeed, and very even coverage as well with less room excitation. Lets you run subs like your line array, and throw the majority of your energy towards the back of the audience. Kick ass.
 
Re: Carrie Underwood Sub Woofer Array

Bennett is on the money with his reply. I've only gotten to play with this array a few times, but it is very consistent, and works very well. The PLM20k's allow you to do whatever processing needed to make it happen. The rest is a secret. ;)



Evan
 
Re: Center Cluster Sub Woofer Array

Bennett Prescott said:
Frank,

Great photo! Center cluster of flown subs is like mecca for me, I'm drooling on my keyboard. I bet you had enough output, indeed, and very even coverage as well with less room excitation. Lets you run subs like your line array, and throw the majority of your energy towards the back of the audience. Kick ass.
Click to expand...

I have had good results with this center sub array.
 

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Re: Carrie Underwood Sub Woofer Array

Francesco Sgambellone said:
View attachment 714

This is the array that was used for the Godsmack tour. Bruce Reiter and Jeff Goode along with several other mixers can give you their thoughts on it's effectiveness. I personally loved it and would prefer this over any array shape I have ever used for sub . The coverage is amazing.
This is similar to the Carrie Underwood array. This is half as long but twice as high. And obviously in the air.

This is the array that was used for the Godsmack tour. Bruce Reiter and Jeff Goode, along with several other mixers, can give you their thoughts on it's effectiveness. I personally loved it and would prefer this over any array shape I have ever used for sub . The coverage is amazing. And you can blur your vision at 100 feet. I will not go into technical details here, but I can tell you how this started.
I had never used an array of this type. The goal was to get a more efficient array for the subs and to try to clean up the garbage onstage that is inherent in stereo stacked sub arrays. I was not sure if the flown array was going to have the kind of musical impact that I want for a heavy rock show. So I added the 4 subs per side on the ground and used them as a small centerfill pa. They were useful for putting the frontfill boxes on, because they never got turned on. The flown array had so much impact it was insane. But the band was asking if the low end was on. Perfect. The first time I had no points out in the house to fly the subs, they had to be stacked on the floor. The impact on the stage was huge. And not in a good way. Monitor mixes turned muddy, and the complaints started. This was from a heavy rock band that had gotten used to really good ear mixes because the pa wasn't interfering with the engineers job.

I think that non traditional sub arrays are going to be the way forward. The giant stack of low end boxes in front of the most expensive seats will be a thing of the past. And they should be if you really want to give everyone a good audio experience. It takes a little more work and you have to have some juice with the production to get them to agree to seeing this large thing there. And of course, listening to the local toolbags opinions about how subs were done in 1972.
Click to expand...

This is a VERY GOOD post indeed. Made me really happy to read this whole thread actually!

I've been working with this kind of arrangements for the past 6 months or so. Mostly 1 high ground stack version but 4 deep, 2 rows facing each other type of thing.

I've been using Nexo CD18 for several years and other cardioid subs (J-SUB, RS-15s/18s) for some time and I always thought there's something missing on the impact but never understood what's the matter. Later I went on designing more and more gigs with horizontal sub arrays and I was loosing the impact even more. My sub designs were very even when measuring frequency response anywhere in the venue but I had no impact left whatsoever.

After years of thinking these setups and working with different prediction softwares AND some discussions with Magu Ramirez from Meyer Sound I realized some key points. AT THE SAME TIME I've been working a lot with Nexo RS15 subs. The RS15s can be used as cardioid single boxes or as "regular"omni subs. When I combined my experiences with the RS15s with several years experience on sub array designs I felt like I've seen the light!

The gradient technique that is used to accomplish the cardioid effect in all (?) the single sub cardioid systems is killing the coherency (or punch or impact). Dave Rat has a good explanation about the "issue" in YouTube, unfortunately I couldn't find it quickly to link it here.I will not comment any theory side Dave might have in his video, but I remember when I first saw the video I KNEW IMMEDIATELY what he was talking about since I'VE HEARD THAT. I was so happy to see someone explaining something I've experienced also myself but could not explain it that well to other people.

I personally realized this down side with the gradient technique when I came to the conclusion with the RS 15s that they ALWAYS sounded better (coherent/punchy) when used in "omni"-mode than in any single box cardioid setup.

When I took my battle for more punch/coherence more seriously I went to center/mono sub configurations and started to use the subs facing each other. This way the area where the sound is originating is in its smallest and therefore has least cancellations = MOST COHERENT SUMMATION of transducers.

Later with larger setups I put these each other facing pairs into end fired setup and I was done. There is no return.
First larger setups I did in venues with capacity of 4000 or so I was blown away by the impact I heard. I never thought that could be possible in such large room.

One of the key points is that the point of origin is very small, making very solid/coherent impact. Also the subs used in these kind of setups sum very well with each other. I've actually have been able to reduce the number of subs needed for certain yearly gigs like fashion shows etc. when compared to previous years while having the same output but much better coherence/impact. These kind of setups can be varied quite well also by changing the distances between the rows facing each other and changing the distances between the subs in one row.

ANYWAY this thread has already been one of the best I've read for long time. I suggest anybody using the Nexo RS subs with NXamps to make an comparison at the warehouse or some other large space by putting 4 in cardioid mode against 4 in end fired setup. 4 in omni mode, on the floor facing same direction, one behind other, each one delayed (confirmed with acoustic measurement) the last one IAW . And 4 in cardioid alternate stack. You can feel the lack of impact and you will never go back.

If somebody will actually try this I'd be interested to hear the results.

-ville
 
Re: Carrie Underwood Sub Woofer Array

Tim McCulloch said:
http://www.jblpro.com/catalog/support/getfile.aspx?docid=234&doctype=3 is Rick Kamlet's paper on "forward steered bass arrays" using a small JBL "install" product, but the concept scales up as seen in this paper: http://www.jblpro.com/catalog/support/getfile.aspx?docid=272&doctype=3
Click to expand...
Nice:
I'd compiled a small list of related stuff a while back
http://billfitzmaurice.info/forum/viewtopic.php?f=18&t=8602
It's interesting ( to me anyway ) the parallels with antenna technology.

Great pics BTW
 
Re: Carrie Underwood Sub Woofer Array

Thanks Randy. You are the man. If you don't know who Randy is, you should. He has been doing amazing work for as long as I have known him. And I've been fortunate enough to steal the stuff I though could be useful. He is being far too kind to me here.I appreciate the kind words. As far as this discussion is going ,there was something else I forgot to add.

Because the coverage from the sub array is so wide (just shy of a full 180 degrees), this gives you the ability to make the side hangs really feel like part of the main pa. Any one who has tried to tune a system knows that it is difficult to get the side system to feel like it's not disjointed from the main arrays. The sub being directed into the side seating area helps "glue" the side hang into the main array. And even in the middle of the goalposts, the lack of cancelation areas makes the pa sound much smoother over a larger area. It just sounds way more musical. Our tour wasn't carrying side hangs and even having to add pa of the day when seating required it, it was much easier to get it to fill the sides with the full range of the pa. There are a lot of sonic advantages to this deployment.
It is a good thing that we are moving away from the old school. Ville, let me know if anything else come from you tests. Randy, also hits upon a major point. Efficiency. If you dont have to drive the subs very hard to fill a 12000 seat hall, you can start to minimize the number of elements. A win for everyone except the guys renting boxes I guess. The only place this gets tricky is the signal processing because it does require a lot of dsp to do things like this. And this means more money going into an area that no one really cared about before. It's not really practical to try and A/B two different types of arrays on a large scale, but in my case, Randy had already proved it could be done. What he was doing with Carrie's tour was like precision laser surgery. What I did with the PA was like a meat cleaver. However, the technology worked for both cases. We were both able to reproduce each of our respective artist's music with a common technology
 
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