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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB: The Classic Live Audio Board => Topic started by: John Vaneldik on February 25, 2011, 09:47:21 pm

Title: Sub Array Layout
Post by: John Vaneldik on February 25, 2011, 09:47:21 pm
Gentlemen (and Ladies),

A few months back I did an IA call for the latest Carrie Underwood tour and was intrigued by their sub array layout.

Basically what they did was the following:

Under stage left were two rows of Clair 2 x 18 subs (front loaded). These two rowss faced each other and were about 2 feet apart. They applied the necessary delay to each box (in each row) to align them with the upstage most sub in the line. They could then manipulate the onstage row delay (as a group) in relation to the offstage row delay to steer the subs.

My questions are these:

How did they calculate the distance between the two rows? It wasn't arbitrary, because the sub tech set down a specially cut piece of plywood before we set each cabinet in place (in order to get the spacing right).

I assume that the length of each row (i.e. the number of cabinets in each row) was not arbitrary either. How did they calculate this?

Can some one shed some lighton this?

TIA
John


Title: Re: Sub Array Layout
Post by: Tim McCulloch on February 25, 2011, 11:16:37 pm
Gentlemen (and Ladies),

A few months back I did an IA call for the latest Carrie Underwood tour and was intrigued by their sub array layout.

Basically what they did was the following:

Under stage left were two rows of Clair 2 x 18 subs (front loaded). These two rowss faced each other and were about 2 feet apart. They applied the necessary delay to each box (in each row) to align them with the upstage most sub in the line. They could then manipulate the onstage row delay (as a group) in relation to the offstage row delay to steer the subs.

My questions are these:

How did they calculate the distance between the two rows? It wasn't arbitrary, because the sub tech set down a specially cut piece of plywood before we set each cabinet in place (in order to get the spacing right).

I assume that the length of each row (i.e. the number of cabinets in each row) was not arbitrary either. How did they calculate this?

Can some one shed some lighton this?

TIA
John

It's an endfire array.  Bennett Prescott has a couple of articles on sub woofer arrays, Harry Brill has written on them, and Arthur Skudra has commented on the forums, too.  A search will bring up a bunch of info.

I was an IA hand when the show came through my town, under the stage setting the dress, couch and other stuff that came up on the lifts.  It was nice not being pounded by the LF.  There was a program feed down there from monitor beach, and the vocals were "unprocessed."  I'll leave it to the reader to guess what that means. ;)

Have fun, good luck.

Tim Mc
Title: Re: Sub Array Layout
Post by: John Vaneldik on February 26, 2011, 12:12:45 am
It's an endfire array.  Bennett Prescott has a couple of articles on sub woofer arrays, Harry Brill has written on them, and Arthur Skudra has commented on the forums, too.  A search will bring up a bunch of info.

I was an IA hand when the show came through my town, under the stage setting the dress, couch and other stuff that came up on the lifts.  It was nice not being pounded by the LF.  There was a program feed down there from monitor beach, and the vocals were "unprocessed."  I'll leave it to the reader to guess what that means. ;)

Have fun, good luck.

Tim Mc

I thought it was a form of end fire array. But it seems different than what I've seen before. Actually, I am sitting beside one right not. The funny thing to me is that there was no space between the cabinets front to back. But there was space between the two rows side to side (about 2 feet as I mentioned).

I did a search on end fire arrays and found all sorts of information. But none of it seems to discuss quite this layout. I will keep searching and pondering.

Thanks Tim!

Happy mixing!

John
Title: Re: Sub Array Layout
Post by: Steven Norman on February 26, 2011, 08:11:16 pm
I thought it was a form of end fire array. But it seems different than what I've seen before. Actually, I am sitting beside one right not. The funny thing to me is that there was no space between the cabinets front to back. But there was space between the two rows side to side (about 2 feet as I mentioned).

I did a search on end fire arrays and found all sorts of information. But none of it seems to discuss quite this layout. I will keep searching and pondering.

Thanks Tim!

Happy mixing!

John

John,

Have a look at this link:
http://www.electrovoice.com/sitefiles/downloads/wp%20-%20Subwoofer%20Arrays%20v04%20.pdf (http://www.electrovoice.com/sitefiles/downloads/wp%20-%20Subwoofer%20Arrays%20v04%20.pdf)

Its a document off the EV website titled 'Subwoofer Arrays: A Practical Guide'. It provides a good insight into the world of different sub arrays and positioning.


Steve
Title: Re: Sub Array Layout
Post by: Sheldon Harris on February 27, 2011, 09:03:12 pm
The funny thing to me is that there was no space between the cabinets front to back. But there was space between the two rows side to side (about 2 feet as I mentioned).


what do you mean no space? no, as in none, 0, this seems interesting, takes some pics, how does it sound behind the array?  maybe i should have asked how the front sounded first ;D

sheldon
Title: Re: Sub Array Layout
Post by: John Vaneldik on February 28, 2011, 01:58:35 pm

what do you mean no space? no, as in none, 0, this seems interesting, takes some pics, how does it sound behind the array?  maybe i should have asked how the front sounded first ;D

sheldon

When we set them up the subs had no space between them. Keep in mind that the fronts of the cabinets were facing each other. There were two columns/rows (depending on your terminology) and they faced each other about 2 feet apart.

As far as I know that is where they stayed.

When I moved from backstage to out front near the end of the show there was very little sub behind the sub array and plenty out front.

John
Title: Re: Sub Array Layout
Post by: g'bye, Dick Rees on February 28, 2011, 02:37:01 pm
When we set them up the subs had no space between them. Keep in mind that the fronts of the cabinets were facing each other. There were two columns/rows (depending on your terminology) and they faced each other about 2 feet apart.

As far as I know that is where they stayed.

When I moved from backstage to out front near the end of the show there was very little sub behind the sub array and plenty out front.

John

John.....

I still have no idea how the cabinets were oriented.  Can you somehow do a drawing????

Thanks
Title: Re: Sub Array Layout
Post by: David Morison on March 01, 2011, 07:43:30 am
I still have no idea how the cabinets were oriented.  Can you somehow do a drawing????
Thanks

Hi Dick,
I think this is what is being discussed (assuming the cabs were stood upright).
Cheers,
David.
Title: Re: Sub Array Layout
Post by: Frederik Rosenkjær on March 01, 2011, 11:13:22 am
Hi Dick,
I think this is what is being discussed (assuming the cabs were stood upright).
Cheers,
David.

I also couldn't really figure out the original description. If I understand the picture correctly it's a sort of tunnel of subs under the stage firing first under the drummer then out towards the front of the stage?

But then I can't make sense of the "assuming the cabs stood upright"-comment...??
Title: Re: Sub Array Layout
Post by: Tim McCulloch on March 01, 2011, 11:46:59 am
I also couldn't really figure out the original description. If I understand the picture correctly it's a sort of tunnel of subs under the stage firing first under the drummer then out towards the front of the stage?

But then I can't make sense of the "assuming the cabs stood upright"-comment...??

This discussion also taking place on 'another' forum.  The linked pic shows a flown variation.

http://www.soundforums.net/attachment.php?attachmentid=714&d=1298952956

The thread also contains some additional reference material.

Have fun, good luck.

Tim Mc
Title: Re: Sub Array Layout
Post by: Iain.Macdonald on March 01, 2011, 12:26:44 pm
Hi,

For the o/p, have a look at this paper from JBL (http://tinyurl.com/26rmus5) about their FSA(Forward Steered Array). Somebody has obviously had better luck persuading a company to try this concept. I tried some years ago, and all I got was disbelieving stares. Oh well. Hope this helps.

Iain.

Title: Re: Sub Array Layout
Post by: John Vaneldik on March 02, 2011, 02:30:51 am
David,

That is exactly what is being discussed, except that there were 8 subs in each row. I also started a thread on soundforums.net. On that board Randy (Carrie's FOH guy has joined the discussion) and there are pictures of a similar flow version on a Godsmack tour.

I am very excited about where audio is going with concepts like this.

John

Hi Dick,
I think this is what is being discussed (assuming the cabs were stood upright).
Cheers,
David.
Title: Re: Sub Array Layout
Post by: David Morison on March 02, 2011, 08:22:26 am
I also couldn't really figure out the original description. If I understand the picture correctly it's a sort of tunnel of subs under the stage firing first under the drummer then out towards the front of the stage?

But then I can't make sense of the "assuming the cabs stood upright"-comment...??

Hi Frederik,
The "tunnel" description is about right, though from the OP I think there was one such setup each side of the stage rather than a single central one.

My comment about the cabinets being upright was in reference to the fact that I only show one driver in each as if you were loking down on a 2x18 from the top - just because it was quicker to sketch up that way rather than doubling the number of drivers per box in the pic.
Cheers,
David.
Title: Re: Sub Array Layout
Post by: Peter Morris on March 03, 2011, 01:56:39 am
This discussion also taking place on 'another' forum.  The linked pic shows a flown variation.

http://www.soundforums.net/attachment.php?attachmentid=714&d=1298952956

The thread also contains some additional reference material.

Have fun, good luck.

Tim Mc


The flown array could be described as an end-fire dipole.  In the horizontal plane the end-fire arrangement gives a cardioid type pattern.  In the vertical plane, its a dipole and the bass directed towards the stage a roof will be reduced…. perfect !

Peter