Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Guest]

[Mike Babcock]

Hey Phill

If one had the space, they can add more sub lines, 3 deep, 4 deep, etc and have more cancellation in back and more addition out front. It will also give a wider frequency range of add and cut because there is more than one spacing between boxes affecting a different frequencies. In theory the first delayed line reduces the fundamental frequency, the next line cuts the fundamental frequency plus the frequency half that (or twice the wavelength) and so on.
Work is fun again

Mike

[A Man]

Excellent post Mike!
You'll have to give me a tutorial of MAPP when we get a chance.

Even though I had the luxury of flown subs, it looks like this would have been a good thing if it was implemented at NEC-Birmingham or that London show we did.

Great job guys!!

[Josh Evans]

Phill wrote:

"Mike also could have placed the two subs back to back (i.e. speakon to speakon) and then delayed the front boxes. Or if the box was deep, like a SB1000, he could have stacked them vertically, turning every other one facing backwards, then apply the delay."

I like this approach better than the others, for rigging, and for keeping the polarity consistent.

The BDEAP-32 (afaik) isnt really a flyable box, meaning youd probly have to add tracks to it.  I only know of one job where they have been flown, and dont remmeber much about it.  

Just so yall know

http://www.ada-acousticdesign.de/english/e_online/index_onli ne.html

http://www.ada-acousticdesign.de/EaseMapsonline/EaseOnline1. aspx

EASE online can do the exact same thing as MAPP, and more!  

and dont forget.
http://www.ifbsoft.de/
FREE demo!!!

The thing to keep inmind is that with some of them youll have to use higher frequencies and scale them down.  This is because acoustical prediction programs dont do very well with frequencies bellow 100Hz.  Theres way too many variables!

[Mike Babcock]

For those still interested. I have created a MAPP file for my real life deployment. Like I said it's not as great as I would have liked, but a 'helluva' lot better than the original plan.

If anyone has any questions or comments, I would love to hear them.

Mike

[Tom Reid]

I'm following this thread, and I think I've absorbed about %90 of it.

Can I ask, when you fly subs, what do you need to deal with as far as the "Z" axis?  How does cardiod work "up there"?

[Mike Babcock]

Tom Reid wrote on Tue, 04 January 2005 21:25

I'm following this thread, and I think I've absorbed about %90 of it. Can I ask, when you fly subs, what do you need to deal with as far as the "Z" axis?  How does cardiod work "up there"?

It works just like a single cardioid pair. I have attached yet another MAPP shot for you.



The only problem I have with MAPP is that it gives you 2 axis, it is not a 3-D modeling system, so you can look at it as length and width, or length and heigth, or any other combination of 2 axis. My original plots were as if looking down on the stage, the one in this post is as if looking at the stage, height and width (or length). The cardioid array will act as a cardioid array in all axis. If you look at the array from behind the box or directly in front of the box, it would look like a single sub, if you look at it from the top, bottom or either side it will have the same pattern, the pattern just gets wider as the array becomes wider, or taller as the array gets taller (depending on your perspective). Make sense yet?

Mike

[Tom Reid]

Thanks Mike.
Yeah, that's what I was looking for, the lack of a 3D view.
One can assume the sub is going to play the same in the Z axis as the X axis I hope.

When you fly subs, can you get lost in the detail trying to point the null lobe down and back onto the stage?

Just a mental experiment.  I don't think I'll be big enough to ever fly subs in my little corner of the world.

[Guest]

[Eytan Gidron]

gtphill wrote on Mon, 03 January 2005 22:23

For those unfamiliar with the "cardiod sub" technique, let me explain what is done processing-wise.  The rear row of subwoofers is delayed to line up with the spill from the front ones.  The rear boxes have inverted polarity.  The result is that the waves cancel in behind the two rows of boxes, and sum coherently in front.  The wavelength of maximum cancellation is a function of the front-to-back driver spacing.  The longer the spacing, the lower the frequency.

Thanks Phill for this explenation. I am not sure that I got it right. Can you get a bit more specific - can you give an example with actual numbers (such as which delay time to which spacing, which frequencies will it affect?)

Will this method work well with horn loaded subs (such as the Turbo subs)?

[ProSoundWeb Community]