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[Kevin.Windrem]

Art Welter wrote on Sun, 26 April 2009 11:11

Mac, I would think the ceiling height would be as important as the wall relationship as far as LF room response. It appears you can specify room floor dimensions, but what is Mapp deciding to make the ceiling height? Art Welter

I'd agree floor and ceiling make a major impact. However, MAPP works in two dimensions only. You can model a side view response with floor and ceiling or a plan view with walls but not both and there's no way to combine the results.

[Mac Kerr]

Art Welter wrote on Sun, 26 April 2009 14:11

Mac, I would think the ceiling height would be as important as the wall relationship as far as LF room response. It appears you can specify room floor dimensions, but what is Mapp deciding to make the ceiling height? Art Welter

Mapp does not do 3D calculations. It can only model the centerline plane of the speaker or speaker array. For this reason it cannot show you a plan view of the coverage of a vertical array.

Mac

[Nick Aghababian]

What are the advantages of a vertical sub array?

[Mac Kerr]

Nick Aghababian wrote on Sun, 26 April 2009 15:23

What are the advantages of a vertical sub array?

Since you neither quoted nor responded to the message you seem to be addressing, what are you talking about? There is nothing about vertical sub arrays in Ivan's message.

Mac

[Ivan Beaver]

Nick Aghababian wrote on Sun, 26 April 2009 15:23

What are the advantages of a vertical sub array?

As with everything there are advantages and disadvantages.

Among the advantages: Same horizontal dispertion as a single unit-ie wider coverage.  With a tall enough array, less energy will go up in the air where it is not needed and energizing less of the reverberant field.

Among the disadvantages: Blocks sight lines if ground stacked, hard to get stacked high up (takes more time-ie labor), by narrowing the vertical you may not reach the seats that are high up-same problem as the seats on the sides in my post.

Unless flown, you cannot get a tall center array.  Tall side stacks will exhibit various "finger lobes" based distances between stacks and varies with freq.

There is no "free lunch".

[Scott Smith]

Ivan Beaver wrote on Sun, 26 April 2009 19:15

...There is no "free lunch".

Ummm...

[Ivan Beaver]

Scott Smith wrote on Sun, 26 April 2009 21:47

Ivan Beaver wrote on Sun, 26 April 2009 19:15 ...There is no "free lunch". Ummm...

Ok, maybe not everybody WANTS a free lunch   Some things are better if paid for

[Phillip_Graham]

Mac Kerr wrote on Sat, 25 April 2009 17:46

How the array behaves is very dependent on frequency. It is also very dependent on the environment. The difference delay makes with no walls is easy to understand, and seems very controlled. When you add in the reflecting surfaces of the room the whole picture changes. It is easy to see why it is not so easy to make this all work in the real world. Mac

Hey Mac,

Two points of subtlety, even though the point of these graphs should not be lost on anyone.

First, MAPP gives no consideration of the third dimension, which can/will change the locations of the nodes and antinodes,  The diagrams can be thought of only as accurate in 2d.

Second, MAPP gives you no control of the stiffness and losses of the room boundaries.  I don't know the values that Meyer has chosen, but they may or may not reflect reality.  Simple (ie unrealistic) boundary conditions is typically computationally expedient, so that might be what Meyer is doing.

I am sure Perrin or one of their other modeling guys could chime in on that.

[Michael Hedden Jr.]

Am I the only person that sees a guitar bridge?
Chord.....It's been a hard days night..

Mike Hedden
Danley Sound Labs, Inc.

[Mac Kerr]

Phillip Graham wrote on Mon, 27 April 2009 15:06

Mac Kerr wrote on Sat, 25 April 2009 17:46 How the array behaves is very dependent on frequency. It is also very dependent on the environment. The difference delay makes with no walls is easy to understand, and seems very controlled. When you add in the reflecting surfaces of the room the whole picture changes. It is easy to see why it is not so easy to make this all work in the real world. Mac Hey Mac, Two points of subtlety, even though the point of these graphs should not be lost on anyone. First, MAPP gives no consideration of the third dimension, which can/will change the locations of the nodes and antinodes,  The diagrams can be thought of only as accurate in 2d.

True, I think I mentioned that here.

Phillip Graham wrote on Mon, 27 April 2009 15:06

Second, MAPP gives you no control of the stiffness and losses of the room boundaries.  I don't know the values that Meyer has chosen, but they may or may not reflect reality.  Simple (ie unrealistic) boundary conditions is typically computationally expedient, so that might be what Meyer is doing. I am sure Perrin or one of their other modeling guys could chime in on that.

Mapp does give you some control over the surface as shown in the image below. What I have not been able to make it do is make the architectural guidelines be surfaces. As far as I can tell you are limited to the box shape, although you can set the dimensions of the box. Since it is not 3D those details may be irrelevant anyway.

Mac

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