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Thoughts on ceiling treatments w/ line arrays? [message #23557]

Thu, 15 March 2007 21:37

Aaron D
Messages: 18
Registered: May 2009

Chancellor

I have an idea for a ceiling treatment panel that was originally inspired by one of those home decorating shows and my lack of satisfaction w/ the current lighting in my room.

Room is 11 X 17 and I want to hang a 4'ish X 6'ish panel from the cieling centered in the room. My arrays will be 1' to 3' out from one of the 11" walls. That puts the top of the arrays 4.5' to 2.5' from the closest edge of the panel.

With any other type of speaker I would not even worry about the effects, but knowing that the arrays we discuss on this board actually benefit from floor and cieling reflections makes me wonder if I might be working against myself. I can accomplish the design part of this project more easily if I do not try to make it an acoustic panel also so this project does not hinge entirely on this aspect. It was just an idea I had and I saw a way to kill two birds w/ one stone potentially.

Any thoughts?

Aaron D

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Re: Thoughts on ceiling treatments w/ line arrays? [message #23563 is a reply to message #23557]

Fri, 16 March 2007 10:31

Wayne Parham
Messages: 18784
Registered: January 2001

Illuminati (33rd Degree)

As long as the ceiling doesn't buzz, it's good. A little bit of "give" helps damp room modes. In this regard, line arrays are particularly immune to floor and ceiling reflections because of the differences in path lengths between individual drivers and the floor and the ceiling.

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Re: Thoughts on ceiling treatments w/ line arrays? [message #23564 is a reply to message #23563]

Fri, 16 March 2007 10:47

Bill Wassilak
Messages: 402
Registered: May 2009

Illuminati (1st Degree)

That and the vertical dispersions only going to be 5-10 deg at most.

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Re: Thoughts on ceiling treatments w/ line arrays? [message #23567 is a reply to message #23564]

Sat, 17 March 2007 10:34

Wayne Parham
Messages: 18784
Registered: January 2001

Illuminati (33rd Degree)

Even at very low frequencies where the line becomes a point source, there is still response averaging from reflected path length differences. The end drivers in a 5 foot line are 1/2λ apart at 112Hz and 1/4λ apart at 56Hz. So those two will cancel at 112Hz but others in the line will fill in the response at that frequency. The same kind of thing happens to reflected modes coming from the floor and ceiling, although the distances will be greater since the floor and ceiling are spaced away from the line. This makes the frequencies lower where the averaging modes occur. A 5 foot line acts like a point source below 56Hz since every driver is 5 feet apart or less. But reflections may be greater than this distance. Still, the number of drivers tends to average the field, in the same way the 112Hz mode from the two most distant drivers are averaged by the drivers in between.

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Theory is great... What do I do with it? [message #23569 is a reply to message #23567]

Sat, 17 March 2007 14:10

Aaron D
Messages: 18
Registered: May 2009

Chancellor

I understand what you are saying but how can I apply it? From what I can gather it does not seem as if my panel will have much of an effect one way or another. It could possibly be of benefit at lower frequencies but I am pretty sure that a panel the size of what I had planned will start losing effectiveness well before getting down 100 Hz. I might keep it in mind but I will concentrate on other places for room treatment. Like I mentioned before the whole panel idea was more of a decorating/lighting improvement idea originally.

Thanks,
Aaron D

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