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Author Topic: When is it a line-array?  (Read 10909 times)

Robert Lunceford

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When is it a line-array?
« on: July 27, 2014, 09:50:18 pm »

I'm sure most of us have seen from one to three line-array "elements" mounted on a pole over a sub, or on a tripod stand as shown in this video.
http://www.youtube.com/watch?v=QZu8deHi6Ug
The DVA series are a very popular choice.
When there are only 2 or 3 "elements" stacked, will it actually perform as a line array?
If not, will it perform more like a point source speaker? How would we realistically expect a stack of 2 to perform?
I looked at the DVA spec sheet which includes the following specs:
Frequency Response [+/- 3dB]: 80 - 19.000 Hz
Directivity: 100x15 Single unit

At what range of the frequency response can we expect the 100X15 degree directivity? I wouldn't expect this directivity for the full frequency range of a single cabinet.

Do any of the professional audio societies have a published standard that defines what a "line-array" is?
I'm wondering how many "elements" you would need before the system actually begins to perform as a line-array.
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TJ (Tom) Cornish

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Re: When is it a line-array?
« Reply #1 on: July 27, 2014, 10:00:20 pm »

I'm sure most of us have seen from one to three line-array "elements" mounted on a pole over a sub, or on a tripod stand as shown in this video.
http://www.youtube.com/watch?v=QZu8deHi6Ug
The DVA series are a very popular choice.
When there are only 2 or 3 "elements" stacked, will it actually perform as a line array?
If not, will it perform more like a point source speaker? How would we realistically expect a stack of 2 to perform?
I looked at the DVA spec sheet which includes the following specs:
Frequency Response [+/- 3dB]: 80 - 19.000 Hz
Directivity: 100x15 Single unit

At what range of the frequency response can we expect the 100X15 degree directivity? I wouldn't expect this directivity for the full frequency range of a single cabinet.

Do any of the professional audio societies have a published standard that defines what a "line-array" is?
I'm wondering how many "elements" you would need before the system actually begins to perform as a line-array.
What do you mean by "performs as a line array"?
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Tim McCulloch

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Re: When is it a line-array?
« Reply #2 on: July 27, 2014, 10:03:32 pm »

I'm sure most of us have seen from one to three line-array "elements" mounted on a pole over a sub, or on a tripod stand as shown in this video.
http://www.youtube.com/watch?v=QZu8deHi6Ug
The DVA series are a very popular choice.
When there are only 2 or 3 "elements" stacked, will it actually perform as a line array?
If not, will it perform more like a point source speaker? How would we realistically expect a stack of 2 to perform?
I looked at the DVA spec sheet which includes the following specs:
Frequency Response [+/- 3dB]: 80 - 19.000 Hz
Directivity: 100x15 Single unit

At what range of the frequency response can we expect the 100X15 degree directivity? I wouldn't expect this directivity for the full frequency range of a single cabinet.

Do any of the professional audio societies have a published standard that defines what a "line-array" is?
I'm wondering how many "elements" you would need before the system actually begins to perform as a line-array.

To be a mathematical line source, it needs to be infinitely long.  That presents problems with my truck pack. ;)

The use of 2, 3, or 4 line array elements is a way to make more use of the investment, not a pursuit of audio excellence.

The DBTechnologies T4 is a model I have some experience with.  The 100 horizontal is consistent with itself regardless of how many boxes you line up, and the HF vertical dispersion of a single box is 15 give or take a degree or 2.  What happens in the vertical as you go down in frequency is determined by the length of the line, and so far I don't like the way anything <6ft long sounds, pretty much regardless of brand.

It's not about how many, but how long.  Ask your significant other... /nudge, wink, satire.
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Robert Lunceford

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Re: When is it a line-array?
« Reply #3 on: July 27, 2014, 10:11:56 pm »

What do you mean by "performs as a line array"?

Hi TJ,
As described in this paper written by Meyer.
http://www.meyersound.com/support/papers/meyer_line_array.pdf
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Jay Barracato

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Re: When is it a line-array?
« Reply #4 on: July 27, 2014, 10:25:21 pm »

I just spent 4 days at a festival where the stage we were on had 2 baby martin LA boxes on stands per side. This was the first time I gave ever really been happy with that configuration.

Not my system so I have no idea if there was anything really special in the processing but I was able to step up and just do my show and all the eq I really needed was the channel.

Sent from my DROID RAZR HD using Tapatalk

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Jay Barracato

Tim McCulloch

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Re: When is it a line-array?
« Reply #5 on: July 27, 2014, 10:37:11 pm »

Hi TJ,
As described in this paper written by Meyer.
http://www.meyersound.com/support/papers/meyer_line_array.pdf

What part of it are you finding most significant?  This was Meyer's response to another brand's marketing claims.

Note, too, that some of the things discussed in the white paper have been addressed by subsequent design advances from several manufacturers (including proprietary designs by that "Global" company that used to be Brothers).

I'd further direct you to some AES papers by Mark Ureda (EV, Altec, JBL) https://www.jblpro.com/ProductAttachments/AES_Ureda_Analysis_of_Line_Arrays.pdf (warning, heavy math lifting) and https://www.jblpro.com/ProductAttachments/MSU_AES_Fall_2001_Monday_Morning.pdf along with http://www.jblpro.com/pub/tour/aes%20may%2001%20ureda%20line%20arrays.pdf and David Scheirman's paper http://www.jblpro.com/pub/tour/scheirmanaes.pdf  You might want to look at Mark Engebretson and Doug Button's work, too.
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Robert Lunceford

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Re: When is it a line-array?
« Reply #6 on: July 27, 2014, 10:57:25 pm »

To be a mathematical line source, it needs to be infinitely long.  That presents problems with my truck pack. ;)

The use of 2, 3, or 4 line array elements is a way to make more use of the investment, not a pursuit of audio excellence.

The DBTechnologies T4 is a model I have some experience with.  The 100 horizontal is consistent with itself regardless of how many boxes you line up, and the HF vertical dispersion of a single box is 15 give or take a degree or 2.  What happens in the vertical as you go down in frequency is determined by the length of the line, and so far I don't like the way anything <6ft long sounds, pretty much regardless of brand.

It's not about how many, but how long.  Ask your significant other... /nudge, wink, satire.

Thanks Tom,
If the HF vertical dispersion of a single box is 15 degrees, I can see that a single box can be useful as a front fill. But what about 2 boxes on a pole? What practical purpose would you use this deployment for? It seems you would have to be careful how high up they are. If they are above the audience you may not be able to hear a good balance of HF to LF unless they were angled downward.
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Tim McCulloch

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Re: When is it a line-array?
« Reply #7 on: July 27, 2014, 11:31:37 pm »

Thanks Tom,
If the HF vertical dispersion of a single box is 15 degrees, I can see that a single box can be useful as a front fill. But what about 2 boxes on a pole? What practical purpose would you use this deployment for? It seems you would have to be careful how high up they are. If they are above the audience you may not be able to hear a good balance of HF to LF unless they were angled downward.

Tom will be along shortly.... ;)

How much vertical HF does the application require, and will the HF outrun the low-mids and lows?

Yes, aiming is important, and entire software programs are dedicated to predicting array coverage so the user can optimize coverage as he sees fit... but yeah, "point the speaker system at the listeners" still applies.

BTW, one of the things Meyer talks about that is often overlooked is how much LF is radiated behind the array.  This creates some interesting interactions with certain types of venue architecture (barrel vaulted ceilings and high trim heights...)
« Last Edit: July 27, 2014, 11:33:49 pm by Tim McCulloch »
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

Robert Lunceford

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Re: When is it a line-array?
« Reply #8 on: July 28, 2014, 12:03:38 am »

Tom will be along shortly.... ;)

How much vertical HF does the application require, and will the HF outrun the low-mids and lows?

Yes, aiming is important, and entire software programs are dedicated to predicting array coverage so the user can optimize coverage as he sees fit... but yeah, "point the speaker system at the listeners" still applies.

BTW, one of the things Meyer talks about that is often overlooked is how much LF is radiated behind the array.  This creates some interesting interactions with certain types of venue architecture (barrel vaulted ceilings and high trim heights...)
Hey Tim,
My apologies on the typo of your name.
If you had two of these boxes per side with a pair of their companion subs, how large of an area could you reasonably expect to cover?
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Scott Holtzman

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Re: When is it a line-array?
« Reply #9 on: July 28, 2014, 12:12:22 am »

Tom will be along shortly.... ;)

How much vertical HF does the application require, and will the HF outrun the low-mids and lows?

Yes, aiming is important, and entire software programs are dedicated to predicting array coverage so the user can optimize coverage as he sees fit... but yeah, "point the speaker system at the listeners" still applies.

BTW, one of the things Meyer talks about that is often overlooked is how much LF is radiated behind the array.  This creates some interesting interactions with certain types of venue architecture (barrel vaulted ceilings and high trim heights...)

Which is a great time to bring something else up.  Where do compact line arrays fit in?  Vue especially has been showing off the al-4, these things are tiny, 5.5" tall and when flown in a large array go in packs of 8 so that would  give you pattern control down to about 400hz. 

Is the compact line array all about beamforming or I am completely missing the point.  In the demo the show them stacked 4 on a sub for a club and on up.

Is this another trend or is some science behind it? 

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ProSoundWeb Community

Re: When is it a line-array?
« Reply #9 on: July 28, 2014, 12:12:22 am »


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