conquistadore
Forum Moderator
Joined: 03 Aug 2004
Posts: 513
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| Line Arrays |
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Whats the concept behind line arrays? |
Mon Nov 07, 2005 1:37 pm |
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baguio
Tape Op
Joined: 16 Sep 2004
Posts: 25
Location: Baguio City, Philippines |
i would simply say it brings better sound derectivity to the audience than conventional types. new look perhaps!
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Sun Dec 17, 2006 2:11 pm |
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amitbarde
Forum Moderator
Joined: 24 May 2006
Posts: 79
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Well baguio you are quite right. The line array system does provide directivity. But what you have to understand is WHY IS THERE A NEED FOR THIS DIRECTIVITY?....
It's quite simple really.....it's all to do with hearing (Varun would know a lot more about this than me).....we hear sounds better and clearer when they are incendent on our ear drums in a more direct way...which means a sound should hit you like a beam which will ensure that all or a most of the content will be delivered clearly to you. Conventional sound delivery systems tend to disperse sound over a wide angle horizontally (meaning, theire wave front are quite large as those compared to the ones from the line arrays) which results is poorer clarity.
Also you must have noticed that the line arrays have a "J" shape when they're hung. This again is for the sole purpose of directivity. Imagine a football stadium with a band playing at one end and people in front as well as the rafters behind. How will all the people get the same quality?...here's where the "J" shape of the line array comes into the picture. The curve of the J will direct sound towards the audience at the front of the stage while the cabinets at the top will disperse the same sound to the rear. And since line arrays are designed to be directive, the people sitting behind will receive the same sound albeit a little softer (remember the inverse square law still spplies here...which means, to deliver the same loudness more power would be required). Also, importantly the line arrays reduce/eliminate the need for a delay stack. How is this possible?......quite simple actually.....the cabinets dispersing sound to the rear of a venue have some delay applied on them depending on certain calculations (time = speed of sound/distance). Quite a simple technology but then again, not so simple!
The other thing that adds to the directivity of a line array system are the compression drivers (for the highs usuallly). i don't quite understand how it works with the other drivers but a compression driver is known to keep the path of sound quite "straight". The other advantage line arrays have is that minumal sound is dispersed behind the system hence increasing efficiency.
Threre's also something to do with the wavelength and the distance between each cabinet. You could read more about line arrays on JBL's website (they have the best line arrays i've heard!!!..the vertec series....very crisp and clear).
Also other websites which give you more information on line arrays are linearrays.com
renkus-heinz.com
martinsound.com
....and few others i can't recollect right now.
Hope this has been useful. |
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Mon Dec 18, 2006 1:09 pm |
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wailingalleycat
Forum Manager
Joined: 07 Oct 2003
Posts: 694
Location: Jersey C.I (UK) |
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quote:
read more about line arrays on JBL's website (they have the best line arrays i've heard!!!..the vertec series....very crisp and clear).
Wow Amit..Very Controversial! Go listen to some MeyerSound MILO/M-Series then come back and tell me Vertec sounds better!
There are also some physical advantages that you missed out. Line arrays are flown from the rig, thereby eliminating the need a for large PA wings, freeing up more of that precious stage space. and as they arent on the floor, they arent transmitting nasty vibrations through the stage.
Another thing is as they are high up, they can get better dispersion across the audience. for the same effect you would need a very tall ground stacking PA to clear the heads of the audience and other obstructions (sound/lighting booth for example)
And lastly, the boxes are smaller so take up less room in the truck.
Disadvantages anyone?
the ones that spring to my mind are the cost to buy the array and the time needed to plan the installation then tune each section of the array. but we can safely say that Line Arrays are becoming the norm for large scale concerts.
-Paul
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Last edited by wailingalleycat on Mon Dec 18, 2006 2:20 pm; edited 1 time in total |
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Mon Dec 18, 2006 2:07 pm |
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conquistadore
Forum Moderator
Joined: 03 Aug 2004
Posts: 513
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| Line Arrays and directionality |
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Yeah, Amit, you are right. Except for one thing: the inverse square law (which states that with the doubling of distance the sound level drops by 6dB) does not apply for line arrays. If I'm not mistaken, instead of the level dropping by 6dB with the doubling of distance, it drops by 3dB. This is due to their directional properties. Since they are more directional compared to conventional output transducers, less energy is 'lost' by dissipation in directions other than that necessary. Conventional speakers dissipate sound energy in a more or less spherical shape - but its more beam like with line arrays.
And yeah, since a larger part of the system is made of horns, the directionality increases. Horns (compression drivers) are known for their directionality, having Qs (referring to Q of the boundary effect) greater than 50. |
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Mon Dec 18, 2006 2:18 pm |
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amitbarde
Forum Moderator
Joined: 24 May 2006
Posts: 79
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Yeah Varun...i forgot about that!....thanks for putting that in...i hope more people are actually goin through these things....maybe we could start some other discussions too....these seem to be very informative.... |
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Mon Dec 18, 2006 2:23 pm |
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wailingalleycat
Forum Manager
Joined: 07 Oct 2003
Posts: 694
Location: Jersey C.I (UK) |
Well thats the plan amit...
if you have any suggestions go right ahead and start a discussion and we will all chip in. 
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If In Doubt...Hit It With a Hammer, If Still In Doubt... Find a Bigger Hammer. |
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Mon Dec 18, 2006 9:03 pm |
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