Rational Acoustics



Kip Conner
February 3rd, 2009, 06:57 AM
I'm seeing a trend in manufactures to make wider and wider coverage compact line array systems. Will someone please tell them to stop? I'm trying to do a design where size, weight and directivity are the main factors (plus cost, so milo 60's are out of the question) and everything is 100 degrees or more.

I need a system that is 60 degrees, but I would be willing to go 90. The walls aren't buying a ticket- they don't need to hear it.

Sorry for the rant.

Harry Brill Jr.
February 3rd, 2009, 08:00 AM
I'm seeing a trend in manufactures to make wider and wider coverage compact line array systems. Will someone please tell them to stop? I'm trying to do a design where size, weight and directivity are the main factors (plus cost, so milo 60's are out of the question) and everything is 100 degrees or more.

I need a system that is 60 degrees, but I would be willing to go 90. The walls aren't buying a ticket- they don't need to hear it.

Sorry for the rant.
I tend to agree.

Check out the GEO S12 and S8 They are quite powerful and the directivity of the horn can be adjusted. The S8 can be 80, 100 (asymmetrical), or 120. I think the S12 comes 80 and if you want to widen the coverage you have to buy the CDDs. I use a 120 on the 30degree vertical (bottom) box. The down fill sounds slightly different, but it beats the heck out of the alternative for the near field. If you have any questions about these, email me.

Arthur Skudra
February 3rd, 2009, 08:04 AM
The challenge in designing a *compact*, narrow horizontal coverage line array is achieving horizontal directivity. The less wide the box is, the poorer your pattern control becomes in the horizontal plane, the laws of physics are at play here, particularly at the low frequencies. Bigger line array boxes have greater space to integrate a decent sized horn for the HF & MF. In order to maintain a consistency in coverage throughout the frequency response of the box, many manufacturers attempt to pattern the HF coverage to follow the LF coverage so that spectral consistency is maintained for the box. Measure it for yourself, columnar and mini/compact line arrays ALL suffer from poor control of the horizontal coverage in the LF! Some line arrays do better than others (eg. Nexo Geo).

Furthermore, the way most line arrays are deployed (left-right) a wider horizontal dispersion helps with center front coverage, at the expense of greater overlap at the center rear, and added spill on the side walls. The big implication here is not to locate FOH along the centerline of the room. Depending on the grazing angle with which the line array hits the side walls, I consider reflections off side walls to be less an issue than the distracting echoes heard from rear walls and balcony faces. It's all about managing your compromises!

Langston Holland
February 3rd, 2009, 10:20 AM
Hi Kip:

EAW got enough requests like yours for the KF730 series (110 degrees horz), and responded with the KF737 (75 degrees horz):

http://www.eaw.com/products/KF730.html

http://www.eaw.com/products/KF737.html

sweepableQ
February 15th, 2009, 05:50 PM
Check out the d&b audiotechnik Q series for a narrower pattern in the horizontal.