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JBL 4645
12-26-2007, 07:11 AM
While reading the "Sam I am" thread I realized something, what is the (horizontal and vertical) dispersion of the JBL control 5 and control 1?

So I would like to know please what widest horizontal dispersion is and the narrowest Vertical dispersion is?

Thanks.:)



:happyh::window:

Zilch
12-27-2007, 01:38 PM
What do the specs say?

Generally, dome tweeter = no control.

JBL 4645
12-27-2007, 02:58 PM
What do the specs say?

Generally, dome tweeter = no control.


Zilch

The specifications don’t say anything, I was hoping someone, might have some insider information on this? Thanks.:)
:happyh::window:

hjames
12-27-2007, 06:29 PM
Zilch The specifications don’t say anything,
I was hoping someone might have some insider information on this? Thanks.:)


No no - Zilch was pretty clear -


Generally, dome tweeter = no control.

Thats pretty straight-forward; when there is no structure around a dome, sound will generally travel the same in all directions. Think of a pebble tossed in a open pond - rings travelling outward equally.
When there is controlled dispersion, usually there is some kind of shaped horn or structural device. Think of the 2405/077 Slot tweeters, or the SAM horns array - each of them is tall and skinny, that slot-funnel shape is going to limit the expansion of the sound waves more in one dimension than in the other.

JBL 4645
12-28-2007, 06:05 AM
I never thought of that ripples in water thanks Heather :), so if I had a 18” ball of concrete and dropped into a lake, the ripples will be large is that what you’re saying??
:happyh::window:

hmolwitz
01-01-2008, 07:26 PM
Went to Alaska and watched the glaciers calving, nice ripples when the big chunks dropped.

doyall
01-04-2008, 08:30 AM
These folks seem to disagree about dispersion characteristics on dome tweeters. It appears as though they claim they can control it through the crossover. Personally, I thought the suggestion kind of odd when I first read it. Or is "acoustic radiation pattern" not the same as dispersion?

http://www.enjoythemusic.com/news/0108/outlaw_lcr.jpgO (http://www.outlawaudio.com/)utlaw Audio (http://www.outlawaudio.com/), an Internet-only direct-to-consumer electronics brand, has introduced the Outlaw LCR loudspeaker ($649 each for black finish, or $699 each for cherry veneer). This flexible home loudspeaker is the first to include the company's exclusive MCO (Main/Center Optimization) selectable crossover technology. This allows the speaker's acoustic radiation pattern to be optimized for use as either a left or right front speaker or as a horizontal center channel speaker simply by flipping the MCO switch. A high-frequency adjustment switch allows the tweeter output to be boosted or lowered by 2dB to compensate for acoustically 'live' or 'dead' rooms. Finally, each loudspeaker employs a proprietary three-position Boundary Compensation switch to tailor output for placement near walls, corners, or in open air. Designed and hand-built in the USA to audiophile-grade performance standards, the Outlaw LCR features the same long-throw 5.25-inch SEAS woofers and custom designed 1-inch ferrofluid-cooled soft-dome tweeter. Audiophile-grade crossover components, including 100% film capacitors, high-end drivers and a low resonance MDF cabinet. Each loudspeaker is tested and matched to within 0.5dB of Outlaw's reference standard. This ensures that speakers, even if bought at different times, will be optimally matched to one another for excellent performance. Each Outlaw LCR employs two pairs of sturdy five-way binding posts, and is fully compatible with bi-wire or bi-amplification applications. Frequency response is from 75Hz to 22kHz (+/-3dB), sensitivity is 90dB/W/m and it presents a 4 Ohms load.

grumpy
01-04-2008, 01:07 PM
... probably a D'Appolito-like crossover for vertical use and a different
topology for horizontal. Modifying the FR and phase of the two mid/bass
drivers can certainly change how they interact/interfere, and therefore the
radiation pattern. ... and likely less to do with the dome tweeter itself, but I'd
be interested to hear otherwise. -grumpy