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-   -   MLTL for dual Jordan Eikona Drivers (https://www.diyaudio.com/forums/full-range/315560-mltl-dual-jordan-eikona-drivers.html)

colmo 1st December 2017 08:32 AM

MLTL for dual Jordan Eikona Drivers
 
Hi everyone I am thinking of building some MLTL cabinets using 2 drivers in each cabinet.
I have seen the post where 3 different height designs are shown with different cut offs for single driver cabinets. I note that for a single driver the CSA is 56 sq. ins and that it should be 112 sq ins for a dual design.
This seems somewhat large as I have seen a commercial design with 2 Eikona drivers which had a smaller CSA but was taller and still had -3db at 29db.
Any suggetions.

IG81 1st December 2017 01:34 PM

AFAIK, doubling the CSA - and Vb by extension - as well as adjusting the vent dimension to keep Fb constant, should indeed be your main concern with regards to LF performance.

That manufacturer's claim for a smaller Vb might be true, but we don't know everything about the design to call BS or not. If true, something else was traded-off to achieve this, likely mid/upper-band sensitivity.

GM 1st December 2017 03:09 PM

Hmm, if it's taller, then the CSA will be smaller for a given net volume [Vb], so maybe the same or larger than the short one.

Regardless, bigger box means more acoustic efficiency below the driver's effective mass corner, so only maybe go smaller if truly corner loaded.

GM

colmo 2nd December 2017 09:45 AM

So should I make it as 2 cabinets side by side or one cabinet with the drivers in a line.
If in a line how shoul I space the drivers

Scottmoose 2nd December 2017 10:02 AM

Always as close together as possible. Usually vertical positioning has fewer problems. We're less suseptible to lobing in the vertical axis than the horizontal. Unless we're lying down. In mid air. Or you're one of the few people with ears on the top & bottom of your head rather than on the sides. :D

GM 2nd December 2017 04:45 PM

Yeah, IME, Altec pushed horizontal driver layouts to the limit with its 9844 studio monitor's 800 Hz/2nd order XO, so not really viable with 'FR' drivers unless vertical space is at a premium and one will be rolled off to create an acoustic baffle step loss filter: https://c1.staticflickr.com/3/2699/4...3b8615fcb2.jpg

GM

colmo 2nd December 2017 07:20 PM

How would putting one driver under the other affect the stuffing.
In the original design that I was looking at the pipe was 30ins long and the cross section 56 sq ins

Colin 2nd December 2017 08:24 PM

Put one driver above the other, as we do with our DCR reflex design. Use the centre point between the drivers as the driver height, unless GM or Scott has better recommendations.

GM 2nd December 2017 09:32 PM

No, you're right.

GM

colmo 3rd December 2017 05:15 PM

Ok understand but as I now have one driver below the other if I stuff the box the same as the original design by Jim Griffin my stuffing goes further down and therefore I will have a lot more stuffing.
Will that cause a problem.
Don't forget the internal height is the same as the original design but I have doubled the csa and 2 drivers go lower down the front.


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