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inrank 25th January 2012 05:02 PM

Fountek FE85 Bipole
I am about to order two pairs of the Fountek FE85 for a small bipole speaker.
Would I have any advantage ordering double and have two firing forward, two firing back on each speaker. (as they are under 10Euro each)
I know about lobing, but some people have used similar sized drivers together (like the Jordan and Bandor ones) without any filters between them.

It would be similar to these (a previous design I have done with Bandor 50mm drivers)
Bandor Tower 1 by hoopsontoast, on Flickr

But with two on the back, and no Volt Radial Subwoofer.

Thanks, Rob

inrank 26th January 2012 07:52 AM

My previous ones i designed a few years ago, worked really well in the near-field. (placed a good bit further out into the room)

inrank 26th January 2012 12:36 PM

Oh well, went ahead with just the 4, so a normal bi-pole it will be!

BHD 26th January 2012 12:55 PM

Those speakers look great, by the way.

hm 26th January 2012 11:07 PM

i made a few bipol double horns, no sub, down 34 Hz,
for 3"-8" driver, view my HP.

inrank 27th January 2012 07:43 AM


Originally Posted by BHD (
Those speakers look great, by the way.

Thanks I have made a quick CAD Model, which is what I am planning, except that the drivers are back ordered a month, every supplier does not have any stock.

Very simple, with the two FE85's mounted magnet to magnet, in a small sealed box with extra wide baffles. Its around 960mm x 600mm x 130mm.
Its roughly the Golden Ratio in dimensions (except depth), and with the driver placement.

Aiming for something a little like electrostatic speakers, but to be used in the near-field (around 1.5m from the listener, and around 1m from the rear walls.)

Charcoal 27th January 2012 07:50 AM

as for me nice Idea, but I wood add some 8 inch midbass in bipole also and cut FR at 300-500Hz. But it will be bigger dimensions of cause. If tu use just FR, why to use sealed box and not TL(better excusrsion. more bass)?

inrank 27th January 2012 07:57 AM

I had thought about it, as the fs-125 being not too low the line length would not be too long, I get confused with the maths of working out the TL path. I understand that I would would want a 2.7m line (or 675mm if 1/4 wave) going from an area at the top roughly equal to the SD (1>1.2*sd) which is 27cm2 and a ratio of the line from 10>1 for a sealed Transmission line.
I do have a copy of the MJK Alignment Table paper, but I just get confused.

Charcoal 27th January 2012 12:00 PM

hornresp is isi way to simulate also

inrank 29th January 2012 04:33 PM

I am going to go with the FE87, side by side they look the same cone, just one with the shielded magnet.
And the FE87 has a higher Qts, which gives me 100Hz@-3db in a sealed 4Litre box with two of them.
And mainly as everywhere in Europe is out of stock atm with the FE85, but lots of Fe87 :)

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