Fountek FR88-EX enclosure

[Mayuri]

Hello everyone!

I am thinking of building small computer speakers with these elements. I already have a Peerless SLS 10" subwoofer in a 60l closed enclosure, so they only need to go as low as about 150 Hz. The thing is, I can't decide on an enclosure.

I've been considering a sealed enclosure at the moment, but I'm afraid it might not go low enough to fit nicely with the sub. A reflex enclosure might also go, but I just can't decide.

Help and expertice will be much appreciated!

[sharpi31]

I have a pair of Foutek FR88-EX drivers in small bass reflex cabinets designed for Fostex 3" drivers. They're at work so I can't take measurements of the cabinet and port, but they are one of the small BR cabinets shown at the bottom of these PDFs (although I'm sure my port diameter is closer to 30mm - I think all three of these have 40mm ports):

http://www.fostexinternational.com/d...3e_enclrev.pdf

http://www.fostexinternational.com/d...e/87e_encl.pdf

http://www.fostexinternational.com/d...e/85k_encl.pdf

They speakers sound brilliant - much warmer and fuller than when I had FE87E. Visaton or Tang Band drivers in them. I'd have no reservation going for a similarly sized BR. I'll happily measure the port and internal dimensions so you know what volume and port tuning I'm enjoying. Then you can simply use WinISD to emulate the parameters with your own cabinet design (or just copy them).

Tried lots of small drivers and cabinets - the Fouteks in these boxes are by far the best of the bunch. Proceed with confidence!

[norman bates]

Looking at the fountek fr88-ex graphs and zaphs comments, it seems to be excellent.
Harmonic distortion looks low for a 3", not fmd, but hd.

"The 830986 is still one of my Favorite small midranges, but the FR88-EX out performed it in just about every way.... I have a pair already, and tested them in .75 liters sealed crossed at 200hz at the lowest running on a Soundstream MC300 for 75 watts rms and they got loud enough for me as loud as the dayton and peerless units I test sometime back and this is my house. (from here I come)
Zaph's Test of the Fountek FR88-EX 3" wide-bander - DIYMA.com

and from zaph "This is without a doubt the highest performing 3" I've come across, at least on a few fronts. The motor is an underhung neodymium design and the cone is thin (and fragile) formed aluminum. The only negative is a slightly ragged top end that may take some filter work if used full range, but I'd generally recommend a cheap and small neo tweeter placed close and crossed over high. There's a lot on the positive side, like high sensitivity, a clean low end and smooth midrange response. The frame is cast with ventilation under the spider, but users will have to pay close attention to airflow behind the cone - It's even more important to chamfer the inside baffle opening and in this case likely use a thinner baffle material as well. "
Zaph|Audio

I've been scared to use an aluminum cone (resonances)..........

It (fr88ex) seems to be a cheaper version of the h-audio trinity driver (titanium and magnesium cone, better motor and frame), but the fr88ex runs $27 each while the trinity is near $115 each.

"The $50/pair Fountek FR88 and $60/pair Tang Band W3 bamboo's are easily as good in both quality and sound departments as the big dollar drivers. The thing is, each of these drivers has a different overall sound, so I would recommend starting with the material that suits you best. Paper/ aluminum / mixed alloy metals / poly, etc all have some different sonic qualities because of the mass and stiffness of the cones.
I prefer paper and paper hybrid cones myself and because of that I ws naturally drawn more to the warmer sound of the Tang Band W3 bamboo's, the HAT L4's and surprisingly, even these Trinity's with the softer metal alloy. "
H-Audio TRINITY review - DIYMA.com

So, for value, the fr88ex and tb 3" bamboo, or spring for the trinity (too rich for my blood).


I did see a review saying the alpair 5 ($30 each) was similar to the fr88ex. (alpair prefered ?)
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The alpair seems a little better but the fr88ex has better highest end crisp, but both are high resolution devices.

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I'm thinking about getting a pair to make a nearfield demonstrator.

Norman

[Mayuri]

Originally Posted by sharpi31

I have a pair of Foutek FR88-EX drivers in small bass reflex cabinets designed for Fostex 3" drivers. They're at work so I can't take measurements of the cabinet and port, but they are one of the small BR cabinets shown at the bottom of these PDFs (although I'm sure my port diameter is closer to 30mm - I think all three of these have 40mm ports):

http://www.fostexinternational.com/d...3e_enclrev.pdf

http://www.fostexinternational.com/d...e/87e_encl.pdf

http://www.fostexinternational.com/d...e/85k_encl.pdf

They speakers sound brilliant - much warmer and fuller than when I had FE87E. Visaton or Tang Band drivers in them. I'd have no reservation going for a similarly sized BR. I'll happily measure the port and internal dimensions so you know what volume and port tuning I'm enjoying. Then you can simply use WinISD to emulate the parameters with your own cabinet design (or just copy them).

Tried lots of small drivers and cabinets - the Fouteks in these boxes are by far the best of the bunch. Proceed with confidence!

Thanks for tips! I'd be grateful if you measured the boxes, it'd be nice to get on building decent speakers for my computer at last.

[borispm]

The manufacturer recommended a 3L BR tuned at 70Hz, and f3 is 70Hz. I haven't tried that, but it looks great on the sim.

[Uncle Meat]

Last night I finished my FR88-EX Satellites. The cabinets are 1,5l net CB, built with 12mm MDF.

They run with a Labtec Pulse 485 , 4" BP Sub that rolls off around 150Hz.

As proposed by Spectrumaudio.de , I use a notch filter ( 0,33mH, 8,2yF, 4,7Ohm ).

What can I say? Almost perfect

[Mayuri]

Originally Posted by borispm

The manufacturer recommended a 3L BR tuned at 70Hz, and f3 is 70Hz. I haven't tried that, but it looks great on the sim.

This might go well with my sub, and WinISD also confirmed this is almost the optimum for a BR enclosure. The satellites will be placed close to the wall, so should I modify the design somehow to compensate for that?

[sharpi31]

Measured my cabinets: Internal volume 4.02L (minus stuffing, port and driver displacement). Port is 58mm long, 30mm wide. Models like this on WinISD:

[sharpi31]

Did another quick sim on WinISD. Revised cabinet volume down a bit to allow for stuffing and port etc. (assumed 3.8L). Changing port resonance to 70Hz gave the following plot (green).

Rolled up some A4 paper to extend the port length to 9cm (to make port close to 70Hz). Lost some of that 100Hz weight but better top to bottom. Tracks the bassline in Burial's 'Etched Headplate' more evenly, but with less bass warmth.

[Bob Brines]

Just a general comment: When the FR curve makes a sharp bump just before cut-off, it is a sure sign that your cabinet is too small.

Bob