Frugel-Horn XL for Alpair 10.3/10p, Fostex FF165wk, more

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We showed the 1st prototypes of the Frugel-Horn XL for the Alpair 10.3/Alpair 10p* at this summer's VI diyFEST. Subsequently Mark heard them when he stopped by at the end of his recent visit to Canada.


*(will wotk with older A10 but is less optimal)

All-in-all we ar every pleased with the results and it is time to get the plans ready for release.

Unlike the original Frugel-Horn and the Frugel-Horn Mk3 there will be a charge for the planset. We are proposing a minimum $10 donation to the forum in exchange for the plans.

But before that we need a couple or 3 beta builds to help hammer the planset into shape... it is currently just a plan view.

If you are interested -- they need to be built fairly soon -- send me an email.

Attached is a plan with the extents noted, these are a fair bit larger than the FH3, make sure they will fit.

Chris is just finishing up the finish on our prototypes, i willpost pictures as soon as i can.



edit (22-aug-16): How to get detailed plans


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No pressure at all Chris. ;)

It's not a small speaker, but with that said, the overall dimensional increase over FH3 actually isn't vast. To pre-empt some queries, like FH3, they're intended for boundary loading for optimal performance, so you don't need to have it way out into the room. It's essentially an extension of the FH3 alignment & the internal choke primarily serves as a low-pass filter. As Dave notes, the 10.2 & original 10 will work, albeit not quite as well as the design units. Any other drivers will have to wait until after it's gone through beta, so please don't ask at this time; we'll simply quote this sentence. ;) They should be good for a conservative open E double bass (~42Hz).
This will be interesting. Been contemplating the mk3 forever, but worried whether they would play loud enough for me. The XL would play louder and go deeper, right? What other benefits can we expect?

Btw, a fee for the plans is quite fair. You must have spent many hours on this.
Joined 2001
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The XL would play louder and go deeper, right? What other benefits can we expect?

With the new A10s Mark has gone a long ways ro closing the gap to the things the A7.3 did better than the A10.2 -- much of the edge the A7.3 has requiring very good ancilliary gear to realize.

So if you can afford the extra cost (A10 is a bit pricier, and expect to use 2x the materials), and the larger size, the FHxl gives lower bass, greater dynamic potential, and higher efficiency at a small expense in top, DDR and midrange finesse (the last 2 requiring the front end kit to realize).

FHxl is likely a better single driver all-rounder than the FH3 with A7.3. Add a helper woofer all bets are off -- the bi-amped FAST we have with A7.3eN and 2 x SDX7eN is the best speaker we have done yet IMO.

Are there any prospects of flat packs?

Last year I built a pair of FH3s for my daughter in Sydney while on a visit to Oz. I ordered the flat packs from the bloke in Geelong. Knowing the high cost of tools in Australia I bought a bunch of the inexpensive clamps on sale from Harbor Freight and took them along.

18" Ratchet Bar Clamp/Spreader

I was sort of hoping customs would want to inspect my bag.

I suspect Dave will be offering them, assuming they fall within practical postage sizes / weights etc. At present nobody except myself, Dave & Chris have the plans, so I wouldn't anticipate possible flat-packs from other sources for a little while, especially since we'd need to sort out some sort of a royalty arrangement for the forum.
As for material break-out a pair of FHXLs would require 2 5x5 Baltic Birch, or approx 1 1/2 sheets of 4x8s for the cases.

I used 18mm for these guys, as the A10P is definitely capable of deeper and more prodigious LF response than the A7.3.

For veneering, depending on the figuring of selected species, and your concern as to grain matching / alignment, etc, you should just barely be able to squeeze them from a single 4x8, provided you paint out the rear mouth.
Joined 2001
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A7/3eN in a mid-TL, 2 SDX7eN in parallel in sealed cabinet. Wide, shallow cabinet*. 160 Hz 1st order PLLXO.

*(part of the effort was to allow Chris to try out some new (to him) cabinet crafting techniques -- as built they are not for the faint of heart, but the basic design could be considerably simplified for a much easier build)

Unfortunately we have yet to find a new woofer we like as much as the SDX7.