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strider75 21st January 2011 06:50 PM

Twin pipe resonant air couplers
More specifically the Windermere (single and twin driver versions)

and the Aln

My 20 month old son "modified" the dome on one of the FE127e in my set of Fonkens to a degree that looks to be beyond hope. Looking for the next project the Windermere caught my eye. The fact that it digs a bit deeper then the Fonkens intrigues me but at the same time the comment about the trade off being "a loss of midrange finesse" has me concerned. Any thoughts on how they'd sound? What are the advantages of the different orientations of the second driver in the twin driver version? From what I've read about the EL70 looks to be a pretty strong driver.

The Aln looks pretty similar, I guess they'd be more efficient and dig lower still. Any thoughts on them?


planet10 21st January 2011 07:08 PM

Scott's designs, i'll ping him....

These are based on the Japanese Nessie's. No one has reported back on a build of either of these yet,

Narrative in threads on Calhoun, Lotus^2, & Coniston^2 will give you some ideas on effects of driver "orientation". Including some comments on filtering 1 driver to get a 1.5 way.

EL70s can produce bass that is hard to conceive given their size. With sufficient break-in EL70 (500+ hrs, at least the EL70eN i have experience with), the difference in midrange finese vis-s-vis FE127 decreases to the point that differences are mostly in the presentation, FE127 being more forward. The stock EL70 also has an advantage of no 7 kHz peak vrs stock FE127.

It would not surprise me if Twin EL70s go lower than A12. A12 has more downward dynamic range, and requires top notch ancillary kit to get the most out of them (althou the same could be said of anything, some stuff does not put a spot-light on the shortfalls of lesser kit)

And if it was a contest involving typically rock material, i'd give the edge to the EL70.


Scottmoose 21st January 2011 09:59 PM

Nessie style boxes are always a bit of a leftfield option due to their unusal looks. Personally, I quite like them from an aesthetic standpoint, and they do allow a very low tuning with decent gain for a given driver size. The very long vent (which is what the 2nd pipe effectively is) does need some damping to kill its harmonic structure.

ra7 21st January 2011 11:17 PM

I've read somewhere you can insert a safety pin through the dust cap, get it back out and drag the cap out that way. Don't know if its okay to be poking holes in the dust cap though... especially in a full range driver that relies on it for performance.

strider75 21st January 2011 11:33 PM


Originally Posted by Scottmoose (
Nessie style boxes are always a bit of a leftfield option due to their unusal looks. Personally, I quite like them from an aesthetic standpoint, and they do allow a very low tuning with decent gain for a given driver size. The very long vent (which is what the 2nd pipe effectively is) does need some damping to kill its harmonic structure.

I very much like the look of them, almost as much as a double mouthed horn.

What size room does the Windermere^2 like? My listening space is a portion of an open basement with a low ceiling, maybe 7.5 feet high. The footprint is defined by 14' of the front wall and 16' along the side of the house, parallel to the basement steps. The entire basement is 20' x 32'.

planet10 22nd January 2011 01:02 AM

Dust cap fix split out to here


leeoh 24th May 2011 10:48 AM

Dave. You may remember me emailing you several months ago, about replacing my then current enclosures which had in each two CSS EL70 drivers, one facing to the rear and one to the front. The rationale of the design was that the rear speaker was slightly behind in sending information to the listener's ears, so giving more of a concert hall ambience. I didn't find that it worked for me and although I liked the sound, found that it fell short of my expectations. Around the same time I saw a design by Scottmoose of twin piped enclosures which promised an even deeper bass and also a rather unusual appearance ("Ugly" I won't even suggest) which appealed to me. They also used the same CSS EL70 drivers which I was using in my then current enclosures. I told you that I would build them and take photos of their progress. i took the photos but have not been able to transfer them to my computer to send. All the small children around here have grown up and left home, so i have no one to help me.
I decided to give them a try, but as good quality ply here (Australia) costs almost $200 a 2.4m X 1.2m a sheet, I opted for 12mm thick particle board, glued into a single sheet which ends up as 24mm thick. These sheets here are about $19 for a single 2.4m X 1.2m sheet (Bunnings) and as I needed four of them, total cost was about $76 plus some offcuts already in my workshop, plus $20 for a liter of white PVA glue.
If I had decided to use the ply alternative but didn't like them when completed, it would have been difficult indeed to throw them into the rubbish. $400 of good ply? i would have felt ill for a week. I don't care near as much for particle board.
So, particle board it was , despite plenty of advice that the enclosures would not sound as good as ply enclosures. I sincerely believe that must be true, but as it is not remotely possible that I will ever hear two identical enclosures side by side in my home, (except for the material used to build them), I would never be able to appreciate the difference. Would I? Dave gave approval but with reservations which I accepted.
To cut to the chase- I have completed the enclosures and have been listening to them for a week. I really, really like them. Bass is definitely deeper than the same drivers in their previous homes and the rest of the sound is very enjoyable. Great clarity right thro' the range and very musical. The sound seems very accurate (lifelike) to me, but then, what is lifelike? Most of the music we hear has been interfered with, one way or another.
If the cost of ply is daunting to anyone, then give the cheaper, double 12mm (half inch) particle board a try. I would be very surprised indeed if you were disappointed with the result. It is difficult (impossible?) to get a good finish on particle board. i cover all exposed edges with solid timber which helps, and spray white paint over it all when construction is finished. Not a fabulous result, but from where I sit about two or so meters away from them, I don't care all that much . i just enjoy the sound. The other influence in the house isn't too critical either, but she is, thankfully, quite forgiving of most of my peculiararities. After many years of my producing quite a lot of antique style furniture for our use, I think that is only fair.
I am sure that I will get some rubbishing from Dave and Scott (and others) for my use of particle board, but better to accept, I believe, a slightly lower level of reproduction excellence than to not have anything at all because of cost considerations.
I have a set of G Changs beside the Windermeres and although I like the G Changs, (also double 12mm particle board) the Windermeres, to my ears are far more enjoyable to listen to. In another part of the house and with another amp and CD player, I have a set of Jordans, but I use the Windermeres in preference to them.
My only reservation is that the high end of wind instruments and male and female voice can be harsh. Possibly a feature of the speakers or maybe the amp, but I have the same problem with either of two tube amps and a solid state.
Now if Mark will only stop making yet more drivers to tempt us and Scott would spend more time enjoying that Yorkshire delicacy - Yorkshire pudding and gravy and forget designing more enclosures, i could be happy. I think. But as that maligned character, Oscar Wilde is supposed to have said "I can resist anything but temptation". R.

zman01 24th May 2011 12:47 PM


Thanks for sharing your experience. The uncommon aesthetic made me curious too (I had looked up the Nessie for Alp 12), but could find hardly anything on listening impressions. You seem to be liking them a lot! And hey it's big, but not as big as most BIBs or some of the double mouth horns. :) Looks like a straightforward build too.

Post some pics when you can.


planet10 24th May 2011 05:19 PM

Thanx Robert.

We have been doing a few particle board builds and it is refreshing to hear how they compare to MDF. Your 2 ply particle board "plywood" should be rather decent. Not up to plywood but it is hard to comprehend the prices you are being asked in Oz.


Scottmoose 24th May 2011 07:12 PM

Why rubbishing? You use what you can & ~an inch of laminated particle board should do the job OK.

Glad you like the boxes.

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