[Duke]

To those who aren't familiar with, the Dream Maker is a fairly high-efficiency, tube-friendly bipolar speaker that I showed at RMAF in 2007 and at the Lone Star Audio Fest earlier this year. It subsequently received a 2008 Golden Ear Award from Robert Greene of The Absolute Sound. He was later asked why he saw fit to give that award, and here is part of his reply:

"They have a really impressive ability to interact with the listening room correctly. (This is a speaker where DSP correction is all but irrelevant for instance--almost nothing happens--and there are few of those around, I assure you).

"I think the wavegide idea is a good one and this seemed to me a particularly convincing instance. The speaker also strikes me as a bargain [$9000 a pair]. In a world where people are paying more than twice its price for minimonitors, here is a speaker with real bottom end extension, full range sound, real scope and dynamics, for a rational price."

Here's the link:

http://groups.yahoo.com/group/regsaudioforum/message/23243

Here's the page from my website with specs and a description of the Dream Makers:

http://www.audiokinesis.com/akspeakers.htm

Here's my thread explaining the theory behind the Dream Maker's design:

http://www.audiocircle.com/index.php?topic=56877.0

This is the speaker that Lynn Olson liked best at RMAF '07.  He didn't come to my room in '08.

So anyway with the present economic slowdown, I'd like to re-invest what I have presently tied up in enclosures and drivers for the Dream Maker.  Therefore, I'm offering the parts in kit form at a couple hundred dollars over my cost (and of course much less than retail cost). 

Here's what the kit would include, for $5,000 plus shipping:

- Two Maple Dream Maker enclosures, some minor work required smoothing the finish along the edges, drilling screw holes, and installing constrained-layer-damping panels.

- Internal acoustic damping panels and instructions on how to apply them.

- Four TAD TL-1102 alnico magnet woofers, which are now "unobtainium".

- Four Beyma CP-385Nd polyester-diaphragm compression drivers.

- Four DDS ENG 1-90 waveguides, hand-grinded so they fit into the cabinets, and so the drivers can be mounted, along with foam for making the mounting gasket.  Damping material applied to the waveguides so they don't ring.

- Instructions on how to mount the compression driver to the waveguide so that you get a smooth transition.

- Two input terminal cups, and two tweeter-level resistor terminal cup.

- Four 3" diameter Precision Ports.

- Crossover parts list and schematic.  You can improve on the original by using hotrod crossover parts that were not practical for me to use.  Thie crossover is really the heart and soul of my design.

- Four crossover mounting boards, two for each speaker.

- Two plywood shipping crates for the enclosures; the rest ships in cardboard boxes.  If you live close enough I'll deliver 'em without the crates, and we'll adjust the price accordingly.

I can do some of the work myself, if you would like, for additional fees.

I will ask that you keep the crossover design confidential.  You see, the day may well come when the economy is booming again and a virtual drop-in replacement for the TAD woofer is readily available, in which case I may want to start cranking 'em out without it being easy for someone to copy my design.

Let me know if you have any questions, and thanks for taking a look.

Duke

audiokinesis at yahoo dot com

[Duke]

The kit sale has been discontinued, as I'm running out of TAD woofers.

Duke

[jimdgoulding]

The kit sale has been discontinued, as I'm running out of TAD woofers.

Duke

Duke-  I'm as impressed with the brands you carry at home as much as I am with what I believe your speaks can do.  Salude!  Has Lone Star happened in '09 already? 

[Brad]

Lone Star Audio Fest is in June this year (19-20-21)

[ttan98]

Duke,

2 questions please,

1. Are the drivers wired in parallel or series, ie the 2 woofers and the 2 tweeters?
2. Are the woofers and also the tweeters wired so that they are out of OR in phase?

Hope you can ans these questions. I am thinking of building a bipole speakers.

Thanks.

[Duke]

Jim -  Sorry I didn't get back to you on that; it's in June like Brad said, and I won't be there this year.

ttan - I use series connection for both woofers and both tweeters, as this gives an OTL-friendly 16-ohm load.
The woofers must be in-phase (both pushing outward and pulling inward simultaneously); the rear-facing tweeter can be out of phase with the front one if you wish.   

The reason I connect the rear-facing tweeter in-phase is because that way the frequency response in the crossover region is smoothest, and thus the frequency response of the reverberant energy is smoothest.  Now there is an argument for wiring up one speaker with the rear-facing tweeter out-of-phase, and the other in-phase.  This would serve to further de-correlate the reverberant field, which in theory is desirable.  I did one uncontrolled listening test and concluded that the difference was not obvious, but it took so long to make the changeover that I couldn't conduct a meaningful a-b test.  The right way to do the test would be to bring the rear tweeter's wires out the port so that you could quickly switch connections, and to use a "blind" listener to evaluate it, and I never did that.

There is some gross misinformation in circulation regarding series connection of woofers, unfortunately originating from JBL so it is given a lot of credibility.  The misinformation says that series connection will ruin the amplifier damping factor.  I have taken measurements which prove this is not true; the Qes is unchanged by series vs parallel connection. 

I have been told by an amplifier manufacturer that even solid state amps often sound best with a 16-ohm load, but of course only as long as the amp isn't pushed into clipping.  Note that a voltage-source-approximating amplifier will put out about 4 times as much power into a 4-ohm load as into a 16-ohm load.  Tradeoffs, always tradeoffs. 

[jimdgoulding]

Duke-  Gonna talk to the gang at The Houston Audio Society and see we what we can do to lure Lone Star to Houston next year.  You come to that one, ya hear!  I will personally beat the drum to get a big regional turn out (with the help of friends of mine) and turn you on to some Cabo style "messican" cuisine and a little jazz haunt that's cool.

[arthurs]

Bummer you won't make Lone Star this year Duke.  You can ignore my previous e-mail of course.  Standing offer on hosting if you should be this way in the future.