Raising the While Flag on 604 Project

[Seadweller]

Hi gang,

Well, as many of you know, I’ve been working on a Great Plains 604 based project for over 2 years now. My progress slowed considerably 6 months ago, and over the last 6-8 weeks, it has stalled completely.

I’ve come to realize that life is just too busy now to finalize this project, so I’m getting ready to raise the white flag. I guess something like this is better done during retirement! I already sold my tube amplifier, so I now have two magnificent loudspeakers sitting quietly in my living room.

I’m embarrassed to admit how much I have invested in them. The cabinets were made by a craftsman that specializes in custom cabinetry for multi-million dollar homes. Most of his handiwork is in excess of $100K. I used a proven cabinet design, with input from a variety of kind and generous individuals. I had actually dreamed of turning this project into a very small, boutique commercial venture, custom building speakers for clients. The cabinet construction was heavily documented with photo’s, and I can obtain the drawings, which were done by hand, yet look like they were generated by a CAD program. The drawings themselves are magnificent, and were done so the system could be mass-produced if desired. I even used commercial parts, such as gold binding posts, polypropylene inserts for the ports, etc.

I have two sets of XO’s, the original Great Plains set, and a custom set that was built by a wonderful gentleman out of Chicago, who lives and breathes these types of drivers. They are built on Plexiglass boards, hand wired and soldered point-to-point. They're magnificent! He is certainly on the brink of a breakthrough with this XO.

I guess I’m looking for some advice on selling the speakers. I realize that is a very special speaker system, so an ad in my local newspaper won’t cut it. I don’t even know how to value them. Of course to me, they’re worth a million!

Any input or advice would be most appreciated!

Thanks!

[Panomaniac]

Photos, lots of photos, please

[valhallax]

all i can say is...see it through. sounds as if your almost there! if you go to any of the boutique shops, your pair will blows theirs away! you can do this. sell them?! no way, hook 'em up and play your favorite music through them

[Seadweller]

all i can say is...see it through. sounds as if your almost there!

Well, the reason I pursued this project to begin with, is because I went down the "high end" path many years ago, and could never find a system that recreated the magic that my Model 19's provided. I went through numerous systems, from Thiel, to Martin Logan, to Magnepan, to Von Schweikert, to......After visiting CES two years ago, I realized that none of the consumer products appealed to me, with the exception of systems like the Edgarhorn, which are hideously expensive.

Anway, I've been fighting with extreme midrange energy and weak bass output through the entire project, and I just don't have time to take measurements, and do what's necessary to finish this out. Right now it's a matter of tweaking the XO's, but I don't know how to do it. The gentleman that has been making the XO's for me has already built 3 pair, which is well beyond any expectations I had.

I've tried Stehpaen's 4th order, the Great Plains stock version, Jeff Markwart's 3rd order, and 3 custom XO's to no avail. While it seems as if I'm close, I'm in the same position I was the day I put the drivers in the cabinets.

I'm a little disillusioned at this point, and the excitement is slowly waning...

[Seadweller]

Photos, lots of photos, please

Here's a sampling...Hope it works...

[Panomaniac]

Thanks, great photos. Very pretty.

I have to say, the box looks too small to me. Maybe that's why you're struggling with not enough bass - too much mid?

Can you post the inside dimensions? There are a number of skilled box guys here, perhaps they can help. And the port size and length is important.

edit:
Hmmm.. looking again a doing a rough estimate, the boxes are not small. Maybe 42Hx24Wx21D.

[Seadweller]

And a few more...The press-fit grills are a work of art...

[GM]

Anway, I've been fighting with extreme midrange energy and weak bass output through the entire project..........

Hmm, something doesn't 'ring true' as the 'spread' through the XO BW should solve the 'hot' mids, but for sure the larger HF horn that allows a nominally 1 kHz XO I'm a 'broken record' about will solve it. Ditto woofer diaphragm treatment, but this typically requires significant experimentation with the real possibility of ruining some before getting it right.

As for weak bass, these drivers either must have a huge cab tuned to blend as well as practical to the room and/or a very high output impedance source combined with good room boundary loading, so with such an acoustically small cab you apparently don't have the latter and I assume the Fs tuning required.

GM

[Panomaniac]

What I ended up with on the Mantaray orn 604s I have was nominally ~1600Hz, 3rd order crossover with a spread. I'll see if I can find my notes.

I found that the mantaray horn just would not play down lower and stay clean.

[Altec Best]

This is one story I don't like to read.I guess it's the part where you may Give Up.You seem to be so close.The 604 should be in a box 9cu. ft/620a for best bass performance I have a pair of 612C's that are 6.8 cu. while the bass is good the extra 2.2 cu. ft will produce much better bass response.

If anything felt like a million bucks to me I would keep them !!! And I would be looking for a new Amp

I'll be building a set of 620/modds soon as soon as this 3 ft. of snow melts I wish you the best and hope you can stick with it especially after putting 2 years into it.