Ouch!!

[Thatch_Ear]

My speaker project that was so easy on paper had so few cuts to make has resulted in at least a tank full of gas, 5 hours on my feet in stores, AFTER all the reasearch I did in stores to figure out how to get what I wanted. I spent $47.70 ea on drivers and at least $300 dollars on other supplies, at least 20 hours of work and I managed to get 4 pieces of MDF together forming the sides top and bottom of one box. I have made 8 router cuts and still have 4 left. Braided wire, drilled holes, clamped, bolted, ratcheted, glued and then my cat pissed on it!!!
I feel like people have been beating on me with sticks and I am too tired to go get beer. There is no way to even try and get finished in time for the DIY Speaker event that I thought I had plenty of time for because it would be so easy.
God I love this stuff! Janurary Bottlehead meet in Austin here I come!:D

[Rob]

Thatch,

I can relate to your sense of weariness. In the past ~6 weeks I have spent a small fortune on drivers, MDF, grille cloth, and other stuff. I received a second batch of woofers via UPS today because the first ones I ordered from PE weren't good enough (my fault, I tried to be too cheap). I have spent two weeks fabricating a pair of fairly complicated, experimental prototype cabinets, and only this evening got the woofers installed in one and did some sweep tests. It isn't working quite like I want, so as expected I now have tweaking to do to dial in the design.

I'm glad I'm not trying to meet a competiton deadline anytime soon like you were. I have all the time I need to fully develop this model before I show it. Without saying much just now, it is to be a very efficient full range speaker specifically targeted at low power SET amp use.

Good luck on your project, and don't worry too much about what the cat apparently thinks of it. :)

Rob

[Thatch_Ear]

Well I got speaker #1 finished and #2 is just waiting on some glue to dry and the last touches to get it up and running.
I rate this as a 95%er. The speaker sounds great, has better bass than I thought I would get out of a 45 FS and let me tell you, the Heil AMT-1 is a knockout.
I sat and recovered to a few CDs and the thing truly outdid my Shahinian Obelisk that was on the other channel. Not an easy thing to do which makes this so much better.
The Eminence Beta 12 LT is rated at 99db and the Heil is, I heard 97db, but the Heil almost (but not quite) needs an L-pad. I love the bi-polar effect of the Heil too. No Sweet spot needed, thankyou.
Ella, Rock and Jazz so far. When I get the other finished I will move into classical and movies.
More to follow.
Julia is in NYC with camera, so pics in a week or so.

[Rob]

Thatch,

Glad your cabinets are turning out to your expectations. I'd like to see and hear the Heil some time.

I think I've found the solution to my bass issue and am doing finishing work now on the two cabinets before I stuff them and install drivers. I should be doing listening tests within a week. I don't want to have to disassemble them to do the finishing so I'm going on the assumption that my design will be close enough to correct that I'll be able to leave these be as a demo pair, minor tweaking assumed. My cabinets each have some 18 separate pieces of 3/4" MDF and consist of many complicated cuts into trapezoidal shapes with the cut angle not 90 degrees to the surface. Very time consuming to fabricate, but essential for synergistically merging both the art and the engineering science of the unique design.

Rob

[Thatch_Ear]

And you are going to sell these for a mere $100 C/pr ? Well I guess I can handle the customs on that. So your working for about 5 cents an hour? Oh yea, your a professor. Big smile and chuckle! :D
Oh yea, saw a bunch of full range 4" sheilded drivers for $5.50 ea. Made for TV I think. Flats are 20 drivers, 2 flats left.

[Rob]

Thatch,

Make that 20 pieces of MDF, not counting the hardwood bracing, or the grille assemblies, two per cabinet.

I don't think I'll be selling these, maybe just trade them in pairs for real estate. :)

Are you getting some of those 4" drivers?

I just bought some 10" Seleniums (10PW3) for another design idea I'm also working on. Those Seleniums are nice drivers!

Rob

[Thatch_Ear]

I just saw the 4"ers at the local (40 mile round trip) closeout dealer. They are not white coned but are hefty full rangers and for $5.50 cheap. I could make a run up there and pick up a couple to play with if you think it might do ya good.
Other than that I thought they would be great in a Di-Pole for a center channel if one wasn't DIY Gods like us.
Most would think you nuts to do that many angled cuts, but since I might spend 200 hours or more on a sculpture I can recognise your artistry.
My offer on the $100 C/pr was purely a joke, but if you are so inclined.......................................... .................................................. .................................:dunno:

[Rob]

Thatch,

I wouldn't mind playing with those 4" drivers, but I'd prefer not to get excited about a driver that I cannot buy in large quantities if I decide it is the cat's meow for one of my designs.....so I'll pass, but thank you very much.

As an artform I see real similarities between a speaker that has been shaped as a piece of artistic sculpture, and a true sculpture. However the speaker also needs to function, making it a multi-diciplinary challenge because the form of art, and the form of technology have to co-exist in a harmonious way within the piece. This is not to say that there is anything easy about creating traditional sculpture. Your 200 hours in a sculpture is not unlike the time I will spend on a design prototype, although I probably average more, depending on the complexity of the project.

A rectangular box is the most used enclosure for a loudspeaker, it is the easiest to make and it is perhaps the worst shape one could employ from a purely engineering sense. It is a widely accepted practical compromise. With my multi angle cuts, and odd shaped panels I am practising and thinking outside the box. :)

I sure have seen some lovely sculpture in the way of DIY speakers from various highly talented and creative builders around the world, thanx to the internet, especially I think in rear-loaded horns.

Creating technical excellence in function, while forming that into art is the challenge I now embrace as I swap hats. I used to spend so much time changing hats that I never got any work done. I now have just one custom made eight sided programmable hat that rotates under BCD addressed stepper motor control. Now I can change hats in just tens of milliseconds. The only problem with this hat is that unlike separate hats, if you get it all hot and sweaty, changing it doesn't help. :( I'm finally getting some of my best and most creative work done now! :)

Rob

[Rob]

Thatch,

I see that the 12" driver you chose is somewhat unusual in that it has a wizzer cone. Were you aware of a shortcoming in the mid range, the low end of the Heils response curve that begged you try this, or have you done this before?

I do hope you will share pictures of your project here. I plan to once mine are successfully completed.

Rob

[Thatch_Ear]

Got the second one finished and have even played a bit with fill densities. The amount of fill does very little to the performance of the bass, which to tell you the truth is a bit lacking.
The wizzer on these speakers are the largest I have ever seen being in that they are basically completely separate speakers from the main cone. I measuered the flat inside and they are just over 2" of cone wrapped around the dust cover and are right at 5" wide.
As far as having problems with the midrange I am not. They are running free with only a single cap on the Heils for a high pass. I was getting some fairly large amounts of coloration but it was from the fact that the Heils were not isolated from the cabinets. As soon as I isolated them it all cleared up.
I did make long hookups for the Heils to give me the ability to move them around on top of the cabinets easily. They phase correctly directly over the magnet of the Eminence.
For recordings with good soundstageing it is a real joy to listen to these things work.
So anyway, no problems with the midrange at all probably due to the fact of the TL going straight back and curving down there are no standing waves to cause that problem.
There a a lot of guys in the Single Driver Forum that have played around with and tried different tweeks on these drivers to eliminate the problem with the mid range but from my listening so far I would hazard a guess that the problem is a box created one.
Even the Hammers exibit this with the modified for the kit version of my driver and there has been a lot of tweeking going on with those as well.
The report from Hurdy Gurdy on the Hammers at Caintucky was that there was a problem with the mids. I believe that the fix has been to modify the crossover to get rid of this problem. It seems that the problem is not from the driver but from the box and using a crossover at all.
The camera is in NYC with my Lady so no pics till next weekend. I will post pics of just the speakers here and of the whole system in gallery.
Subwoofer work beguins today.