I've seem offset drivers in OBs but not flip flopped FRs and woofers.  Perhaps you are on to a great audio discovery.

Lin has pointed me in another direction now. This Emerald Physics dipole thing has me wound up.
I made a mistake of looking at other EP speakers and saw something else of interest to me. Slide over for the pic, lots of white there!


This also looks doable.
So many options in life.
I'm getting ready to go to St. Louis to shop for wood.

Palomino, the tube is as easy as your nearby Lowe's. Sono tube for concrete footings. I'm thinking epoxy or bondo to cover any flaws, prime and paint.
Today I found a source for my wood slab needs. They had some nice slabs of spalted maple, walnut and several other species that were in the 24" + width range.

Or an open baffle line array...

So many ideas!
Better judgment has settled in, Before I spend $500 for a couple of hunks of really nice lumber, I'm going to experiment on some aspen wood 24X48x.75 panels that they sell at Lowe's for less than $30 a piece.
This way when I won't feel as bad when I screw up. This will also give me the option of moving the 8" driver around to figure out the best configuration.

Where did you end up on the drivers?  Tang Band/Alphas?  If so, how will you cross them or is that TBD?

A bunch of boxes arrived this evening. I've already unpacked everything and wired the speakers to a amp.
The low pass crossover is hooked up to one pair of the alpha's, not caring for what I'm hearing on that side right now.
No discernible bass at this time out of anything, I'm hoping that the baffles will fix that.

I roughed one out tonight. And when I say rough, I mean rough.
It is just a proof of concept at this point.
It does have bass, thank goodness.
I need to make them less deep.
Running the Alpha's full range right now.

VERY cool, Donnie! I'll be most interested to hear what you find is the optimal distance betw the Alphas. Keep us in the loop, will you?

Randy

Pal,

Just curious if you have tired running your Augies full range (by-passing the crossover completely).

My experience with the 15A was similar to yours using a 250hz crossover. When I eliminated the crossover completely the muddiness was gone.

My theory with regard to the muddiness. It's not the driver sounding bad but rather the brain detecting a disconnect between the 15A and the higher frequency driver (a lack of cohesion between the two as far as the brain is concerned).

When I run my 15a's full range the higher frequency driver just seems to float on top of everything from the 15A's. The 15A's present the brain with a cohesive Bass line from about 45hz to well over 1,000hz similar to what a Bass Guitar actually does.

In my case adding the crossover #1: sucked some life out of the music and #2: just seemed to create a transition issue that is a real red flag for the brain. I'm also wondering if the crossover introduces some signal time smearing which adds to the disconnect between low and high frequency drivers?

I used to take the approach: Why isn't this sounding good? More recently I've been taking the approach: Why isn't my brain buying this?

Donnie, even though the equal distances on the sides and above the TB may look nice, it really hurts OB sound.

DBC,

I do not recall it sounding bad when I ran the augies full range.  I can give that a try again just to see if its muddy.  

I can also measure it again to see if it jacks up the high bass/low mids.

DBC,

I tired it and it sounded horrible.  I didn't remember that and I figured it out.  My experiment before was with the augies supporting the monoliths. So with the single driver is unlistenable but with the monoliths it was ok.  I may toss the monos back in and see how I feel about it now that I have some experience with the single driver crossed to the augie.

That might explain why the examples Donnie posted earlier had such a wide spread.  At the time, I wondered why did they make them so deep?

Donnie,
I suppose you could also try offsetting the rear facing one from the front one in the left-right plane, just to get the magnets a field width or more apart.
That would takes some symmetry out of the look but from the front I don't think it would be noticeable.
Anyway, your experimentation will tell much more than my guesses!  LOL.

It's a good feeling to have them both assembled, eh?  I end up rushing something every time.  I'm like a little kid.

Very interested I your thoughts on the alphas running wide open with the tang bands.

I have been using a little eq in audirvana to tame a couple hot spots in the tang bands. Not a lot.  Now getting the best sound ever.

Hi Donnie,

My guess is that your two woofers as configured are really only doing the work of one. Would seem to me that the back wave off the front woofer is effectively Canceled Out by the front wave of the rear woofer. So in effect what your are hearing is the Front wave off the front woofer and the rear wave off the rear woofer (the equivalent of one woofer).

After you have listened for a while, you could test this theory by simply removing the rear panel & woofer. If my theory holds true then you should have about the same bass output with the one Woofer.

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Some thoughts. Based on my experience 3/4" thick baffle material is too unstable, it vibrates too easily. I can imagine that each speaker with twin baffles and twin 15" drivers are vibrating to some degree. If they are vibrating then they are producing sound separate from the drivers. So the baffles themselves become big speaker diaphragms. For proof of concept, 3/4" material is easy to work with but can have very negative effect on the sound quality.

Some of the perceived bass output you are hearing could be from the baffles themselves vibrating in harmony (in phase) with one another. Reversing phase on the rear driver may kill the bass since each baffle would be vibrating out of phase ????

You mention these things will shake the house. I suspect there is quite a bit of vibration being transmitted from the baffles to the floor and out to the side walls by virtue of them sitting directly on the floor. Only way to know for certain would be to sit them on isolation platforms.

I had a period where my floors & walls were vibrating. One would naturally assume this is due to sound waves from the speaker driver traveling through the air, hitting walls and exciting the room surfaces. I finally put the downfiring subs I used at the time on Isolation platforms and this eliminated floor & wall vibrations at high volumes.

Point being: if acoustic energy is being dispersed evenly out into the listening space in the form of sound waves, it's very difficult to make the floor & walls vibrate. On the other hand if you sit 4 Butt-Kickers on the floor (which the Alpha 15's basically are) then it's not too hard to see how the floor and walls would shake.

If your Baffles, Floor & Walls are all vibrating then they are producing sound independent of that coming out of the drivers themselves. Your Decware speakers are stout little suckers with materials and internal bracing specially designed to minimize cabinet ringing (not easy).

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I can tell you if your walls are vibrating the primary cause is not how loud you play. Rather it's the mechanical transfer of vibration from the speakers to your floor and out to the walls. Concrete is worse than conventional wood construction. Scroll down in this link and they discuss concrete floors:

http://www.htguys.com/news/2010/12/5/auralex-subdude-video-review.html

I have a pair of Klipsch RF7 mains that I drive with a 220 watt Peachtree integrated amp. I can easily achieve 100 db continuous with this combination. With subs & mains sitting on proper isolation platforms I have minimal floor & wall vibration. Remove the isolation platforms and the room vibrates causing a reduction in sound quality (mainly loss of clarity & definition).

I wouldn't worry about the way you have the woofers since they make a lot of bass together and very little (none) out of phase.

You think maybe the ground underneath the concrete damps it a wee bit.
I've never seen a driveway or road move like a suspension bridge no matter how windy (see link).

As always people disagree about what happens, why it happens, or if it even matters.

For two new machining centers we just put in at the factory that I work at, we used 160,00 lbs of steel and over 150 trucks of concrete in it's foundation. Maybe that is what I need to do for these speakers.
I'm going to try putting some water pipe foam insulation on the bottoms of the baffles and see what it does. Cheap, direct, and easy.

I'm really enjoying these speakers now.
Their sound is intoxicating.
Probably if I did any kind of testing they would measure way wrong.
But to my ears they sound pretty good, not as good as HR1's, but pretty good in their own way.
I'm going over to Lowe's in a bit to pick up some of those foam snakes that are used to insulate water pipes so I can see if decoupling them from the floor does anything .
Experimentation is fun.

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Have you noticed a change in the bass?  Since you already have the pad and carpet you may not be getting much extra isolation from the foam.  I never had much luck with foam type isolation on my solid wood supports and flooring.

I'm trying to work up the nerve to install the low pass filters into these speakers. Should I waste my time doing it?