# Seeking design idea feedback



## dyohn (Apr 17, 2008)

Hello Shacksters. It's been a while.

I had a minor brain fart today and I'd like some feedback.

I am designing a new set of side surrounds for my living room HT system and had planned a traditional dipole system with dual woofers and dual tweets facing "front and back." I am only able to install a 5.1 system due to room limitations on mounting locations for surround speakers.

But then a thought arose. Why not build two monopole systems into the single dipole enclosure geometry, and use the "front" facing set as the side surrounds and the "rear" facing set as the back surround channels? I would lose the diffusion of a dipole of course, but other than that it seems I could gain the two back surround channels without having to mount a second set of speakers.

Someone tell me why this would not work... or I think I might try it.


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## dyohn (Apr 17, 2008)

OK, well it seems this idea is very similar to the Paradigm ADP surround setup. As they say, there is nothing new under the sun.


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## Theresa (Aug 23, 2010)

Its ok that someone thought of it first, take pride in the fact that you had the same idea as a professional. I think its a good concept and I would go forward with it.


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## dyohn (Apr 17, 2008)

Ha! Thanks Theresa. Yea, I guess when you leave an industry and start doing something for fun rather than for a paycheck you are no longer a professional, eh?  I've checked out the Paradigm product and it is similar, but unlike what I'm thinking of doing.

My proposed design is more a dual monopole driven by separate channels built into a bipole or dipole enclosure geometry rather than a traditional bipole such as the ADP system.

I've got a couple boxes of Exodus Anarchy woofers and a dozen SB Acoustics tweeters in the workshop so I think I will go to the next step and design some Xovers.

Any other feedback from the Shack?


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## Theresa (Aug 23, 2010)

With the Anarchy's you could certainly cross over low with bass management. It sounds like a great solution for those of us who don't have the space for a traditional 7.1 setup.


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## Seaxe (Sep 13, 2008)

dyohn, ultimately only you can address the points you posit. How an individual speaker works in an specific space is the nadir of speaker builders wordwide. That said, build and position the speakers under contemplation, and objectivly measure and report the results. Dipoles are (arguaby) cheaper to build, but may not nescisariley work better in an given space. While I seem to merely list caveats, I urge you to go with your instincts, build what you may, and report your findings.


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## robbo266317 (Sep 22, 2008)

It seems like an interesting aproach, I guess room size will influence the reflected rear sound dramatically. How far back is your rear wall behind the seats?


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## dyohn (Apr 17, 2008)

Thanks for all the comments. I plan to go ahead with this design, and after I'm finished if it ends up working the way I think it will, I'll be happy to share the design with anyone who wants it.


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## Moonfly (Aug 1, 2008)

My setup also only suits a 5.1 setup. I found direct fire speakers simply couldnt compete in any way shape or form with the diffusion from proper di/bi-pole surrounds. I have tried corner mounting and side mounting, pointing them in different directions and ultimately I gave up and settled on di-poles.

Everyones room is different, so my experience may or may not hold any parallels with your own. Once upon a time I had a Bose Lifestyle system, which basically uses direct fire surrounds you can adjust and point in two directions at once, and to be fair that dispersed the surround channel ok (for Bose). 

I reckon the trick will be trying to ensure the rear channels are only really heard from the rear (assuming you mount the speakers on the side walls), so it might be worth trying to consider making the cabinets in such a way as you can adjust the rear fire speakers to help best direct the way it reflects of the rear walls etc, just an idea. No doubt you will be using a Bi-wire terminal to hook up the cables etc, which begs the question, would it be worth considering a terminal that includes jumper bars so the speakers could also be used as a single speaker if desired. Another option might be dual bi-wire terminals to allow phase switching between all the drivers, basically allowing a plethora of options when it comes to exactly how you want to run these speakers. You then have the ability to test all configurations in your own room, and decide which works best/which you prefer.


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## lsiberian (Mar 24, 2009)

Make sure you get the proper delay built in to the back speakers.


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## dyohn (Apr 17, 2008)

Moonfly: Yes, the system I have on paper now will use dual binding posts and the user could wire them as a traditional bi-pole or dipole if they choose. But they will be in separate enclosure spaces and have separate Xover to use them as separate channels.

Lsiberian: As the rear set will be driven by channels 6 and 7 would not the preamp take care of imposing the proper time delays?


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## GranteedEV (Aug 8, 2010)

What if you placed a (smooth) wall- shape in-between the two firing "directions to separate them?

What I mean is something shaped along the lines of the side parts of this dynaudio speaker:

http://www.stereophile.com/images/archivesart/dynevi2.jpg

But with the intention of isolating the two waveforms so they don't introduce instant comb filtering.


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## Moonfly (Aug 1, 2008)

dyohn said:


> Moonfly: Yes, the system I have on paper now will use dual binding posts and the user could wire them as a traditional bi-pole or dipole if they choose. But they will be in separate enclosure spaces and have separate Xover to use them as separate channels.
> 
> Lsiberian: As the rear set will be driven by channels 6 and 7 would not the preamp take care of imposing the proper time delays?


Sure sounds an interesting project, and I personally would have thought the processor will take care of delays etc. Will you be posting the build on here?


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