# adding rear tweeter to create omni/bipolar...



## hearingspecialist (Mar 15, 2010)

I was experimenting last night with my MTM towers after reading a post on partsexpress techtalk. The post was talking about omni directional listening and the effects of the 3d image received from said setup.

So, i got to thinking and added a set of soft dome tweeters to the back side of my towers in the exact spot as the fronts but just on the rear. This creates a bipolar high frequency system and all I can say is WOW!!! My top end completely woke up. The more defined stage and image with the dimensional sound is so awesome!!! I sampled all my test and reference discs this morning before work and music is awesome, transformers..., what a difference it made.

I think the key was making sure the polar patterns didn't create phasing issues and aligning them equally was also a major component. I did try to match efficiency and got lucky that a set of new tweeters were just laying around my office. Bipolar setups do make a difference, now what if I could do the mid woofers too.....:nerd:


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## dyohn (Apr 17, 2008)

One trick is to use an L-pad with an ambience tweeter (or wide-band driver) so you can "dial it in" to match your room requirements. Congrats on your successful experiment.


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## Jungle Jack (Jul 28, 2009)

Hello,
Very cool. It is amazing what tweaks and proper setup can do for getting the most out of your Speakers.
I use Martin Logan Electrostatic Speakers that are naturally dipoles and because of this require them to be setup 3 feet minimum from the Back Wall to get the best sound because of this.
Cheers,
JJ


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## Matteo (Jul 12, 2006)

Very cool. So you are liking it with movies and music? Are you only using towers, and not a 5.1 or7.1 system? 
Matteo


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## lsiberian (Mar 24, 2009)

Matteo said:


> Very cool. So you are liking it with movies and music? Are you only using towers, and not a 5.1 or7.1 system?
> Matteo


bi-polar is really a way to overcome the limited sweet spot of stereo. I don't suggest it for surround systems.


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## Matteo (Jul 12, 2006)

That is what I was assuming, but wanted a little more info on it. Very interesting stuff.
Matteo


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## drdoan (Aug 30, 2006)

Great idea. Have fun. Dennis


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## hearingspecialist (Mar 15, 2010)

^^My setup is a 4.2 system with my mains 60" apart and listening spot 11' back. Everything sounds awesome so far. My towers have a MTM with 4" on top and 6.5 on bottom.

I think building a set of TriTrix (partsexpress) with matching drivers on the fronts and back would be sweet. I could almost seperate those enclosures and add a 12" with 12"passive radiator to mimic a set of Definitive Tech's.


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## chadnliz (Feb 12, 2010)

I run VMPS FF3SRE that have a 53in open baffle planar midrange driver that covers from 280hz up to somewhere like 8000hz before ribbon tweets take over and I lve the sound, I also have Innersound Eros MKIII Electrostat hybrids in storage that were great for mains but had a limited sweetspot so I pulled them.
I like di and bipoles for sides but prefer standard speakers for rears in 7.1.5 different people will likely have 3-5 different views on surround speaker implementation.


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## lsiberian (Mar 24, 2009)

hearingspecialist said:


> ^^My setup is a 4.2 system with my mains 60" apart and listening spot 11' back. Everything sounds awesome so far. My towers have a MTM with 4" on top and 6.5 on bottom.
> 
> I think building a set of TriTrix (partsexpress) with matching drivers on the fronts and back would be sweet. I could almost seperate those enclosures and add a 12" with 12"passive radiator to mimic a set of Definitive Tech's.


I'd start with a sealed design. The TriTrix is a TL. Omni-polaring it is a no-no.


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## hearingspecialist (Mar 15, 2010)

Yep, clarification...no TL, sealed for the sets of MTM's and then sealed with passives for the sub.


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