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Discussion Starter · #1 ·
Just looking for anything in general. What amps, processing, EQ, room placement, etc... if using a passive OB how did you design it? If using dipole subs what slope and x-over point are you using and what driver of course?

I would just like to start a small OB/dipole discussion if anyone here has used or done anything similar or related.
 

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I'm using AA poly mids, soon some Whispers to run in place of some Vifa DN26s and soon Dayton DVC 8s on 3'x1' mdf panels. They are about 3 feet from the back wall and about five feet from the side walls.

I run a DCX2496 into a Marantz 4200 6.1 receiver.

Not fancy at all, but they're my first OBs. My apartment has THIN walls, so I don't crank it either.

And yourself?
 

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Discussion Starter · #3 ·
As of rite now nothing. I need to start/finish my dayton BIBs, then i'm contemplating purchasing some hawthorne audio coax's. I've got a pair of AA poly's + BG Neo 3s i could try out OB. I guess i could just buy a cheap 4 ohm passive x-over, as i don't have any form of processing.

How did you come about your choice of speakers you selected?
 

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Good reference: Quarter Wavelength Loudspeaker Design

Scroll down to open baffle theory. In addition, look in projects.

Currently I have one open baffle project (mostly completed), which is actually an open baffle line array setup. Baffle is 2 feet wide by 7 feet high. Using 12 6 inch drivers per side, QTS of 1.1 and FS of 40hz. 24 3/4 cheap mylar tweeters per side...

Sounds great. Sound stage is great, but higher frequencies are steered to the sides because I don't have another set of tweeters facing the rear. Huge depth. They are about 1 meter from the back wall and the sound stage seems beyond that wall. Bass extends well into the 40s with authority off 20 watts of power with minimal EQ.

My other project consisted of 15 inch drivers and compression horns from a Magnovox radio in the 60s. Made a U-baffle setup and with a little EQ they sounded phenomenal in a small room. Incredible staging and strong bass, again with only 20 watts. Birthday present for my GF and she loved them :)

Check out Linkwitz Lab as well Linkwitz Lab - Loudspeaker Design

I will never go to a boxed system again. The bass produced is effortless and completely uncolored. If you pick the right driver parameters, and use multiple drivers for the lower octaves, there is no compromise for bass. In fact, check out MJKs latest project using an 18 inch Goldwood pro driver open baffle. He has achieved response down to the 20s with an open baffle driver!

Jordan JX92S OB with a Goldwood GW-1858 Woofer in an H Frame Project

Hope this gives you some insight. Definitely use rearward facing tweeters (reversed polarity) to match the response of an open back woofer. Feel free to ask me any questions.

Regards,

Serg
 

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Discussion Starter · #5 · (Edited)
Thanks. Those were my first two sources when researching dipole speakers. I really like the double h-frame (i guess that what its called) on the orions. Since then I have mainly used the forums on hawthorneaudio, diyaudio, and audiocircle.

When picking a driver(s) for dipole bass, which factors do you feel is the most important? (qts, fs, efficiency, x-max, others i have overlooked)

I find the experiments with the Eminence Alpha 15s + a full range, with a minimalist passive x-over approach to be interesting and will probably be my first own experiment with OB. The goldwood 18s also caught my eye, but i'd like to see my projects with them.
 

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Thanks. Those were my first two sources when researching dipole speakers. I really like the double h-frame (i guess that what its called) on the orions. Since then I have mainly used the forums on hawthorneaudio, diyaudio, and audiocircle.

When picking a driver(s) for dipole bass, which factors do you feel is the most important? (qts, efficiency, x-max, others i have overlooked)

I find the experiments with the Eminence Alpha 15s + a full range, with a minimalist passive x-over approach to be interesting and will probably be my first own experiment with OB. The goldwood 18s also caught my eye, but i'd like to see my projects with them.
I personally prefer a higher QTS. But to some, a driver with a lower QTS and a lot of Xmax is preferred. Coupled with EQ and a lot of power these setups can have more headroom.

The best way to experiment IMO is find drivers in your home that you have laying around and try them IB. Wood is cheap. Experiment with baffle width, different baffle types, and room placement.

As long as the driver isn't complete crap, I have found that Inexpensive drivers have the most impressive bass (as far as quality, not quantity) just because they generally have such a high QTS and perform well with minimal EQ.

Once you get the hang of it, make sure you have a lot of displacement on tap. On the order of four Alphas or two 18 inch goldwoods. My two 15s fill a small to medium size room well as long as I don't approach live levels. They only have around 2mm of excursion and with most music I have to place my hand on the cone to feel them playing. Once I play music with information below 40hz they slowly start to struggle, but still have some output left at low levels. Very impressive for barely any power and no box!
 

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I am running a pair hivi 3" fullrangers with a bg neo 3 on each side of my pc monitor in a 3/4 complete box with no back on them. I wanted to hear them full range before completing the project a few years ago and i am glad i did, as i left them this way since they do sound quite well. They are hooked up to one of my bsg 6 channel amps i picked up a couple years back with 2 of the channels bridged to a tangband 8 from the logitech z-560 set. I use the foobar2000 program for all of my eq/xo/ta/etc. and it works out quite nice, but i just wish i could run all of my sound through foobar, as when i listen to the speakers on any other program they are just fullrange so i have to keep the volume down.
 

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Discussion Starter · #8 ·
Your running a full range with the BG Neo 3?

How does that work, since the hivi is such a low efficiency speaker with the planar?
 
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