Open Baffle Epiphany!

I was just wondering how much the rear reflections play in the OB sound.
I wonder if having sound absorbing material behind the speaker would help or hinder?
 
Using nothing but absorption panels will kill the back wave. I only have hard surfaces which are good for diffusion but I've read that a combination of both absorption and hard surfaces would be ideal.
 
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No different than many other speakers.
Wideband drivers used in OB/dipole can be closer to the side walls due to the null.
 
Optimally you need 3 ft from all walls.
Not a problem there for me with the sides. Guess I'll have to experiment a little more.
Maybe try a speaker indoors vs. outdoors with zero reflections to really hear the difference.
 
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No different than many other speakers.
Wideband drivers used in OB/dipole can be closer to the side walls due to the null.

If you have a pair of OB's ( ? ) listen to them up next to the side walls and then pulled out from the side walls. When you do that you'll know which sounds best.
 
I never implied that it is okay to put them right up against the side wall.

FWIW I don't really like for them to be less than 5.5' from the front wall.
 
I was just wondering how much the rear reflections play in the OB sound.

Quite a bit IMO.
One demo at RMAF years ago had so much treatment behind the speakers I couldn't tell I was listening to OB/dipole speakers. o_O
Also check out "late ceiling splash" for a similar sound.
 
Not a problem there for me with the sides. Guess I'll have to experiment a little more.
Maybe try a speaker indoors vs. outdoors with zero reflections to really hear the difference.

For the side measurement that's 3 ft to the center of the woofer. Linkwitz recommends 4 ft from the front wall and I've seen other recommendations as much as 6 ft. The important thing is to not crowd them. They need space to perform their magic. If you lack space behind the OB's you can always pull them out into the room and when you're through listening push them back against the wall. I do that all the time and the next pair I build will be on casters.
 
Holy moly a pair of those Voxativ drivers retail for 5 grand.

mkane, how do they sound compared to the other drivers you've used?
 
Some years ago I salvaged these 16" woofers from Sansui speakers left on the curb. They were the only drivers in the cabinets that weren't blown. They were badly faded so I painted the cones with "Wet Look" from PE which not only made them look presentable but also tightened the bass.

I threw together some baffles and low passed them with some passives from PE. But with all the other builds over the years I lost interest in them and they've since been collecting dust in the garage.

This week I brought them into the house, removed the passives and connected them to a Yung SD100 plate amp. They are now providing the lows for a pair of Frugal Horn Mk3's and I was shocked at how seamlessly they integrate. Bass as you might expect is not as deep as the bucket subs but I believe it's more accurate.

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Earlier I had used the high Qts Alpha's as stand alone helper woofers so I knew the idea had merit but I didn't know if the Sansui's would move enough air in free space. Have no idea of Sansui's Qts but they sound excellent in OB's. So much of OB for me has been trial and effort but I don't spend time boring folks with my failures. :)

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For a time I hid OB subs behind two doors in a bookshelf system pulling them out into the room when in use. Did that for a few months and it worked fine with good WAF but was not the most convenient arrangement. It was nice to have a remote control of the woofer's volume as they were powered by the silver JVC AV receiver set on 2 channel output
 

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For a time I hid OB subs behind two doors in a bookshelf system pulling them out into the room when in use. Did that for a few months and it worked fine with good WAF but was not the most convenient arrangement. It was nice to have a remote control of the woofer's volume as they were powered by the silver JVC AV receiver set on 2 channel output
How does Ob sub sound? Do OB move more air?
I couldn’t figure out how to make crossovers and at this point I can’t get any more speakers til I move out.
Why are full range drivers so expensive? Are they hard to make.
 
How does Ob sub sound? Do OB move more air?
I couldn’t figure out how to make crossovers and at this point I can’t get any more speakers til I move out.
Why are full range drivers so expensive? Are they hard to make.

Linkwitz says OB bass is more accurate than boxed bass and I agree. OB's bass requires moving lots of air in open space and looser cones help make that possible. OB bass does not load the room nor is it visceral like boxed subs. Full range drivers are not always more expensive. Look for vintage wide band speakers pulled from open backed consoles and tube organ speakers. 12" wide banders such as Zenith, Magnavox, Conn, Hammond etc can be found on eBay for reasonable prices.
 
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This is a 1957 Magnavox 15" full range that I pulled out of a console. My son's been using it as a guitar speaker power by a Sansui 881, it sounds fantastic. I've done some listening to it in mono with a CD as the source. Really nice bass, mids are a touch dark, top end extends farther than I thought it would. I'd really like to find another one and try them in a stereo setup.
 
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This is a 1957 Magnavox 15" full range that I pulled out of a console. My son's been using it as a guitar speaker power by a Sansui 881, it sounds fantastic. I've done some listening to it in mono with a CD as the source. Really nice bass, mids are a touch dark, top end extends farther than I thought it would. I'd really like to find another one and try them in a stereo setup.

Those big vintage wide band speakers have been coveted on guitar/amp forums for years. That's the reason you see lots of singles for sale on eBay. They're very efficient which means they'll work well with low power tube amps.
 
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