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Open Baffle Opinions - I Won't go back to Boxed Speakers Evr Again (maybe....)

https://photos.app.goo.gl/cg64ScibP75b1YVF6

My very last DIY effort after doing the DIY Speaker thing (for myself only) for 35 years (only 5 pairs built in that time). These are my best effort WRT to sound quality. Bass down to 30Hz, sweet treble and midrange to die for.

All Parts Express Drivers. GRS Planar, GRS 12" (Qts = 1.27) Woofers, and Dynavox 5 1/4" midrange/midbass Drivers. All in $600. Still some tweaking to to on the Cabinet and the Crossovers. A simple 1st Order 16uF Sonicraft Capacitor on the Tweeter and a 2nd Order Bandpass on the 3 Dynavox Drivers. The H-Frame Woofers section is powered by an ICE Power Class D (1000W@4 Ω). Two for stereo of course. MiniDSP dialed in for a 250Hz Linkwitz-Riley 4th Order LPF, the Bandpass is 250Hz - 2500Hz, and the Magnetic Planar BG knockoff by GRS takes over at 2500Hz. No L-Pads anywhere !

My question is what is the Phantom Center like ? Mine is not as focused as I’d like it to be. But my God, the soundstage, imaging, front to back depth is amazing. Clarity like I’ve never heard before form a Box Speaker and the Bass is like I’ve never experienced. No Box Boom. 40Hz all Day and I can hit 30 Hz with very little attenuation

rajugsw
oldhvymec
5,101 posts
 
To tell the truth, a single pole and open baffle is gonna be real tough.

The inside of the speaker needs to have a weir between the two. How wide that weir or baffle is, will help to focus the center. It's the rear pole that is causing the issue.  I never could get it right, BUT I did get close by adding 20 inches to the rear pole DEAPTH and quit trying to use OB for the mids and highs.. I use a dipole design just not on the same baffle plane. 

I had a hinge on the inside weir, THAT really helped to focus and help with imaging.. Get the toe in right the set the weirs parallel, they will image a lot better.

Like IRS design from infinity... the center always suffered because of the OB design and ZERO physical separation between the two speaker drivers (left to right). NOTHING, just space...smear is a serious issue THE BLOB... comes to mind... So you toe in and toe in and.. LOL it just can't work...

BUT sound quality IF you can just silence every part of the room.. Reflections are a pure nightmare with OB design and room size...SIZE does matter... BIG time...Small did NOT work for me.....

Cool looking though.. Nothing like DIY

Regards
rajugsw OP
199 posts
 
Great comments from you all (so far). Yes, I thought about using all miniDSP on all the Drivers and I have 3 Balanced version miniDSP 2x4’s that would do the job. The fact is, I’d like to utilize my PS Audio DirectStream DAC Sr. without adding another DAC in the mix (miniDSP non HD is a 48/24 A/D inside). I did start out with all active Xover’s just to get an idea on how they would sound and how best to do the Xover frequencies and Slopes.

Yes, the one big problem is OB’s will tell you immediately how good/bad your room acoustics are. You do "hear" the room. My listening space is not ideal. Basically a square room with the hallway down the left side Speaker and a pocket where the entrance is and a lot of Glass on that side.

I also tried toeing in and it messed the imaging specifically the Phantom Center and the Bass was more prominent on the right Speaker.
mozartfan
2,143 posts
 
Like IRS design from infinity... the center always suffered because of the OB design and ZERO physical separation between the two speaker drivers (left to right). NOTHING, just space...smear is a serious issue THE BLOB... comes to mind... So you toe in and toe in and.. LOL it just can't work...

~~~~~~~~~~~~~~~~~~~~~
Excellent post, 
I agree open back weakens the sound projection imaging

My Seas Thors (minus the Millennium tweeter, just sold the pair off on ebay in 1 hour), has a  *transmission design**  Has this added wall plate behind the  drivers, runs down the cabinet opens at bottom, then the sound runs up to the top with a  opening.
I took out all the white fluff JAMMED tight inside (past 20 yrs!) and now the bass/mids has exploded.
I need to place a  1 inch thick ceiling insulation behind each W18,,
IMHO this transmission design is the best for opening the speakers potential.

mozartfan
2,143 posts
 
Here is the Seas Thor cab design
Genius workmanship.
https://www.youtube.com/watch?v=UaKjlgO3IOE
jaytor's avatar
jaytor
747 posts
 
Hmm... I've only my GR-Research NX-Oticas in one room (my current room) but the center image is quite good. One thing that is different in Danny Ritchie's OB designs is that he uses a side wrong on the side of the speaker toward the center. This reduces the front to back wave interaction on this side of the speaker and may contribute to sharper imaging. 

You could experiment by talking a piece of stiff cardboard on the inside side of your speakers and see if that helps. 
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