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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
jaytor's avatar
jaytor
765 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. 
timlub
2,040 posts
 
Seal the midbass in a small stuffed box, change the crossover between the mids and woofers to 120. 2500 is fine on top. You are getting that free air woofer out of the vocal range. Leave the woofer free air. Everything will snap into place instantly.  You can dial it in and try it without the midbass baffle, but you will have a hole in your frequency,  the Dynavox won't go down to 120 without the box.  
Be careful experimenting,  use low power, the Dynavox have an xmax of 2mm.  They won't like going down in free air.  
jaytor's avatar
jaytor
765 posts
 
Just noticed that autocorrect changed "wing" to "wrong" in my post. Meant side wing on the inside side of the speakers. 
atmasphere's avatar
atmasphere
11,841 posts
 
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.
You mentioned center fill as an issue. The way an OB system is supposed to work is that the rear firing information bounces off of the wall behind the speaker and thus arrives at least 10mS later than the first arrival.


If it does that the ear uses the delayed information to echo-locate, IOW to help out the sound stage. If it is less than about 10mS then the information contributes to harshness. As a general rule of thumb you want such a speaker to be at least 5 feet from the wall behind it. If less than this it won't image right because of the reasons I stated.
roxy54's avatar
roxy54
8,012 posts
 
I wonder if the center image problem is because of the deep walls on either side of the midrange drivers. I have never seen an open baffle speaker that looked like that before. 
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