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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

Showing 8 responses by rajugsw

rajugsw OP
199 posts
 
Excellent comments from all of you once again.

Here's my responses (so far) and thanks for the good advice :

  1. The side wing (a la NX-Otica's - Danny Richie - I watch his Video's too) idea is one I will try 1st and foremost. Makes sense and he gives an excellent explanation why as you mention too. It's the center focus problem. I have enough material that I can temporarily make a side wall on top of the 1.5" thick side panels of the H-Frame Woofers.
  2. Build a box around just the Midwoofers leaving just the 12" Woofers and the Tweeters Dipole. Changing the crossover points from 250Hz - 2500Hz to 120Hz - 2500Hz won't be hard. I have lots of Inductors laying around that I can cobble something together. Lowering the 12" Woofers LPF  to 120Hz is a snap with miniDSP.
  3. Placement currently is 5ft. exactly from the "front" (TV) wall to the back of the H-Frame Subs (5', 9" to the Midbass/Tweeter Baffle). Right side is only 2.5ft. from the room's side wall and the left side is a whopping 7", 4" from the entrance/side pocket opening/WINDOW (I have to draw it out for you Guys), Also on the right side the Speaker face a Hallway. Also the swinging doors to the kitchen are wood in a glass frame window embedded. I'll take some pics and a floor plan with room dimensions.
  4. Toe-in on most box Speakers friends have lent me gives me a great center phantom image when placed straight out into a room except for a pair of KEF R3's that worked best with about 10deg of toe-in.

Thanks again for the kind words of encouragement.

BTW, I'd seen a lot of OB designs that that either integrate an H Frame stacked or not stacked Woofer cabinet below the OB Panel so my panel was tall enough (barely) to accommodate. The difference is I have no top brace/shelf in my design.

I also saw a Video with Clayton Shaw (Spatial) who suggests the upper Woofer be crossed over higher while the bottom one is X'd at 90Hz.

Baby steps but I can hear the potential.
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.
rajugsw OP
199 posts
 
@jayfor Diffusers are next on my list. I have 6  sponge type absorptive panels at the 1st reflection points in the room, above the listening couch, and as you see in the pictures, placed in the corners like Bass Traps (which I know they are not). two 20"x 20" behind each Speaker may do the trick. If not, it's Amazon so I can return them & get my money back.

I'll let all of you know. Thanks again. Great tips so far.
rajugsw OP
199 posts
 
@pekri. My Wife would kill me but yes, I did read Nelson Pass' article  a while ago. Interesting design and I'm sure it's a mindblower.
rajugsw OP
199 posts
 
I added a side panel (behind the baffle) on both Speakers facing inwards to each other with acoustical foam. 10° of toe in and the Phantom Center is back baby !

It's not razor sharp but it's better than it was yesterday. The Treble is a bit subdued now. But that's to be expected. My ears will adjust. To me when someone says the Treble or the Speaker has lots of air, that's a hot Tweeter. This is great when you want to hear the Fart of a Knat, but to my ears it can be fatiguing. No Tinnitus here, just 51 1/2 years of age.

So long as the vocal sibilance's stay dead center along with the Kick Drum & Snare Hits, I'm good. I have some mono DSD files legally purchased/downloaded and will try them out tonight. Right now, it's a 70's Vibe, CSN, & Y, The Eagles, James Taylor, Joni Mitchell, Carole King, and whatever else I'm either Streaming (AmazonHD/Bluesound Node 2i) or Spinning (SACD/CD).

Thanks for all the encouragement and advice folks. I still have tinkering/tweaking to do. 


rajugsw OP
199 posts
 
Again, my Wife will kill me if I DIY’d 3 PVC pipes taller than the Speakers and placed one in the middle of my room (see pic link on my original post).

I am building some calculated Diffusers from 2x2’s cut to specific lengths using QRdude and chose the design frequency of 300Hz (human voice). No clue if I’m gonna fail or pass but I have lots of 2x2’s doing nothing in my garage and some cheap thin plywood to glue the pieces on to. I’ll try them behind the Speakers first (plan A), then replace the foam panels at my first reflection points with the diffusers if plan A doesn’t work (plan B).

Or build more of the diffusers and reuse the foam panels as fake Bass Traps that will raise the height of my current.

Is my frequency selection correct since it’s the female/male voice that’s the problem ? Drum Kicks/Snare are pretty centered.
rajugsw OP
199 posts
 
@quadprod :

You make some excellent suggestions regarding using active X-overs and Finite Impulse Response Filtet also can more precisely help with some of my issues.

But as I’ve stated earlier, I don’t want to feed the Analog output of DAC into another DAC (of sorts).

Fixing my room problems for me is the key to getting that damn center image sorted out.

I’m almost there. Built a 2’x4’ Skyline Diffuser for the back wall behind the sofa and an building two smaller 2’x2’ Skyline Diffusers for behind the Speakers (preferred WAF) or on my 1st reflection points where I have absorbers currently.
rajugsw OP
199 posts
 
@coltrane1 That's so cool. My woodworking chops ain't the greatest but all my DIY Speakers have always had a DIY look and feel to them. Not by choice. I am not a Carpenter (but I wish). Here the rear wall Diffuser just completed and hung today. Two more smaller one's are going up this week either at the 1st reflection points or behind the Speakers on the front wall. 

Phantom Center is much improved but add smaller diffusers should tighten the Phantom Center. Or that's the hope anyway.

https://photos.app.goo.gl/bJQNygLXcWffuGKg7
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