Well, we had a quick CDaPs meeting Sunday with just myself and El Presidente.  Excellent session and great feedback on my OBs.

Eric liked some of what he heard but repeated some of what Rob had said about upper bass not coming through.  So I did switch phase on the Augies and things got a lot better.  Bass has much better pop to it and is more filled in.  I would definitely try this if you have augies or 15As to see what you get.

Second, he thought that the bass was not coherent between the augies and the Tang Bands so we played with crossover.  I had been running it at only 50 hz lately and that was too low.  We tried about 3-4 different points but settled on 70hz which is where I ended up in my initial round of fiddling.

Finally, Eric thought that the instruments were flat and not 3D sounding.  Well, lately I was experimenting with oversampling.  When I switched back to no oversampling, we got a more lifelike sound.

We then tossed in the ZMA and wow. Talk about full and detailed.  Almost wish I wouldn't have heard that  :(.  Anyway, you would have to figure out how to tame a bit of the glare to make it work long term (we tried input tubes and it seemed to shift some of the edge to a lower frequency).

So while El Presidente is not an OB fan, he was grooving after some tweaks.  he felt some music was better than others.  He especially liked Rock on these speakers.  I felt bass was good pre-phase shift.  Now its monster.

We hope to get a CDApS session in before Rob moves.  I think a winning combo might be the ZMA with Rob's DAC.

Well it was a bit of a roller coaster. It went from "please stop" to "that's the best I have ever heard that song."  You just gotta hang on.  

With somebody more impartial you can test a bunch of stuff pretty quickly.  It helps that we hear similarly.

I had been screwing around with that crossover point for 7 months.  Now I'm confident that it's set.  Also with Rob and Eric both saying that upper bass wasn't there I knew I had to do something.  I remembered maddog mentioning phase in a post and then Eric mentioned it so I said what the hell.

The bottom line is things sound better and it was fun tweaking despite being told "my kid" is ugly a few times.

A few thoughts Dave...

Yes, the typical single driver glare.  I think the formula for the TB 1808/15a xover is out there on the web.  For the augie, you'd still need to bi-amp due to efficiency differences I think, so it would probably require a different cap/resistor (maybe combo) on the 1808.

The Torri helps with the glare, but its a fine line between taming it and deadening the sound.  I continue to experiment with that, tubes and EQ in Audirvana.

Running the augies out of phase provides for better bass coherency and solves the issue I pointed out earlier in the thread where I was not getting the best imaging when running the augies.   I was just working on crossover to fix, but the combo of phase/crossover has really done the job and tightened up the bass.

One big difference Eric noted between the OBs and his 944s was the amount of air those big 15" drivers move.   The songs he tended to say "that's the best I've heard it" were big, air movers.  Rob has the trios with two augies that really pound you.  When I was at his house last time, I uncontrollably guffawed when the big/bass heavy passages played.

I have been bored dead with my music lately, but the prat I get now with the better mating of the drivers left me listening for 4 hours the other night - to the same stuff, but taping my toes and digging it all over again.

I mentioned this earlier, but Eric also enjoyed rock on these speakers.  Not exactly a known OB strength, if I remember my research.  Still, AC/DC all night long and one other song I don't remember sounded really good.  Good instrument separation.  Kick drum chest impact.  Rock!

The ZMA was fuller, more detailed and really changed the sound and the imaging of the speakers.  I loved what it brought to the table, but made me also think that the speakers produced too much pressure for my 16X12 room.

I never had good luck with a sub, but I never had a good one to experiment with.  That's what lead to one augie, then one augie became two, then two augies became duo's with the 1808's, now I am thinking about trios.  Soon I will be sitting in a little 5'X5' space with speakers all around me in a musical stupor

Yeah, it all adds up.  I got them before he had to increase the price.  Maybe $440 shipped?

I still intend to get a single 15a to run on my second system summed to mono to see how it sounds.  I have a baffle cut from my early experiments with the augie that I am pretty sure I could use.

Rob drives his 4 augies with two plate amps.  I am using the crown 1000 amp.  It's more than enough for two augies.  You might go up to a 1500 for 4.

I am surprised that el presidente has not chimed in.  A lot on his plate these days.

I have run the augies off the Torii as well and it didn't sound like the bass was soft or anything.

But the Augies are 89db and the 15a is 98db or so, so they mate with the 1808 better.

I checked parts express.  They have like 10 versions of the 15a now.  Varying sensitivity and QTS.  Looks like the basic unit people use in OBs is down to $59.  

I run two Augie's in parallel in each Trio baffle, i.e. 4-ohm load per channel - four Augie's total.  I drive them with a Crown XLS-2500.  The "signal present" light on the Crown "flickers" off and on at normal listening levels.  When the signal present light is on solid, and the -20 light is flickering - things are starting to get serious.  And I run the Crown's input attenuators at only about 70% of wide-open to boot.  Only once or twice have I endured the -20 light on solid.  At this point, my house was being lifted off the foundation with each thud of a kick drum.  I am using Audio Nirvana wide-banders in the middle spot of my Trio's driven directly, full-range(no xover high pass) by my Torii III.  If there is a better amp for wide-banders than the Tori III - I haven't heard it yet.  The treble shunt on the III allows you to really dial-in the rising frequency response of nearly all wide-banders to "just right".  Not to mention the Torii's output impedance is complimentary to the typical wide-banders impedance in the 40-60hz range, which seems to really put some nice flesh-on-the-bones weight to the music.
I am more "satisfied" with my systems sound now, than ever before in nearly 40 years of actually pursuing this hobby.  It has/is taking a long time for my "what if I try this" cognitive dissonance to go away though.  I guess that's why I have six different sets of speakers, and working on #7.  But with each cable, amp, speaker combo I try - so far, I have come back to the OB's with Augie's and wide-banders driven by my Torii III.  Sooner or later I just know my brain will finally "accept" what my ears are hearing!!!
Yes... messing around with the xover point, phase, etc. is essential to getting this OB combo dialed-in.  But boy when you do - hang on, cause the sound is going to blow your mind.  

Sorry for chiming in so late - I just have a lot going on lately, and not much of it good  unfortunately.

Anyhow - no, I don't care for OBs

Yes, we did get Pals setup tweaked a little better (OK, a lot better). I really love how effective we are when we just say the first thing that comes to mind - it's usually correct. I learned that from Steve; for the longest time I would keep my thoughts to myself for fear of offending the gear owner (or in Steve's case the gracious builder), but I've listened and learned.

I don't think Pal gives himself enough credit for how good his ear is - I'm constantly impressed with how he takes my suggestions and runs with them and on my next visit the sound is pretty stunning.

So as I said, I don't care for OBs too much - and Pal's setup is OB, *and* full range drive with the full range driver shout. The ZMA was absolutely stunning, and I kept saying "I'm so glad I got this amp" - I just can't love those speakers. The sound was very shallow to me...for those of you who shoot any style of SLR camera where you can adjust the aperture - the OB sound in  this room sounded like it was focused only 4' deep but spread wide and tall; just a really shallow plain of focus. The high frequency didn't have the extension and spacial cues that ProgRob's setup has (which I truly love) but the bass was nice once we got it dialed in and got the crossover in this setups sweet spot. I was honestly blown away by how good anything Rock sounded - I've been listening to AC/DC for 30 years, and was stunned at the instrument separation and clarity, all without the piled-on congestion I'm used to hearing from rock albums. Every guitar had its space carved out, the vocals weren't buried behind instruments, and the drums were visceral and punchy. PRAT all over the place once we got the bass sorted out...before we figured that out, it was a lumpy, disjointed mess that irritated me and made me want to track-hop around "looking for something better". Afterwards, it was a real room filling sound.

What I miss is the spacial cues that traditional boxy speakers give you, at least in Tom's well setup room. Yes the OBs filled the room with sound tall and wide, but I didn't feel like I could hear the room the music was recorded in; I told Tom it sounded like I was in the Lobby of venue and they left the double doors open - I could hear everything perfectly, I just wasn't "in the room" with the music. Part of why I enjoy going to Tom's place so much is he's got the room setup way, way better than I can setup any room in my house - I will never get that quality of sound without gutting a room and starting from the studs, or at least bare walls out, dedicated audio room - golden ratio and all. Till then, I live vicariously through Palomino's room.

Now that I've bashed his new child(speaker) to death, I will say he does a beautiful build. I'm picky and his work was pleasing to look at and well thought out - I would have thought they were store bought "boutique" builds if I didn't know Tom's build style.


So I brought my ZMA back home and eventually set it up and listened a bit. (shrug) - I realized how loud those OBs are - I love my clarity, especially with the PS Audio Bridge II on my Direct Stream DAC being fed by Roon - but I miss his wonderful little basement listening room.

almost ALL speakers sound better pulled out away from the wall behind them - at least to a point.  With OB's (or any bi or dipole) this is "a requirement" - they have to be able to breath.  If you have a small room, or need to put your speakers close to the wall behind them - OB is probably not the way to go.  
My OB's are 6 ft. out away from the wall.  My experience with "recording room" sound has been the opposite of LR's.  I think this is mostly a crossover-less thing, not necessarily just an OB thing, but I can hear reverberations and slap-echos from the recording studio that's buried in recordings that I've heard 100's of times before and never heard until I was crossover-less and OB.  
After listening almost exclusively to box-less speakers for the last 3 years... there are very, very few box speakers that I can't immediately hear/detect "the box" coloring the sound.  That said, I discovered an audible resonance in the back braces of my OB's awhile back too, that I had to address with additional bracing/mass.

I double checked and I am 5' from the back wall.  

Maddog is your soundstage primarily behind the speakers?  Mine is and could be what Raven was having some issues with.  But the depth of the soundstage behind that is big.

I will say it took some time for me to adjust to where the soundstage is placed.  

I am not sure I can go back to boxed speakers.  It takes me some time to get used to them in my cottage setup.

Well I think I figured it out last night.

I think Eric heard a pressed back and flat soundstage because of where his head was positioned.  In general, he sat in the listening chair and I was behind him in another chair.

Last night I noticed that the listening chair was out of position.  At least a foot back.  I moved the chair up and got a great 3D soundstage.  I moved it back and well, not so much.  I went to where I was sitting and it was better again but not great.

I didn't think I had room nulls with the OBs.  I definitely did with box speakers. Huge nulls.  Anyway I suspect there is a front to back sweet spot for the soundstage just as there is for the sides to side for imaging.

I'll keep testing.  I may even break out the mike to see if I can measure it.  I definitely could with my box speakers.

Rich, what OBs are you running?

Pal, My OB's are home made using Wild Burro Audio Betsy's, the same ones Randy uses.  The woofers are 10" from MCM.  You can see pictures in this tread.   https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1461890060/0 which is in the user picture forum and named My Zen Room.  My amp is a Decware SE84UFO2.

That Redbook to DSD sounds interesting - it's the basis for how the PS Audio DirectStream DAC works, turning everything to DSD and then multiplying everything by 20X or something like that - then doing any tweaking (volume etc) at those huge math numbers. I think it allows for more natural smoothing of what's already there...whereas oversampling to me feels like it's smoothing while adding harmonic jaggies that harsh my mellow.  ;)

As for the sweetspot and "dropouts" - all rooms will have them, except maybe an anechoic chamber. It might not be noticeable big (volume) dropouts and hotspots like low frequency would produce, but there are all sorts of canceling and comb filtering and other badness going on. Probably more so with Open Baffles because you have wave fronts from both sides of the driver to contend with.  Add to that, you have two drivers on one baffle, they'd have their own comb filtering where the waves intermingle between the baffle and your seating position. Plus the waves from left speaker to right speaker. Lots and lots of reasons (waves/reflections) for audio cues and apparent location of soundstage/instruments to get pushed around.

I just call them as I see them - you're the clever one moving sound treatment and seating position around to make it sound better than "good".

IMHO - with Open Baffles you now need *even more* diffusers to widen the sweet spot and localize the sound. Speaking of which, I'm hoping to spend some time in the garage this weekend mounting my fleet of styro diffusers to panels to group them and more easily suspend them....maybe it's time we put some of my diffusers on your ceiling...remember that idea popped into my head while we were listening? I'm thinking my audio-intuition was telling me something about your room.  ;)

I'm still thinking about folded horns and single drivers - but I still fear the shout - if I were to go single driver, I'd probably go something all bendy like this:




Oh, one last thing - I really like that Crown with the built in crossover - IMHO, if I were to do supplement a full range driver setup with subs, I would do two small subs using an amp like that, and the subs would be placed directly to the left and right of the seating position. I've found (and other's measurements have shown) that a dual sub setup with the drivers around the middle of the room give more even bass response at the main listening position.

I have so many ideas - I just need a dedicated listening room - having the redhead move in with me really nixed that completely. I may have to wait till I move to a nicer/bigger house.  

Well, you'll have to come back and see if you agree what I am hearing is better.

The guys who are touting the DSD conversion have DACs that can go to 128 and above, but I think its a lot smoother with 64.  

I am thinking about doing a wall of diffusers from Styrofoam.  Basically make my whole front wall a QRD.  Darrell Hawthorne sent me a how-to in an email I have yet to dig out.  It's using those 2" foam insulation panels like you experimented with before.  He basically cuts them with a table saw though instead of a hot wire cutter.  Messy but less work.

I'm working in the garage this weekend - I'll see if I can clear of the table saw and maybe finish up some of my diffuser projects as well.

Pal.... soundstage position and depth.... it has been my experience that moving any speaker out away from the wall will move the entire soundstage "rearward" and add depth - to a point.  And more so with some recordings than with others.

Think about how a performance is recorded.. at least a minimally mic'd one where the engineer attempted to capture a "realistic" facsimile of the performance (this does not apply universally to close-mic'd events if there was a mic stuck in front of every instrument and multi-tracked to later be mixed down and mucked with).

If you go to a concert, you set out in front of the performers.  the Performers are "usually" on a stage, slightly higher than you, and always in front of you.  The main microphones will be in front of the performers, usually with some hanging from above to capture reverb, ambiance, room acoustic, etc.  Usually the mixer/producer will use these tracks to add ambiance in varying degrees to a recording depending on how the capture from the main mic's turns out.  But the main microphones are "between" you and the performers - This Is A Key Point.  In our playback system, ideally we want our speakers to take the place of the microphones where the recording was made.  This means, that for the most part, the entire image illusion should be "behind" the front plane of the speakers(microphones)......  think about it!
If the reproduced image is in front of the speakers, then this would imply that the performers were nearly in our lap if we were there when a performance was recorded - not very likely.  Even studio recordings, of high quality, where the recordist was trying to capture "the event", the illusion of the performers should usually be "behind" the speakers, because if you had been there when it was recorded, the performers would likely have been in front of you and the microphones would have been in front of the performers and between you and the performers.

One of the best examples I can think of, off the top of my head, where information about the actual recording venue and how the performers and recording was setup is available(you can view it), is the Cowboy Junkies Trinity Sessions, and Trinity revisited.  If you play this music on your system, and the illusion of the performers are "in front" of your speakers... then you can rest assured that your system is not "accurately" portraying the recorded event as captured on the CD/LP/wav file, etc.

Hey Pal,
I was looking at info on QRD Diffusers, and I ran across these pictures. I remembered what you said about making your front wall all diffusers, so here you go.
Randy

Thanks for the photos.

I found Darrel's recipe.  It's 2" rigid insulation panels cut to various depths in a prime sequence with fins made of Masonite.  You can cut using a table saw.  Evidently using a table saw is easy but pretty messy cutting the insulation. Then paint.

If my measurements are correct I could do my front wall for around $200.

Here is Darrell Hawthorne's room:

http://www.hawthorneaudio.us/forums/viewtopic.php?f=21&t=4641&start=45

He has another treatment at the center of his room but the sides have the qrd's.

I still feel the poly-cylinder is just a quick and dirty "diffuser". It really does nothing in the "time domain" and simply scatters the sound. I think you could do so much better with your slat-wall diffusers, the deeper the better.

Or if you want to stick with the styro and dividers, I'd do a nice big Prime 29 using the 2" insulation. But I'm still a firm believer in the sound waves picking up the tone of what they bounce off of, and I'm worried the styro-sound might accentuate your single driver shout.

But what do I know.  ;)  (shrug)

BTW, I saw a home made hot wire cutter on ebay that was made of copper pipe that I think I could build.

I had this nice long post typed out, and somehow lost it when I went to post.

Short version - I'm going to chime in on Pal's thread rather than start my own for now, since our Audio Projects are often paralleled, if not entwined.

I'm getting back to my never ending (and never finished) diffuser designing and building. I seem to spend more time making room in the garage to work, then adjusting/tuning tools and building jigs than actual building of anything!

To start, I took a pair of CNC Hot-Wire cut Styro diffusers and framed them up tightly in a poplar box. It's only 6" deep as that's what I was able to get inexpensively. I was originally planning on making them 8" boxes and lining the back with acoustic blankets recovered from my 15 year old CWAL bass absorbers I recently retired....but that extra couple inches added quite a bit of cost and I'm pretty damn broke right now, trying to work with what I have around rather than buy more wood if I can.  I'm a believer in that sound reflecting off an object takes some of it's sound with it. Sound bouncing off glass has a high frequency enhancement that I don't care for, and something similar with Styrofoam diffusers.

That said, these are some of the diffusers that I dragged out to Palomino's listening room as well as ProgRobs listening room, where we had some amazing CDApS listening sessions where simply placing these styro diffusers in key places aided in PRaT and made the music really *involving*.  I employed a lesson I learned from Steve, where you don't simply listen to the music, but watch the body language of the listeners - and it was clear how much involving the music was with just these four lightweight panels leaned up against the walls.

So I bound them together in this frame in hopes of using them more effectively either in my "listening room"/theater and/or my spare bedroom which has become sort of a home office. I figure my 18 year old original Zen amp, some efficient speakers, and walls covered in diffusers might make computer building and whatnot more enjoyable.



So much for this being a short post.

More pics of diffuser projects to come. My next one, an all poplar 24" X 24" X 6" QRD is coming along nicely. I'm going to slowly build up to my ultimate design which will be these HUGELY complex QRD diffusers that will help scatter and diffuse between 350Hz and 6880Hz.

The more I build, the more I appreciate how well thought out the Decware diffusers are. They do exactly what they need, at a great price, and shippable package.

Lonely Raven, A couple of observations:
Don't lay your grinding wheels horizontal like that, you are inviting cracks.
Your reloading bench is a mess, organize it up please! The brass needs to be handled carefully.
You really need to put the door on your fuse box. Haven't you watched the videos of fireballs from exposed fuse boxes. I have to test out twice a year on that stuff and I don't even plug a light into the wall at work.
A clean and organized shop is a safe and efficient shop. Put things back where you got it from and it will be there when you need it again.
Oh yeah, your box sound catcher thingy is kind of cool in a mad scientist way.