Open Baffle + Bass Reflex HYBRID

The Radian Be sounds pretty ideal. Not the current budget, but the Al upgrade path is intriguing. Analytical is less my speed, but not sure whether the Audax would be too mellow. I'm used to an XT25TG.

How about the midrange? Wondering how the 15OB350 across that range compares with the PA310 and Radian mid. 🙂
 
All three have fantastic midrange. The 15OB350 / Cottonwood combo have the slight disadvantage of floor bounce. Which IMHO isn’t that much of an issue per se but in general a midrange still sounds better raised up off the floor.

Which you can certainly do in your own implementation.

The 15OB350 has more surface area and more ‘heft’. Of course you can EQ it any way you want but in general I feel the larger surface area AND not carrying the burden of low bass gives it an advantage over the others.

You can’t go wrong with any option but if this were my sub + dipole system I’d pick the 15OB350 with the SB Be tweeter, raised up so tweeter is at ear level and woofer is off the floor.

I’d use shallow wings to pick up a little bass extension to be sure to reach down to 60 and you should have an amazing system.

If you’re not into high SPLs you could skip the wings entirely and EQ boost probably 6dB (?) below 100Hz and the 15OB350 could keep up just fine.
 
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So you'd be inclined to basically make a Cottonwood with the tweeter and 15OB350 raised? If the tweeter were at 39" the middle of the 15OB350 would be approximately 25" off the floor. That be enough? Swiveling it the other way around (woofer on top) would make it a good 60" tall if the 39" tweeter were maintained (but might sound great).

The wings to reinforce the bass don't cause overly problematic cavity resonance issues? I'm still learning how these aspects relate to each other. 🙂
 
While punching in BOM costs I noticed that the Audax TW034 is quite reasonably priced, but by the time the expensive Janzen waveguide is procured the combo costs essentially the same as the SB TW29R and waveguide you used in the Walnut Dipole.

An attractive alternative for the Flanaganster? An option for a budget Cottonwood?

Moving up the chain, it looks like the Satori TW29TXNWG-4 Textreme Tweeter with Waveguide is shipping now. Might slot in as an upper medium-level alternative to the Be? I've been concerned by the description of the latter possibly being clinical.
 
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This website with 3D printed waveguides is the answer (you can get the files, send them to a person who sells 3D printing on Etsy or similar sites, and pay that person to make them for you; or you can follow the waveguide 3d printing threads on this forum).

For the 15OB350 you really want an 8" or absolute minimum 6.5" waveguide. Scroll to the bottom of these pages for example:

https://www.somasonus.net/sb-acoustics-sb29sdac

https://www.somasonus.net/sb-acoustics-sb26

https://www.somasonus.net/satori-tw29tx

Textreme sounds promising. Pick a tweeter you like and away you go....
 
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I'm currently sans 3D printer, so really appreciate the ideas about Etsy or other groups. I didn't plow through the >100 page thread on printing them yet, but think it's amazing that somasonus.net has taken the time to develop so many waveguides!

When you say 8" waveguide to pair with the 15OB350, does an oval version count? How far apart would the acoustic centers be? I'd like to mock that up in more fancy cardboard. 😉

How different would your Flex Eight settings be for the TX version vs the Be version? I'm cautious about mucking up your carefully crafted designs, yet the cost differential isn't insignificant. The imperfection of my room and treatment is likely larger than any gap between those drivers!
 
Oval version is fine. You can look at the drawings on the page to see the dimensions.

If you're going to do this, you should get some measurement software and a mic, then adjust things a little. Not difficult. You should be able to easily tweak the EQ to your liking.

You download the 3D printer CAD files from the site above, send them to the Etsy vendor (there are lots of them) and they print and ship you your waveguides.
 
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You can’t go wrong with any option but if this were my sub + dipole system I’d pick the 15OB350 with the SB Be tweeter, raised up so tweeter is at ear level and woofer is off the floor.

I’d use shallow wings to pick up a little bass extension to be sure to reach down to 60 and you should have an amazing system.

If you’re not into high SPLs you could skip the wings entirely and EQ boost probably 6dB (?) below 100Hz and the 15OB350 could keep up just fine.

I didn't see a dedicated Cottonwood thread, so I'll leverage your quote above in this one if that's ok.

Thinking about raising up the 15OB350, I decided to see what the minimal volume might be. These images will again take some serious imagination--the stand would be robust, the baffle about 1.5" thick, etc. The tweeter zone also was a quick eyeball guess, then I retroactively tried the wider 8" oval waveguide, so looks very cramped. The 15OB350 diameter as shown is back-mounted, but that could be reversed of course.

Would one of these 2 "wing" orientations be preferable, or no difference?

Is the wing feature larger than needed? As shown, it's a maximum of 14" from the baffle front.

Common airspace:

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Or "segregated" airspace--kind of keeping the rear tweeter zone separate from the woofer. This might be more relevant if there were a midwoofer above it, I'm guessing? Anyway:

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I prefer the common airspace. Acoustically this design should perform well. It will roll off at around 120Hz so will need a little boost around 80 to meet the crossover point of 60. Should be no problem.

Cosmetic comment: it seems to me there's a risk of this looking like a bird or an egg so you’ll need to play with the design so as not to lend that impression.

Personally I think you could mount the drivers on a single slab of wood 18” wide without wings, that goes all the way to the floor, and you’ll get adequate bass extension with modest EQ. Just my 2 cents.
 
Well, aesthetic preferences as always run an extremely large gamut of opinion. 😉

I may well end up executing some variant of a big slab with drivers stuck on it, but if so, it would probably be white and taper to the top. I can certainly understand and genuinely appreciate the live edge look as well as other large surfaces of wood. It's just that our household preference is for visual simplicity for big objects in the room--more disappear than being the show, as it were.

As an example, my recent dual opposed servo subwoofer build isn't a big box or figured wood coffee table, but rather a clean white column that basically acts like 2 subs in the room and is an independently functional lamp. Different people, different preferences!

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Before I build something I like to explore a wide range of ideas (and have probably already driven Perry nuts by now--sorry! 😏). I've been surprised countless times by how multiple concepts interact and spark new thoughts, and by what I've learned by mocking up 100% size/shape/proportion vs by only using my imagination or staring at CAD models.

Perry, thank you again for your patience and generosity with your time and designs!

Returning to this thread, my friend is quite likely to build the Flanaganster in a fairly stock form, or perhaps with a 15OB350 down below--TBD.
 
That's certainly an innovative way to mount them, but I have to ask--how does it work having the OB sections that close to the wall?

The speakers also appear to be at borderline nearfield listening range, which makes this multiple driver setup even more challenging to understand.
 
He didn’t ask me where to mount them, he just hung them and told me later. So they are about 2 feet too close to the wall. They sound great anyway. The other recording engineer commented that they don’t have “corner mud” and that the bass sounds fantastic.

There’s no issue with being too nearfield, there are only 2 drivers operating above 200Hz anyway and there are no serious lobing issues at any realistic listener position at the 2K crossover frequency.

One of the reasons is the double steep shelf filter crossover I implemented via FIR which only has max 1/3 octave overlap between the drivers at 2K. The FIR corrects timing and achieves flat phase.
 
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Perry,

Thank you for your openness with information. You are a true value to the open source DIY community.

I had a question regarding proximity of dipole speakers to a rear wall. I had always been under the impression that having a dipole speaker in our house was an impossibility, due to the fact that we have long and narrow rooms. I can't have anything sticking out more than 24-26” from a wall.

1. What is the recommended distance between a Full range dipole (25hz) to a rear wall?
2. What about 100hz+?
3. 200hz+?
4. 400?
5. How much do side-walls matter? I have a wall ~6 feet away on one side but the other side of the room flows into the rest of the house, with the next wall being ~20’ away.

I’ve been diving into this thread (and the idea of using a Coaxial) because I had been planning on building a Martin King style transmission line subwoofer/midbass (to currently mate with my Philharmonic BMRs), but also, pragmatically, to give them a stand to sit on. I'd been hoping to repurpose the TL in the future to be able to accommodate either A. A HLCD, or B. A Dipole as my budget and/ or house changes. I was drawn to the idea of your bass reflex hybrid as that is essentially what my TL was going to accomplish.

More and more I'm subscribing to the idea of a 2 or 2.5 way of a HLCD or Dipole covering a wide band of mid-range to the end of my hearing (15khz?). On the 2 vs 2.5 debate, I'm torn on whether to take advantage of multiple subwoofers for the bottom octaves where they can't be localized. I've realized that trying to stretch to 25hz severely limits the choices for a TL as they directly run into Hoffman's Iron Law. For me, the key trade being size vs sensitivity. Tuning for 40hz+ on a TL opens up the speaker choices 10 fold and drastically reduces the line length.
 
"... due to the mass quantities of critters that infested everything back then quickly eating/whatever the cotton."
When I lived in Paraguay, late sixties, they used to sell an US made insecticide branded "Real Kill" a fat brown glass bottle with a spray pump on top, never ever saw again such a fulmineous death of any bug, ant, mosquito, spider, roaches, everything. Later I learn It contained DDT, so not an isecticide but kind of a carbon based life forms eliminator 😊
 
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