Awesome, thanks!
I've done some preliminary experimentation and built a small H-frame just to toss them in for a few minutes, but I didn't want to get too far into it before discovering that there was some pitfall that I hadn't considered.
What about Dayton RS-150 for midrange drivers?
Should there be anything special to look for when shopping for OB drivers, or am I basically using the same criteria that I'd normally use (linearity, low distortion)
Edit: or would the RS-100 be a better choice?
Why do you want a WMTMW? I don't see any acoustic advantage in a dipole woofer H-frame in mid air, but real structural problems if you want the baffle to narrow around the Neo3 - which you should. I would even question a necessity for the upper midrange driver. There are reasons why most newer dipoles end with the tweeter on top.
Rudolf
Why do you want a WMTMW? I don't see any acoustic advantage in a dipole woofer H-frame in mid air, but real structural problems if you want the baffle to narrow around the Neo3 - which you should. I would even question a necessity for the upper midrange driver. There are reasons why most newer dipoles end with the tweeter on top.
Rudolf
Well, what I don't have drawn in the rendering is the upper frame and lower connected with 5/8ths threaded rod. It won't be supported at all by the mtm center baffle.
As far as sonic advantages, I'm really just borrowing from two designs that I've seen, James Trexx's and the aristoteles. Its a grand expirement. What I'm looking for in having the upper mid bass h frame is really just "sonic size" and the visual impact. Wood is cheap and I've got the drivers, so unless there's some kind of "disadvantage" that I haven't considered or don't know about..I'm going at this with all guns blazing, lol.
Quick well done to Superlian..!
Great design flexibility choices and execution.
The comments regarding absorbers is a wise one... I made some simple frames full of fiberglass roof insulation and covered them with fabric socks.. With the right sock material they would disappear in your room. Mine where only 80 mm deep and made a huge difference to the mid and top end of my OB's... One behind and one beside each speaker.
Dean
Great design flexibility choices and execution.
The comments regarding absorbers is a wise one... I made some simple frames full of fiberglass roof insulation and covered them with fabric socks.. With the right sock material they would disappear in your room. Mine where only 80 mm deep and made a huge difference to the mid and top end of my OB's... One behind and one beside each speaker.
Dean
Thanks, that is always an honor if somedody takes over bits of a design. The curved panel works pretty well for the midrange. But as we "speak" it is about to change although I will probably keep some curves. Version 0.61 is in the works...going 4 way. And as Rudolf pointed out, ending with the tweeter on top.
If you want sonic size, I would add two monopoles to shake the house.
To be fair, it was really your Aristoteles that started me in this direction and James' The Gate that got me thinking that I could use some of these old low Q woofers for midbass duty. I'd love to get some of the scan-speak midrange units, but they're mad expensive.In making the change over to open baffle and dipole, I'd really like to just run the two main speakers from 60hz on up. I've got decent subs that'll cover everything lower than that. There's plenty of house shaking even with what I have now.
As far as tweeter on top (forgoing the second set of MW, I'm guessing is the suggestion) is there a sonic advantage, or is the idea that it's wasteful? By sonic size, really what I mean is just lighting the whole wall up with sound, not necessarily shaking the house. I've always had trouble with sonic size, where it always really feels like you're "listening down", so I was going for symmetry and lots of baffle area and having that top H frame being pretty much against the ceiling.
Have you tried this and it sounded terrible or didn't measure right?
OK, but one last answer to DrDyna, maybe he should open a dedicated thread.
The symmetry that buys you vertical control with normal speakers is not really required with dipoles. There you already have a somewhat narrower dispersion. If you now go with mtm you could run into vertical response issues at shorter wavelengths. Also, the two m's could outrun the neo3 and so you will have to decrease the output and the spl advantage is gone with more cabling and amps and less mechanical stability.
With a LX521 or NaO Note type speaker there is no "listening down" issue.
If you really want to go wmtmw then it is better to go 8-4-t-4-8" in a simple baffle (maybe hourglass shaped) instead of the H-frame. But the neo will most likely be again the bottleneck. If not in SPL then in size (too narrow vertical response resulting in sharp interference nulls at cross over F).
The symmetry that buys you vertical control with normal speakers is not really required with dipoles. There you already have a somewhat narrower dispersion. If you now go with mtm you could run into vertical response issues at shorter wavelengths. Also, the two m's could outrun the neo3 and so you will have to decrease the output and the spl advantage is gone with more cabling and amps and less mechanical stability.
With a LX521 or NaO Note type speaker there is no "listening down" issue.
If you really want to go wmtmw then it is better to go 8-4-t-4-8" in a simple baffle (maybe hourglass shaped) instead of the H-frame. But the neo will most likely be again the bottleneck. If not in SPL then in size (too narrow vertical response resulting in sharp interference nulls at cross over F).
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Thanks 2Pi. The beauty of active open baffle I guess is how simple (read: easy to make new ones) the baffle can be, so I might go through quite a few iterations before I'm happy. I understand what you guys are saying about the design that's similar to James Trexx's Gate and I could run into issues, but I'd like to at least try it and measure it to see what I get. If the Neo3 ends up running out of gas or has dispersion issues, it would be fairly trivial to swap, or perhaps even add another one?
Gainphile, sorry about mudding up the thread with all this silly talking! If it's any consolation, your 8 channel Class D build is what really inspired me to think I could afford to go fully active and build a massive open baffle in the first place
Ok, I'll stop, my next posts in here will be pictures and measurements of whatever I end up building. Cheers fellas, and thanks for the info
DrDyna, I am using MTM with my AINO 4-way dipoles. High-Ms are xo'd now 550-3100 and when playing sine above 2kHz I can hear comb filtering, but it is not noticable with music. My T is Fountek NeoCD3.5H which is also very narrow vertically. But, I've been thinking about to set it to WMT just for testing how it sounds. It is easy with minidsp.
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Here are a few pics of my most recent OB speakers incarnation:
Design goal was to make them fit as well as possible into a normal domestic living room (i.e. spouse had to approve finished look). And to be able to live without additional acoustic room treatments. Angling in design makes them workable close to the front wall.
W-baffle with 2x Acoustic Elegance DP10s, Seas W22 paper excel mid and SS illuminator tweeters. Each woofer driven by 200W, with active crossover to mid/top and another 200W amplification. Passive filtering between mid and tweeters.
More details, reflections and some measurements in the separate thread - http://www.diyaudio.com/forums/mult...ffle-project-ortho-acoustic-design-ideas.html.
/Mats
Design goal was to make them fit as well as possible into a normal domestic living room (i.e. spouse had to approve finished look). And to be able to live without additional acoustic room treatments. Angling in design makes them workable close to the front wall.
W-baffle with 2x Acoustic Elegance DP10s, Seas W22 paper excel mid and SS illuminator tweeters. Each woofer driven by 200W, with active crossover to mid/top and another 200W amplification. Passive filtering between mid and tweeters.
More details, reflections and some measurements in the separate thread - http://www.diyaudio.com/forums/mult...ffle-project-ortho-acoustic-design-ideas.html.
/Mats
The link to my AINOgradient project doesn,t work. A new try here http://www.diyaudio.com/forums/mult...aborative-speaker-project-21.html#post3527056
Directivity measured from 1,5m distance, 9ms IR window
Directivity measured from 1,5m distance, 9ms IR window
This Supravox dipole also nice having "Un 285 GMF, un 215RTF et un TW2"
www.audioatrium.com :: Voir le sujet - Open baffle
www.audioatrium.com :: Voir le sujet - Open baffle
