I took a stab at estimating the trapezoid panel used on the Tide for the LM10n and simulated the response on Edge. It would seem this would work for 450-2500Hz. I need to run the simulation for 0-45°, and also run another simulation for an almost nude driver like @Juhazi AINOgradients.
But I thought I'd ask if you are spotting any flaw in this, before I spend more time doing those simulation?
But I thought I'd ask if you are spotting any flaw in this, before I spend more time doing those simulation?
https://audioxpress.com/article/tes...bbon-transducer-from-radian-audio-engineering
"Next, I mounted the LM10n ribbon in an enclosure that had a 18”×10” baffle and measured"
Horizontals
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I wouldn't use it below 3-400Hz as dipole in narrow baffle because of distortion. Distortion measurement of Tide is not public...
I really don't understand why Tide has so narrow band for the dipole cone driver and LR4. Using LR2 at 100/400Hz would give lower GD and smoother change from omni to dipole. I have tested many xo versions with AINOs...
"Next, I mounted the LM10n ribbon in an enclosure that had a 18”×10” baffle and measured"
Horizontals
'
I wouldn't use it below 3-400Hz as dipole in narrow baffle because of distortion. Distortion measurement of Tide is not public...
I really don't understand why Tide has so narrow band for the dipole cone driver and LR4. Using LR2 at 100/400Hz would give lower GD and smoother change from omni to dipole. I have tested many xo versions with AINOs...
Here's an attempt to model the Radian LM10n in a Tide-like baffle with Edge, measuring on the tweeter axis, and showing 0, 15, 30, 45 and 60 degrees:
Thank you. Yes, this is the test by Dickason I mentioned on posts #75, 92. I agree it seems best to avoid playing below 300Hz and I wouldn't know why the designer opted to start so lower and not extend the band for the dipole cone.
But totally agree and I plan to xo somewhere between 470Hz (where I cross today and where the natural SLOB rolloff happens) and 600Hz (eyeballing how high SLOB might work). By 470Hz the LM10n seems already in good shape.
Yesterday I was able to listen to Bliesma M142P in OB. An impressive driver in an impressive system. M142P being used as dipole 250 to 1000Hz (2 octaves per Linkwitz), a closed back M74B above it, a T34B as tweeter. AE Dipole 18 as midbass and 4x 24" OB subs behind the listening position. A fully active 4-way system with vinyl as sole front-end. In a purpose-built room, acoustically optimized. Impressive!
What I heard was a temporary set up as the final design will have one M74B facing forward and one facing back to achieve dipole radiation, and same for the tweeter but with T25B facing forward and back.
So what I heard was monopole from 1kHz and up, and dipole below 1kHz. I would have thought this wouldn't sound so good, but it did! I kept walking to the back of the speakers to hear if there was back radiation going that way despite being closed in the back, but there wasn't. Yet at the seating position it sounded so open and airy! Traits I mentally connect with OB designs. This has me revisiting my thoughts and beliefs.
My (living) room was treated before I dove into OB and the front wall (behind the speakers) is absorbent, including bass traps, but also absorbing midrange and up. I do like my current OB mids and tweeters better than when I was doing closed back, even though the back radiation bounces back little. Yesterday's experience has me reconsidering if I do need OB or these Bliesma mids (M142 and M74) would do the trick without the need to radiate as dipole.
So I'm reconsidering M142T or LM10n. The former being much more expensive, an "ultimate" driver for a fair amount of time that allows OB or closed back, that allows crossing lower which is not something I will benefit from. M74 doesn’t like being crossed below 600Hz, from what I read.
Has anybody have a similar experience?
What I heard was a temporary set up as the final design will have one M74B facing forward and one facing back to achieve dipole radiation, and same for the tweeter but with T25B facing forward and back.
So what I heard was monopole from 1kHz and up, and dipole below 1kHz. I would have thought this wouldn't sound so good, but it did! I kept walking to the back of the speakers to hear if there was back radiation going that way despite being closed in the back, but there wasn't. Yet at the seating position it sounded so open and airy! Traits I mentally connect with OB designs. This has me revisiting my thoughts and beliefs.
My (living) room was treated before I dove into OB and the front wall (behind the speakers) is absorbent, including bass traps, but also absorbing midrange and up. I do like my current OB mids and tweeters better than when I was doing closed back, even though the back radiation bounces back little. Yesterday's experience has me reconsidering if I do need OB or these Bliesma mids (M142 and M74) would do the trick without the need to radiate as dipole.
So I'm reconsidering M142T or LM10n. The former being much more expensive, an "ultimate" driver for a fair amount of time that allows OB or closed back, that allows crossing lower which is not something I will benefit from. M74 doesn’t like being crossed below 600Hz, from what I read.
Has anybody have a similar experience?
Yes!
I'm very pleased to hear your experience, which mirrors mine.
I've been working to build a very high performance OB speaker system for a friend with a huge room that exhibits high reverberation. In discussing this project with another DIY speaker builder, who suggested going with a hybrid, with monopole above 1kHz. This would reduce the amount of high frequency energy in the room, reducing the negative effects of reverberation at higher SPL. Specifically, he commented that "the primary benefits of dipole dispersion happens from around 50Hz to maybe 600-1000Hz."
I asked for feedback on this comment in my project thread but got no answers & forged ahead anyway. The reverb reduction made sense, but the idea needed to be tested.
The system I ended up building is a 4-way hybrid OB/monopole, the transition occurring at the 1kHz LR2 XO. Dual SB34SWPL76-4 sub drivers in a Linkwitz W-frame force-cancellation config, XO at 120Hz to OB Satori WO24TX mounted via custom magnet bracket atop the bass box. The high mid + top end is covered by Beryllium domes -- XO at 800~1kHz to Bliesma M74B, XO at 4kHz to Satori TW29B. Flex 8 used for active crossover, a collection of class-D amps to power each driver directly.
The sound is very much as you described, with much of the essential quality of OB. There is a greater sense of immediacy, or intensity, beyond that of my full-on OB LX521 clone. It sounds really good. I consider my buddy's hunch on where the magic of dipole happens is confirmed -- for now. The system is not yet complete and hasn't had the final test at its intended space.
I would also agree with a transition from dipole to monopole in reverberant listening spaces. That's how my open baffles are set up too. Dipole midbass transitioning to partial dipole mid to monopole tweeter.
Thanks for the comments. I know my room is not rverberant, especially at mid/hi frequencies. I would think the carefully treated room I was in yesterday wouldn't be highly reverberant either. But this gives me food for thought.
Of course I will come back to yesterday's room when he has the dipoles ready and I can hear how it's different. In the meantime I'll be revisiting my beliefs!
Of course I will come back to yesterday's room when he has the dipoles ready and I can hear how it's different. In the meantime I'll be revisiting my beliefs!