Impertinent half serious question...

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aceinc

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Impertinent half serious question...
« on: 4 Feb 2017, 04:58 am »
In obsessing about my next DIY project, I like the idea of an OB/dipole system. Being a penurious fellow, I don't want to spend a penny more than I must. Being an IT person I am used to "mashups."

Phase 1, buy a pair of GR-Research OB 12" woofers kits, build the W frames. Double side wall which should make the cabinet 14.5" wide.

Phase 2, buy a pair of Magnepan MMG speakers.

Phase 3, strip the base off the MMGs and build sturdy, yet attractive, mounting assembly for either the entire MMG, or just the panel/xover assembly (stripping the sides off).

Another option would be to build either the H or W cabinet and lay it sideways, and mount the MMG on top.

The impertinent question, how would this sound in comparison to the same Woofer (sub if you prefer) assembly with the NX-Otica?

It would save $300.

I am looking for insight here so all comments are welcome (even derisive laughter), What do y'all think?

ebag4

Re: Impertinent half serious question...
« Reply #1 on: 4 Feb 2017, 05:04 am »
I can't help with the comparisons but the first thing that sprang to mind is that the amplification requirements for those speakers are completely different.  What type of amplification are you using?

Best,
Ed

aceinc

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Re: Impertinent half serious question...
« Reply #2 on: 4 Feb 2017, 05:13 am »
Emotiva XPA-1s Gen 1, but the Woofers would be driven by the servo amps.

mlundy57

Re: Impertinent half serious question...
« Reply #3 on: 4 Feb 2017, 06:20 am »
I haven't heard the MMG's but Joemamma had a pair that Danny redid the crossovers for. Joemamma then got a pair of Wedgies which he has paired with dual 12" OB subs. He kept the Wedgies and sold the Maggies.

As I said, I haven't heard the MMGs but I do have the Wedgies and the NX-Otica MTMs, both paired with dual 12" OB subs. The Wedgies and Oticas are both exceptional speakers. There are differences but I haven't decided which one I like better. They are both that good.

That's a roundabout way explaining why I would say go for the Oticas. You won't be disappointed.

Mike

bdp24

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Re: Impertinent half serious question...
« Reply #4 on: 4 Feb 2017, 03:38 pm »
In obsessing about my next DIY project, I like the idea of an OB/dipole system. Being a penurious fellow, I don't want to spend a penny more than I must. Being an IT person I am used to "mashups."

Phase 1, buy a pair of GR-Research OB 12" woofers kits, build the W frames. Double side wall which should make the cabinet 14.5" wide.

Phase 2, buy a pair of Magnepan MMG speakers.

Phase 3, strip the base off the MMGs and build sturdy, yet attractive, mounting assembly for either the entire MMG, or just the panel/xover assembly (stripping the sides off)

Another option would be to build either the H or W cabinet and lay it sideways, and mount the MMG on top.

The impertinent question, how would this sound in comparison to the same Woofer (sub if you prefer) assembly with the NX-Otica?

It would save $300.

I am looking for insight here so all comments are welcome (even derisive laughter), What do y'all think?

I haven't heard the NX-Otica, so can't comment on it vs. the MMG. It you decide on the MMG, however, your idea of laying a pair of OB subs on their sides and using them as stands is an interesting one (I do the same with my QUAD ESL's). The MMG benefits from being raised off the floor anyway (doing so raises the image height---the MMG is rather short for a planar speaker), and the 15" width of the double-wall W-frame (13-1/2" stock, plus 1-1/2" for two more layers of 3/4" MDF) is perfect. Danny recommends against putting speakers on top of subs (because of the sub enclosure vibrations being transferred into the speakers), but what does he know ;-)? You can isolate the speakers from the sub frames with the remarkable Townshend Audio Seismic Pods, a very sophisticated design. Not cheap, but very effective. A more economical alternative is a set of roller bearings under each speaker.

By the way, love your use of the words impertinent and penurious. A good vocabulary is a rare thing these days, what with the state of education in the good ol' U.S.A. Ya'll finished High School, didn't ya?!

aceinc

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Re: Impertinent half serious question...
« Reply #5 on: 4 Feb 2017, 04:44 pm »
No comment on my education. It would surprise too many folks.

As I ruminated some more I believe that making a stand for the MMGs the depth of the woofer enclosure having a base that the woofer amp could mount on might be a good choice. This would allow the MMG to stand perpendicular to the floor (upright), with the amp providing counter balance. It would change the sound of the MMG (slightly I think) as it would increase the distance the front wave would need to go to meet the rear wave.

Here is a rough drawing of the concept.




nickd

Re: Impertinent half serious question...
« Reply #6 on: 4 Feb 2017, 04:48 pm »
I owned mmg's a few years back and enjoyed the transparency. Danny's designs are WAY more dynamic in the bass, mid bass and lower mids. You will end up selling the Maggie's if rock and dynamics are in your musical wheelhouse.

bdp24

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Re: Impertinent half serious question...
« Reply #7 on: 4 Feb 2017, 05:48 pm »
No comment on my education. It would surprise too many folks.

As I ruminated some more I believe that making a stand for the MMGs the depth of the woofer enclosure having a base that the woofer amp could mount on might be a good choice. This would allow the MMG to stand perpendicular to the floor (upright), with the amp providing counter balance. It would change the sound of the MMG (slightly I think) as it would increase the distance the front wave would need to go to meet the rear wave.

Here is a rough drawing of the concept





The front wave and rear wave meet and cancel on either side of the MMG panel. Raising it will in no way change that, but the sound will be changed for other reasons, one being the panel will no longer be loaded by the floor.

aceinc

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Re: Impertinent half serious question...
« Reply #8 on: 4 Feb 2017, 06:01 pm »
Raising it doesn't, but adding the sides as I drew them would. The lower part of the stand would, as I understand it, create a resonant chamber whose frequency would be determined by its dimensions as well. If the resonant chamber was deleterious to the SQ, Large-ish holes could be cut into the side to alleviate that.

bdp24

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Re: Impertinent half serious question...
« Reply #9 on: 4 Feb 2017, 06:09 pm »
Raising it doesn't, but adding the sides as I drew them would. The lower part of the stand would, as I understand it, create a resonant chamber whose frequency would be determined by its dimensions as well. If the resonant chamber was deleterious to the SQ, Large-ish holes could be cut into the side to alleviate that.

I don't see any mention or drawing of added sides. Is it on another thread?

aceinc

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Re: Impertinent half serious question...
« Reply #10 on: 4 Feb 2017, 06:14 pm »
nickd, I listen to various styles of music, including rock. These speakers would also be used for HT. The speakers I currently have, (Either KEF 105.4, or B&W 802 Matrix, right now I am using the the B&Ws) sound pretty good, but they don't have my fingerprint on them.

My center channel which I designed and built myself and could certainly use Danny's xover treatment (if he wouldn't laugh at it) has my fingerprint on it as do my Subs which include a Rythmik Audio DS1500 and my rear channel speakers.

Having never heard Maggies, I would rely on people that have, such as yourself, to describe in a way that makes sense to me what you mean by more dynamic. Towards that end, could you give me some examples of songs/music that sound better, and what you noticed?


aceinc

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Re: Impertinent half serious question...
« Reply #11 on: 4 Feb 2017, 06:25 pm »
Here is another (enhanced) picture.



Keithh

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Re: Impertinent half serious question...
« Reply #12 on: 4 Feb 2017, 07:44 pm »
I currently have both the Wedgies and MMGs and have owned the B&W Matrix 802, which I sold a while ago. Both the MMGs and 802s are good speakers, but
the Wedgies and NX-Oticas are in a completely different class. I don't know if you have heard an OB system, but everyone that has listened to the Wedgies has thought it was by far the
best speaker they had ever heard. It is hard for me to listen to conventional speakers like the 802s after hearing an OB speaker.
The MMGs compete with $1K speakers but for only $300 more you can get the NX-Oticas which compete with the best speakers made that often cost as much as new cars.

Having heard both the Wedgies and MMGs, for me it would be quick and easy decision which to choose.

bdp24

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Re: Impertinent half serious question...
« Reply #13 on: 4 Feb 2017, 09:09 pm »
Here is another (enhanced) picture.



Ah, I see. I believe the sides would need to come all the way to the top of the MMG's to prevent front-to-back cancellation. And I think any holes drilled in those sides would allow cancellation as well, though I may be mistaken. Best ask Danny. But if the speakers and subs are for HT use, I wouldn't consider the MMG the best choice.

mlundy57

Re: Impertinent half serious question...
« Reply #14 on: 4 Feb 2017, 09:42 pm »
A caution learned the hard way and after multiple phone calls to Brian at Rythmik: For the LFE (Sub Out, .1/.2) channel for HT you will need a sub(s) designed for HT use (sealed or ported). OB subs are designed for normal frequencies down to 20Hz. Do not connect an OB sub to the LFE/Sub Out connection on an AVR or Pre/Pro (or set "Subwoofer" to "none"). The high intensity infasonic (below 20Hz) frequencies (sound effects) found in the LFE track of movies (especially action movies) will cause the OB drivers to bottom out.




aceinc

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Re: Impertinent half serious question...
« Reply #15 on: 4 Feb 2017, 09:50 pm »
Regarding using the speakers for HT, I think of this concept as a single full range speaker, which is why I keep referring to the 12" subsystem as the woofer section.

I can and would leave the existing subs in my system for HT use. These speakers would be treated as "full range" speakers by the sound processor, and would NOT have the Sub out from the processor plugged into these, I'm hoping to get 108 DB at 1 meter from each speaker 20hz-20khz, total 111 DB for the two combined. Should be able to get 102 DB at the listening position, if I am so inclined, which should be adequate for most HT. At least for me.

aceinc

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Re: Impertinent half serious question...
« Reply #16 on: 4 Feb 2017, 09:56 pm »
My thought on the woofer section of this speaker would be a narrow range say below 100 hz. I know that the subsystem is rated above that, but I have a concern about doppler distortion. Were I to ask these little buggers to go real low, and into the low midrange I could envision problems. Without having seen it, I can imagine there is a lot of excursion as the woofers try to push the air about at low frequencies.

mlundy57

Re: Impertinent half serious question...
« Reply #17 on: 4 Feb 2017, 10:09 pm »
Yep, that's exactly the way to think of them, as two part full range speakers with the midrange/tweeter passive and the bass active.

With the NX-Otica MTM's I cross to the bass section @ 100Hz (the Wedgies cross @ 200Hz).

Shakeydeal

Re: Impertinent half serious question...
« Reply #18 on: 5 Feb 2017, 12:21 pm »
I agree with some of the comments about the MMG. A friend of mine had a pair for a while, and I have owned 1.6s and 3.5rs. While the transparency and openness are addictive, maggies do have their drawbacks. An OB design with Danny's subs will give you the best of both worlds. I have Super Vs and they are as open and transparent as maggies but move way more air in the mid bass and pressurize the room like a planar cannot do.

I'm sure this will be a nice enhancement to the MMGs, but it won't fully replicate what an OB design will do.

Shakey

THROWBACK

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Re: Impertinent half serious question...
« Reply #19 on: 5 Feb 2017, 01:30 pm »
Sort of depends on the room. A friend of mine has an MMG-based system (supplemented by a single DIY woofer) in a very small room and it sounds wonderful. The Super V's are terrific, but would they sound as good in my friend's room? I dunno.