AudioCircle
Industry Circles => GR Research => Topic started by: Optimizer on 31 Jan 2021, 07:07 pm
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Hey quys,
I have created 3D vizualistion of NX-Otica MTM with recteangle base.
My goal was to keep all accoustic igneneering as was deveopped and to shrnik space requierements as much as possible.
All dimensions and angles during drawing was estimated.
Only two changes was made:
1) modified shape of the bottom plate
2) modified short wing - cut from the outside
This is what it would look like:
(https://www.audiocircle.com/image.php?id=220315)
(https://www.audiocircle.com/image.php?id=220318)
(https://www.audiocircle.com/image.php?id=220316)
(https://www.audiocircle.com/image.php?id=220317)
(https://www.audiocircle.com/image.php?id=220319)
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The only way do that is if you affix the speaker onto a separate rectangular base. But why???
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It is more practical and it saves the space. Wedge base don't fits at no stand. Last but no least, all furniture is square.
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It is more practical and it saves the space. Wedge base don't fits at no stand. Last but no least, all furniture is square.
The NX-Otica MTM is designed to sit on top of a pair of OB servo subs. It's too wide for speaker stands. There's plenty of reasons why Danny angled the wings. Any attempt to turn these speakers into a rectangle would require a crossover re-design.
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Danny explains exactly why they are angled the way they are in this video.
https://youtu.be/7ipMq7KlWwM
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I think everyone seems to be missing the reality that the ~10° wing offset is still present in the render. But instead, the front baffle is angled off-square compared to the rest of the base, and the inside of the smaller wings are also still angled correctly.
And so long as the edges of the baffle are rounded over, I could see this actually working, but only for the MTM model.
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But instead, the front baffle is angled off-square compared to the rest of the base, and the inside of the smaller wings are also still angled correctly.
My friend's NX-Otica MTM's have a straight front baffle and the base is an isosceles trapezoid. They have the footprint of a floorstander.
(https://www.audiocircle.com/image.php?id=220339)
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Hey quys,
I have created 3D vizualistion of NX-Otica MTM with recteangle base.
My goal was to keep all accoustic igneneering as was deveopped and to shrnik space requierements as much as possible.
All dimensions and angles during drawing was estimated.
Only two changes was made:
1) modified shape of the bottom plate
2) modified short wing - cut from the outside
This is what it would look like:
(https://www.audiocircle.com/image.php?id=220315)
(https://www.audiocircle.com/image.php?id=220318)
(https://www.audiocircle.com/image.php?id=220316)
(https://www.audiocircle.com/image.php?id=220317)
(https://www.audiocircle.com/image.php?id=220319)
Very cool - I like it!
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This looks cool, I used to own the MTMs and the trapezoid base was slightly aesthetically annoying given that it sat on a square subwoofer box. I think the long edge on the short wing will be sharper in reality than the render presents though and might be prone to damage from incidental bumps during a build. Maybe a bevel towards the outside edge of the short wing would help.
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So long as the angle and size of the side wings are kept then you can do just about anything you want with the interior base.
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Yes the ~10° wing offset is still present and size of wings are the same.
This soulution would be accepted by wide range of potential buyers including me. I vote for it.
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I like where your head is at on this, but unless I'm missing something you've now got a geometry problem on the short wing side.
Angling the front baffle in the direction you have puts the long wing in the right spot in terms of angle compared to the reference design. The problem this creates is that you have actually angled the short wing IN ten degrees instead of OUT ten degrees by squaring it off.
Danny posted above that you can do whatever you want on the inside (which it looks like you've put a ten degree angle on the short wing on the inside to match the reference design), but again your problem is on the outside (the side that matters).
One maybe easy solution would be (because the short wing is so short) just send the base shape out that ten degrees only as far back as the short wing goes, then chop the base square to the back the rest of the way. You'd still end up with a more rectangular base that should fit better on a stand (or arguably look better on an OB woofer section that is rectangular rather than trapezoidal in shape). Sure, your front baffle will inherently has some toe-in, but the rest of the box will look relatively 'normal'.
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I do not think so. The short wing is ten degrees OUT as it should be. Look at it from inner perspective.
It is possible that my design has some issues which are not obvious now.
Unfortunately I don't have dimensions and angles of original NX-Otica MTM, so I can't render it with high precision.
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If it helps, the front baffle is 1.5" thick & 8.5" wide, the long wing is 14" long, and if i remember correctly, the short wing is 1" deep at the tweeter & 2" deep at the woofers. With 10° offsets on both sides.
The only dimension I dont actually know is the height. Danny or Captainhemo or Mike Lundy would have to comment.
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The original prototype cabs for the NX-Otica MTM were similar to what you describe (base flush with sides). The difference is that the base on the short wing side followed the line of the short wing angle. If the base was cut straight back at the end of the short wing (parallel with the long wing) it would be what you drew up.
(https://www.audiocircle.com/image.php?id=220587)
(https://www.audiocircle.com/image.php?id=220588)
Mike
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Yes it is exactly what I did. I went a little bit further and cut a piece of the short wing from the outside.
To achieve rectangle shape of the base it is needed to cut a new shape due to missing part - see picture.
(https://www.audiocircle.com/image.php?id=220590)
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Hey guys -- you're looking at this all wrong. Build a wider base to accommodate a premium crossover. 8)
Here's an example of why you need more room back there (12" wing):
(https://www.audiocircle.com/image.php?id=220591)
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I see, you need the rectangle base! One thing is missing. A padlock on the treasure chest. :D
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I see, you need the rectangle base!
My speakers already have a rectangular base. The wings aren't resting on the base.
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Yes it is exactly what I did. I went a little bit further and cut a piece of the short wing from the outside.
To achieve rectangle shape of the base it is needed to cut a new shape due to missing part - see picture.
That missing part shown in the picture is exactly your problem. Look at the original trapezoidal shape of the reference cabinets. Note that both wings (long and short) angle out - away from the baffle - on the outside face by whatever the angle (you note ten degrees). What Danny explained above is that your change on the inside area of the base (behind the baffle) is what can change (within reason) without any problem. Because you removed the angle from the outside of the wing, you've effectively changed the angle of the wing relative to the front baffle. This is what will cause you a problem.
Danny's reference design widens the front baffle on both sides with the wings; your change widens the baffle on the long wing side only. The part you cut off of the short wing is the critical part to the design of the wing. I hope that makes clearer what I posted earlier?
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On the next picture below you can see that I did not changed trapezoid configuration. Both wings are opened cca 10 degrees out. Hence it should be OK.
(https://www.audiocircle.com/image.php?id=220594)
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It's very clever :thumb:
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Not sure how strudy the short wing would be beveled like that nor how the pointed edge would behave. You’d have to mock up a speaker and send it to Danny for testing like I did with the prototype I posted pics of
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Not sure how strudy the short wing would be beveled like that nor how the pointed edge would behave. You’d have to mock up a speaker and send it to Danny for testing like I did with the prototype I posted pics of
Yeah, even a very slight modification requires going back to the bench.
Besides, there's no real world benefit to rectangulate the base. Sure, you shave off a couple of square inches, but that's insignificant. This speaker is huge in real life. It's still gonna be at least 14" deep and angled no matter what you do.
Expand your options. Consider a metal base. This can be improved upon, but it's thinner and sturdier than MDF, looks badass, and allows for all sorts of footers.
(https://www.audiocircle.com/image.php?id=220596)
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On the next picture below you can see that I did not changed trapezoid configuration. Both wings are opened cca 10 degrees out. Hence it should be OK.
(https://www.audiocircle.com/image.php?id=220594)
I'll try one more time before bowing out. See the lines on the short wing (right) side of this picture that outline the space missing from the original wing (the white lines marking the black void space beside the angled cut/modeled wing)? The outermost line - which would be the outside face of the wing in the reference designed cabinet - is the critical part. By removing it, you have changed the angle of the outside face of the short wing and folded it behind the front baffle instead of having it extend away from the front baffle by ten degrees.
I know to get what you're after you want that angle gone, but it is a (the most) critical part of the wing design. Sure, your wing makes the baffle's effective width the same as if the angle was ten degrees out as per the reference design (the clever part) but the angle is wrong - ten degrees the wrong way. I'm sure if the speaker could have been optimally designed with squared off wings to produce the response Danny was after, he would have just left them squared off (because it would make cabinet assembly and manufacture much easier), but bottom line is that everything matters, how the sound wraps around the cabinet matters, and it may be small but your design will change that. I'm not saying it won't work; it just won't end up as intended.
Not sure how strudy the short wing would be beveled like that nor how the pointed edge would behave. You’d have to mock up a speaker and send it to Danny for testing like I did with the prototype I posted pics of
This is really the best answer, and the only way to make sure you end up with a final product that meets the performance of the design as-is. If Danny hasn't tried it out already to know whether it would be fine or not (or what if any crossover changes are needed or not to make it work), I'm sure he'd be glad to measure a test cabinet you build out and send him to check it out. We're all here just trying to help out to make sure you get a great sounding speaker and end up with a speaker you'll like. :thumb:
Good luck!
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It's the OUTSIDE of the wing that makes the difference? I would have assumed it was only the inside, but that does make some sense if you think about the separation of the front wave and the back wave.
If true, just keep the short wing thickness throughout and square up the base to the outside edge of it....don't square up to the front of the baffle but to the back of the wing. That only makes the base slightly wider, but you have the full short wing then.
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Thank you!!! I thought I was :banghead: failing at explaining it!
From what Danny has shown (search prior threads where folks discuss the wings on OB speakers) here, both sides matter, but in different ways. Check out the design thread for the NX-Otica to see how the design process evolved to the shape the final cabinet was made, which similarly will apply to this MTM version. It doesn't seem like such a small angle should matter much for such a small wing on such a small baffle, but as has been said many times before, everything matters.
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Danny mentioned size of the wings, not their thickness. But you are right. Some wave lengths may be affected - cancelled.
But which and how much? Can't say. I don't know. But I am pretty sure that with some modification of the short wing it will work.
The only way to reveal potential issues is to do some measurements.
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Danny mentioned size of the wings, not their thickness. But you are right. Some wave lengths may be affected - cancelled.
But which and how much? Can't say. I don't know. But I am pretty sure that with some modification of the short wing it will work.
The only way to reveal potential issues is to do some measurements.
It isn't the thickness of the wing that's the concern; it is the geometry. As long as you end up with the same outside dimensions and geometry of the reference design while maintaining enough rigidity/structural strength that the box doesn't fall or rattle apart, you'd still be good to go.
Take the X-Otica design for example (very similar to this one but using a dome tweeter instead of the neo-3, just to ignore the needed depth for the tweeter wave guide for sake of example). You could bend a sheet of, say, 1/8" plate steel or aluminum and end up with a working baffle so long as you bent it in the same trapezoidal shape with the same outside dimensions (maintaining the geometry, reducing the thickness).
It isn't a matter of revealing potential issues at this point, that there will be issues is a given; a test cabinet and measurements will determine what Danny has to do to the crossover to get as close to the reference design as possible and what if any performance compromises are made in the end result regardless of what has to change. Check out this thread where Danny discusses baffles and follow the link he posts to the thread discussing the Wedgie. I think it very clearly shows what you're up against here:
https://www.audiocircle.com/index.php?topic=160242.0 (https://www.audiocircle.com/index.php?topic=160242.0)
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Everything matters but some things goes beyond my imagination. Short wing is there to avoid cavity resonance. It is also importat to separate the front wave from the back wave. All aspects Danny mentioned. He developed design that works well.
I don't want change anything about that. My only intention was to change base shape and that's it. If someone do some measurements and say that there is a big problem with this design I will accept it easely. Now I don't see unsolvable problem here.
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I posted this a long times ago in another thread .... from ouir original design of these:
(https://www.audiocircle.com/image.php?id=136151)
.You can make the base square if you want ( just transfer the dowel/screw pattern from orignal base to a rectangle base) or, cut as Mike suggested.
In either case, you won't get the wedged wings parallel with a square/rectanular base... if you did, it wouldn't be a wedge anymore :)
jay
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Sorry to necro an old thread, but... do I remember correctly that the long side baffle is 20" deep and the other was about 4"?
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Sorry to necro an old thread, but... do I remember correctly that the long side baffle is 20" deep and the other was about 4"?
The long side is 14 inches long (past the back face of the baffle) while the short side varies.
Around the mids, they are 2" long at the mids and flush at the tweeter. for the Otica/Xtreme they are 14" deep at the bass drivers.