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Super MWM


Dave A

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Here is the final version which does away with the little pieces to make the full 67.75" width and stays withing the 60" width. It has the 8" section for the woofer and now has a travel of roughly 106". The only other change that may happen is the 15.375" inside height may change to as much as 19" since the wood allows for this and if Claude says the numbers work out. This is the final top view however and I am going to build one by the end of the second week in January so there should be a report soon after. Those of you who have older plans and want the new ones let me know.

 

   This build uses 18mm or .709" Baltic Birch and all dimensions will reflect that. At one time I was thinking of using the 1" equivalent but that started getting heavier fast and these should not need more bulk to resist any resonance anyway being well braced to begin with.

 

final sectional super MWM view.JPG

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5 hours ago, carlthess40 said:

I would like a set of the plans. Please
And would this work with a Klipsch k-45-kt 15” driver ?

When the height is determined I will send you a set. Claude says that Crites better 15" woofer gave the best numbers. I am going to use some K-43-K's I have sitting around that came out of some old John Allen MWM clone bins. My guess would be you could use them but how good they will be here I don't know.

 

  The set of drawings will be rudimentary. Top view of the complete horn with angles and lengths and the a front view of the motorboard with dimensions and between the two there is enough data to build by.

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That is correct it is just as the drawing shows. The reason behind this change is keeping it simple to build and adding little pieces adds complexity. Claude ran the numbers and this did not reduce the lower hz by any appreciable amount. This horn with the last plenum revision now has 106" depth.

 

 

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12 hours ago, Dave A said:

That is correct it is just as the drawing shows. The reason behind this change is keeping it simple to build and adding little pieces adds complexity. Claude ran the numbers and this did not reduce the lower hz by any appreciable amount. This horn with the last plenum revision now has 106" depth.

 

 

This is with a 2 Volt drive for the 4 ohm woofer. The dip at 45 Hz also happens to have the least amount of cone motion, so it can be PEQ'd if you wish. The black is the 19 1/2" 5x5' Baltic Birch "rip cut" for all the internal parts, so all the lumber is 5x5 to start. Since this uses a single 15" driver, making this 21" tall rather than 17 give the Black curve vs. the gray one, both with the Crites 1526C. No subwoofer will be required for music. The ripples in the response get totally overwhelmed by the room acoustics, so it's not important. Having the horn taller give about 2 Hz. more low end extention, but more importantly, the extra bass between 60-100 Hz.

 

SuperMWM19crites1526c.jpg

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With the final design now done I have included all the bracing and stuff just like I intend to build it for myself. Here is the deal on the details. I can provide anyone with a 3D CAD assembly file if you have a good CAD program to open it up with. This is available right now just tell me what format you need it in. Comprehensive 2d line drawings are not going to happen real quick since I don't need them to build by. So unless someone can convince me they are dead serious about building a set like right now it may be a month or two before I sit down and do this set of 2d drawings.

final screen capture.JPG

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39 minutes ago, carlthess40 said:

Heck. I think with all the info in the pics I can build one
I have some 15” and some 12” drivers I could use. These are for a 15” ? What t/s numbers should I look for in a driver for this box ?
Great work as always

That's right all the real info is there. Laying out the top piece by these measurements will give you all the angle and lengths of the parts required for sides and braces and the dimensions on the plenum provide all you need for that. The biggest reason I am not in a hurry to make a set of drawings is that they are not really needed to build by. What is missing is the 19.5" tall motorboard which I will post later today. This is pretty simple to build other than the size.

 

 Claude has made recommendations and he is the numbers guy in this. While this is my idea he is the one who tells me right or wrong. You will have to ask him about this and I would say for sure using 12" is a no no without any doubt. If you are considering building this and putting the time and money into it I would at the very least use something designed for it. K-43, K-33 or Crites woofers are all I would consider at this time. There may be a better one out there but I am not looking.

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On 12/12/2018 at 8:51 AM, Mrscy said:

Thank very much, please assist with hornresp input data, i have 2 Beyma 15G450 and a DAS15G , I want to simulate.

Here's your sim for the Beyma 15G450 vs. the Crites 1526C in gray for reference. Keep in mind that it's an 8 ohm woofer vs. a 4 ohm woofer, so I simulated the Crites with a 2 volt drive (for about 1 Watt) vs. a 2.83 volt drive on Beyma (for about 1 watt). Both of their responses fit within a +/-2.5 db variation within the horn, but if you study the curves, the Beyma has a slightly higher cutoff, but with more output in the sub 45 Hz. region, all of which will be overwhelmed by ROOM Acoustics!! None of the woofers will need more than 20 watts of peak power to reach above 120 db output. More than likely, "normal" levels will be in the 1/16th watt range.

SuperMWM19beyma.jpg

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On 12/13/2018 at 11:39 AM, Khornukopia said:

 

So there is NO horn flare for the last 13" of the cabinet?

Correct. As a Jubilee owner, one can see a final "splay" in that bass horn, which improves the high frequency section by moving the two half-mouths closer together. According to Chief Bonehead, that was the trick that allowed the Jube bin to cross over at 800 Hz. for PWK's 2 way version with the small horn on top (something I saw for myself at Valerie Klipsch's house in 2007. 

 

BTW, the woofer driver's rear chamber cover dimension will end up at 17" Wide X 19.5" H tall, as the width of the core section will remain 15.5 inches wide internally and 17" wide as a result of the 3/4 inch thick plywood inside the bin.

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Just a note on the bin wood. This design is using 18mm Baltic Birch and 18mm = .709" and the tolerance specs are +.7mm -.9mm or .673mm to .736mm. The corner braces I suggest are 1" x 1". I am probably going to get one sheet of 25mm birch for the motorboards and corner braces.

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On 6/19/2018 at 10:45 PM, ClaudeJ1 said:

Well, you were not privy do Dave's evolution back to me. He did the plans, and I did the sim, so it was a bit of back and forth once he figured out how to splice two pieces of lumber together as to NOT shrink the mouth down to 60 inches wide. So I agree with your assessment of my V3 mod. here, skipping a few in-betweens. When you can get flat to almost 30 Hz. only HT requires a sub, and I definitely am a fan of a 300 Hz. horn and 3 way for the mids, just like you.

 

I also pulled a Dubyah by "misunderestimating" the last calculations. Here's the new one.

The Maximum woofer excursion is only 1.4 mm, which is what PWK measured in the Khorn while it was at full output. So the K33 only moves 1/16th of an inch while putting out 30 Hz. at 115 db while doing 105 db at 25 Hz. using only 2 Watts while the horn is in a corner. Subwoofers you say? NAH. However, a good high pass filter is highly recommended for those who would use a 100 Wat amp with this very sensitive horn.

Now to find a 300 Hz. midrange horn (I actually own 10 drivers and 2 horns that will do 300 Hz, so may the best one win!!).

SuperMWMv3.1.jpg

 

Which 10" DIY-able mid-range horn would you recommend?

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14 minutes ago, jwc said:

How deep is this thing?

 

Is this 60 x 60 x 17?

60 x 60 x 21. Initially I fogot to add the extra volume of air in the sides of the core section. This yields less of a dip between 45-70 Hz. Black is K43, gray is Crites 1526C.

 

SuperMWMK43vsCrites1526C.jpg

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