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Super MWM


Dave A

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5 hours ago, mark1101 said:

 

I didn't try..........I actually sold them.  The 305s.

 

Why...........because I replaced them with a set of used JWC XII modules.  

Ah, new, improved. Way to go. Or should I have said, older, not improved. LOL. 12" instead of 8" driver, right??

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The XIIs are 12" and 305s were 8".  The 305s were 402 horns so good for polars.  The XII are something different, maybe modified tractrix.  But in my room I doubt I can even get 10 degrees off axis with those monsters in there.  The XIIs needed no EQ.  The 305s had a nasty peek that needed EQ.  The XIIs just sounded better to me.  Yes, they are the older speakers.  I kept the ones that sounded best.

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@jwc    I'm trying to get those MWM bins from the college. We'll see how it goes... I think they just have them stored, which is shameful.

 

I'll just about give away the LS if I can get them.

 

Bruce

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I did stop in today to see the mechanic and the forklift is done and the roll back scheduled for Tuesday to get it here. Don't worry when things happen I will document it all. I am suffering from audio withdrawal right now and my eyes twitch and I keep seeing nothing where the MCM 1900's used to be when I look straight on at the empty spot. I look away and I could swear I see them out of the corner of my eye's. It's bad when you have hearhalucinations at the same time.

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Rayyyy the forklift made it back this afternoon.  So work commences on these. Before I start though I thought I would upload the last design iteration and explain some things. Please note the brown colored pieces.These will serve two functions. One will be as a guide and brace for the inner plenum side walls. The other will be as a reinforcement to the back side of the TEE nuts used to hold the speaker in place so they cant be forced out by accident. Once this is assembled there is no way to get to the TEE nuts outside of some destructive means and this should end any possibility for trouble.

 

860667050_detailofmotorboardbackside.JPG.c048ab701f9df25b0ecec5b9112df3ac.JPG

 

Now for the top view. The two brown pieces are referenced above and you can see them in the assembly as guides for construction and strength. Green pieces are the 1" x 1" corner braces and the item of interest here are the two yellow pieces. This is a change and it does away with that silly little beveled piece I first had and uses instead an end cap to tie the two inner and outer plenum ends together. I have also attached a .step file for those of you (Marvel) who have access to design software. As time passes and I have the first build under my belt I will make time to do some 2D files for those of you who can't deal with 3D files.

 Sides and top are 1" (25mm) Baltic and the plenum is 18mm or .709" thick theoretical width.

 

  This initial build will have a removable back for the purposes of testing deflectors opposite from the plenum mouth similar to the ones in the La Scala. It will be screwed on and sealed with foam tape until I am happy with it. Also this is a darned big horn so the removable back will allow me to Duratex it all inside and out after construction and the back can all be screwed and glued to the box when I am done tinkering. I will start initially without the deflector and if it sounds and tests good enough I wont bother with deflectors. The MWM apparently did not need them so my guess is these won't either but better safe than sorry.

 

 

 

 

779465779_topviewfinalsupermwmbin.thumb.JPG.2464964b36c62b6fee36d57cffc03765.JPG

final design for production super single mwm bin.stp

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3 hours ago, Dave A said:

Once this is assembled there is no way to get to the TEE nuts outside of some destructive means and this should end any possibility for trouble

 

Until you cross-thread one and run the screw in with a power driver...

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6 hours ago, glens said:

 

Until you cross-thread one and run the screw in with a power driver...

A prudent thing to do is to run a tap through the Tee nut and make sure the threads are clean before speaker install. Another would be to hand start the screw to make sure it is not going in cross threaded.

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11 hours ago, Dave A said:

I will start initially without the deflector and if it sounds and tests good enough I wont bother with deflectors. The MWM apparently did not need them so my guess is these won't either but better safe than sorry.

 

When I spoke to former Klipsch Chief Engineer, Gary Gillum, about 12 years ago, he said that a "splitter" after the first core section didn't make any difference. However, since this is NOT a LaScala, Khorn, or Jubilee, it's a really LONG horn, so if you are trying to get to 400-500 Hz. crossover, it will need all the help it can get. Different is not the same (as a Klipsch MWM), so I would not theorize about it. You need to build one and measure. Safer than sorrier, indeed.

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10 hours ago, Marvel said:

Very cool! I personally don't think you will need the reflectors for the low frequencies/long wavelengths involved. Looking forward to seeing pics  of the build.

 

Bruce

And what specific FREQUENCY are you "personally" thinking of when you make that statement??

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57 minutes ago, ClaudeJ1 said:

When I spoke to former Klipsch Chief Engineer, Gary Gillum, about 12 years ago, he said that a "splitter" after the first core section didn't make any difference. However, since this is NOT a LaScala, Khorn, or Jubilee, it's a really LONG horn, so if you are trying to get to 400-500 Hz. crossover, it will need all the help it can get. Different is not the same (as a Klipsch MWM), so I would not theorize about it. You need to build one and measure. Safer than sorrier, indeed.

 

I am making allowances for this Claude and will try it. I just want to get a basic horn done though and these experiments with splitters are second in line. Once we determine what works best I will preserve the build info for others and zip the back panel up for good.

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15 hours ago, glens said:

 

Until you cross-thread one and run the screw in with a power driver...

 

8 hours ago, Dave A said:

A prudent thing to do is to run a tap through the Tee nut and make sure the threads are clean before speaker install. Another would be to hand start the screw to make sure it is not going in cross threaded.

Yes a good idea, but being you can not get to them I added a piece of wood screwed down with a hole drilled in it for the bolt, to make sure it couldn't push back out. I screwed and glued the tops and everything together so there was no getting to it later, which is what scared me.  

mwm (23).JPG

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26 minutes ago, dtel said:

 

Yes a good idea, but being you can not get to them I added a piece of wood screwed down with a hole drilled in it for the bolt, to make sure it couldn't push back out. I screwed and glued the tops and everything together so there was no getting to it later, which is what scared me.  

mwm (23).JPG

See the above drawings as this is what I did.

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OK I see it now, I was looking at that earlier and was not sure what I was looking at. :emotion-21:

 

All I could think about was what if I pushed out some t nuts when putting in the driver, I would be in trouble. Klipsch used t nuts that had 2 ears on them which got screwed in, I couldn't find anything like that. 

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