Experiments with M2 horns.

[srm51555]

I'm trying to visualize M2 components in a 4365 sized box here.


Edit: Getting fussy with the drawing.

Great to see your getting started on your project. The original M2 cabinets are quite large in height so they might not fit well with a living room decore, I would be hesitant with them and the kids in mine but they do raise the 2216nd off the floor nicely.

keep us posted,
Scott

[Don C]

I started wondering about the size. So I did some CAD (cardboard assisted design) work and mocked up the cabinet. It was too big for my room. And probably too big for me to ever move. I have never seen 4365s in person, and so I didn't know how huge those are. They are huge. So I've redesigned my cabinets smaller.

[DES-1]

I started wondering about the size...

Be careful, there must be a point where reduced volume and baffle size will begin to cripple performance, despite flexible tuning of dsp. I've been thinking along the lines of a 4367 enclosure but it is nearly as huge, roughly 37x22x17.

[Don C]

I'm looking at:
38in x 21in x 13 in for 4.35CF.
So it's still pretty big.

[bubbleboy76]

I have never seen 4365s in person, and so I didn't know how huge those are. They are huge.

My wife could have told you that! She almost had a heart attack when we got ours

[ivica]

http://sound.whsites.net/articles/ntm-xover.htm

Hi zeljkor,

Very interesting link, and thank You it.
I wonder what would be the differences betwenn NTM and "standard" LR crossover (say 4th order) from the listener point of view, not to mention its complexity (including additional noise and distortion "contributions " in the signal path, if realized in analog domain ).

I want to emphasize here that even " brick wall " filters are not so "wellcome " as audio crossover filter in the multi way' speaker system when the driver are appart each the others.

Mybe here in M2 solution sharp LF cutoff is a must to protect D2430K driver diphragm from the "over- excursion " at lowe frequency, as M2 horn loading under say 1kHz is not so perfect.

Regards
Ivica

[ivica]

.....I did some CAD (cardboard assisted design) work ......

HI DON C,

What a nice definition!

But in order to get sound monitor bass response small box is not appropriate solution.
Electronic LF EQ can be applied on many other solutions, but its sound is far from being compared with the "natural" driver response.It would be nice if we can get pancake like bass box solution, preferably postcard size, so can be hanged on the wall.

I do not want to mention here some military developed ultra LF very narrow bass-band
DSP controlled multi elements array solution, that can deliver over 140dB sound levels.
I have no idea about THD and FR response in the pass band of such sound sources.
http://www.explainthatstuff.com/directional-loudspeakers.html
https://www.google.com/patents/us7343017



Ivica

[Don C]

The box dimensions are set now. But I think that a grille cloth is badly needed. And there is still a decision left to make about the style and color. I'm leaning towards two tone, because three feet of plain black seems like a lot.

[pos]

Are you going to raise them on feet?
The center of the woofer is around 60cm off the floor in the original design.

[sebackman]

Some inspiration.

[Don C]

I certainly will experiment with placement and height. For some reason the existing le14h-3 woofer sounds great, even though it and its vents are right down next to the floor.

[Don C]

My wife gets a vote, and in this case I think it's the deciding one. For this:

[Don C]

It's about time to be converting ideas into cabinets. This is going to lack some of the precision that we've seen on some other recent projects. I'd like to call this a garage project, but my garage is too full of other stuff, so I have to wait for nice days and work in the driveway. I started with 3 sheets of 1 inch mdf. Special order. Because the full sheets are too large and heavy to manage, I asked the lumber yard to cut each sheet into four equal sized pieces, much easier to deal with. They do this with a big panel saw, but unfortunately, that saw doesn't cut square.
I don't have pictures of the cutting, but I took the sheets to a friend's house because he has much nicer equipment than I do. We worked on trimming the parts square on the table saw, then cut them to size, then cut rabbets. I'm pleased with the results. You might notice that the fit isn't perfect, it's mainly because the thickness of the sheets varies. From a low of about 1.03 to a max of about 1.08. I think that it will work out OK, the back is not very important to me, and I'll try to fix up the fronts. The fronts will eventually be covered up with cloth and molding anyway. After cutting it was on to saw horses in the driveway for test fit, then glue and assembly. The resulting cabinets are just barely manageable. By the time I add the backs and bracing I'll probably have to move them around on a moving dolly. The schedule for the next sunny day that I have free includes speaker holes, internal bracing, and backs for the boxes. Patience is needed, It might be a few weeks until the next update.

[srm51555]

Hey Don,

Nice progress, thanks for the update.

[JeffW]

What are the big blue/aluminum bar clamps?