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Multi-Way Conventional loudspeakers with crossovers

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Old 1st October 2012, 10:10 AM   #101
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Join Date: Feb 2012
Location: Brisvegas
I put a thin line around the box to simulate what I think you said...
Also a picture of the MDF rings.
Yeah I got a bit lost with the shark bites too, I can see the shape but not the implimentation.
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File Type: jpg String Around.jpg (65.5 KB, 114 views)
File Type: jpg MDF Rings.jpg (142.1 KB, 115 views)
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Old 1st October 2012, 10:21 AM   #102
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Talking Shark attack...!

Hi Zmyrna,

I have never tried it with H frames, but the principal would be the same as with U frames.
On really shallow front horns / H frames / wings you might not get much benefit as there wont be much " cuppy " resonance going on in the first place.
But as soon as the front to rear length of the H starts to get longer comparedc to the width, the shark bites will really help a lot.

If you do go to an Aqua Park to get your modifications...I would advise removing the drivers first as you dont want them getting splashed if Jaws is in a bad mood...!!
Cheers
Derek.
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Old 1st October 2012, 02:56 PM   #103
puppet is offline puppet  United States
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I sort of remember a post where Jack Caldwell mentioned how the wave propagates right off the mouth of the frame(s). So the cancellation calculation would not include the distances inside the enclosure ... just across the exterior (in the H frame case).

I think that when you model this in Edge, as JC's observation, the resulting frequency cutoff works out closer to reality. (That would be along the line of what you posted in #101 Silent)

Now if Overkill is talking about an actual (shallow) flare beginning at the driver and returning on the back side ... I can see the measurement for cancellation calculation beginning/ending at the driver .. similar to the flat baffle scenario.

If the flare depth increases without additional enclosure width, I think you start heading toward what Mr. Caldwell had discussed ... wave front emanation at the mouth.

I think that this is why Edge has trouble predicting "frames". As you angle the wings off plane toward 90*, the point where the wave seems to emanate changes a little. You'll need to build/measure to be 100% sure.
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Old 2nd October 2012, 12:50 AM   #104
CLS is offline CLS  Taiwan
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Location: Taiwan
For path lengths or structural strength, thick baffle is not very effective.

Soft support or even fully suspension will give you far less vibration (on the baffle). Search "swing".

----------

And, don't think this is the last speaker you'd build, so you put everything the best on it. Once you started, you'll keep building. It's an ever lasting journey. By this viewpoint, I'd suggest not to spend too much material onto a single project (unless you've found the buyer). Or they'll be pilling up much faster than you'd expect.
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Old 2nd October 2012, 01:01 AM   #105
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Join Date: Feb 2012
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Yeah I donít like the ring idea as much as I once didÖ Might just grab a couple of the 600 x 1200 sheets I have sitting in the shed and whack a couple of big holes in them and mount the drivers for now... Not ideal, not scientific, but better than drivers sitting on the floor, and while Iím at it I might just mount the 2 x 12MUs in there as well.

As you say I will make many boxes before I get to the ultimate sound, and it probably will take a fair bit of trial and error, sorting theory from practice. Just thinking the hexagon may not be as complicated to build as I first thought but I need to buy a 60 degree V cutter to build one, so for now I might just knock up a simple test bed.
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