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Old 16th February 2009, 06:50 PM   #11
JLC7 is offline JLC7  United States
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Well I opened one of the speakers and applied some damping material in it. All I had on hand was about 1/2 lb. of 'acousta-stuf' and 2 old sweaters.

Here's a plot of the same speaker with and without the added damping. The black line is the speaker with the added damping. The higher frequency differences are due to the mic not being at exactly the same angle relative to the tweeter.

Doesn't seem like much changed.

Click the image to open in full size.

I suppose there's not much else that can be done?
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Old 16th February 2009, 08:02 PM   #12
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You'll need more than 1/2lb of the stuff to make a dramatic difference. See above. But the design itself is likely to be fundamentally flawed, so there's only so far you can go. Get some more stuffing material first however before making any major decisions.
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Old 16th February 2009, 08:05 PM   #13
JLC7 is offline JLC7  United States
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Anything else I could use in place of poly-fiber damping material? I have a few more out of fashion sweaters I could throw in.

Would those be viable?
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Old 16th February 2009, 09:22 PM   #14
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Unlikely. You won't get anything like an even density & the damping properties of the material itself (which does make a large difference) are an unknown. Fiberglass is good, although it's nasty stuff to work with.

Exactly what are these speakers BTW (if you know)?
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Old 16th February 2009, 09:37 PM   #15
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They are DCM Timewindow 3's of Steve Eberbach's design. Same Steve who designed the original Timewindow speaker from the 70's. The original timewindows don't use TL design to my knowledge. They're just ported, which may explain why they don't have that problem in this room either.
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Old 16th February 2009, 09:50 PM   #16
JLC7 is offline JLC7  United States
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Even though it made it worse, here's a plot with a ton of stuffing added just for kicks.

Click the image to open in full size.

I'll have to consider if I want to spend any more money on literal fluff. Are there cheap options for damping material? For reference 5lb's of acousta-stuf runs $35 + shipping at partsexpress. Haven't checked what madisound has yet.
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Old 16th February 2009, 10:32 PM   #17
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Get thee down to the craft shop or a place that sells cheap bedding & buy some hollow-fiber pillow stuffing, or some cheap pillows with the same & rip out what you require.

Looks to me like a duff design with too small a Vp. Still, worth trying. Without knowing the driver specs., & exact cabinet / line dimensions, we're flying blind anyway.
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Old 16th February 2009, 10:34 PM   #18
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I'm thinking it might be time to convert it to another alignment.

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Old 17th February 2009, 10:29 AM   #19
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Sounds favourite.
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Old 17th February 2009, 01:39 PM   #20
JLC7 is offline JLC7  United States
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What would that involve? Seems like changing the length/# of ports is hard enough. I'm open to suggestions though as long as they're not too extreme.
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