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Damping material for ported sub.
Damping material for ported sub.
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Old 30th December 2012, 05:10 PM   #1
Grv43297 is offline Grv43297
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Default Damping material for ported sub.

Hey guyz! i am peparing a samll sub for my home which contains 5 inch driver. Its an active sub powered by TDA2030 and NE5532 as low pass filter. The enclosure type is ported with T-Line design. Now, my question is about, what type of damping material should i use to make it sound better and how to apply fiber glass/glass wool on T-line design . does it really helpful? I read it that damping material acts like having a large enclosure for driver. what should i do? do i install damping material or just it ok as it is? please guyz help me to sort it out soon.

Girish Rai Vasuja
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Old 3rd January 2013, 04:20 PM   #2
Inductor is offline Inductor  Portugal
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T-Line design. Some people have some more experience. Try to follow projects in other threads. I'm more used to the BR or sealed box.
Generally speaking "internal absorption using absorptive materials (often called "damping"), such as glass wool, wool, or synthetic fiber batting, within the enclosure".
Loudspeaker - Wikipedia, the free encyclopedia
Try to avoid using glass wool and use rockwool instead.
Wool it's a very "high quality" damping material, very efficient.
Try using a website for various ideas (materials) of what you are doing (go also to the main TL websites).
Click below to go to
TL example: http://www.troelsgravesen.dk/download/ATR25.pdf
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Old 3rd January 2013, 09:11 PM   #3
Shadydave is offline Shadydave  United States
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Default Stuffing material vs. Damping material

I believe in a line you want to use very light material, not rockwool, standard fiberglass or even Acousta-stuff Polyfill ETC..
Although the very lightest fiberglass is about right.(I believe R-19, 6" thick wall batts)
Something between 0.4 and 0.5 lbs. per ft.^3.
A very good material is long hair wool.
This will do about 2 ft.^3
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Last edited by Shadydave; 3rd January 2013 at 09:12 PM. Reason: Speilling again
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Old 3rd January 2013, 09:29 PM   #4
DrDyna is offline DrDyna  United States
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+1 for standard itchy fiberglass insulation you can get from a home improvement store. I've never had any trouble with it. Roll it out and staple it to the inside of the enclosure.

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Old 3rd January 2013, 10:16 PM   #5
scott17 is offline scott17
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I use fiberglass ceiling tiles with the plastic peeled off. Easy to cut with a razor knife. Glued on with spray adhesive.
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Old 3rd January 2013, 10:29 PM   #6
Cal Weldon is offline Cal Weldon  Canada
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Damping material for ported sub.
You can do what Scott says and leave the plastic on. Just glue the plastic side to the cabinet.
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Old 4th January 2013, 02:32 PM   #7
Grv43297 is offline Grv43297
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Thanx alot guys for helping... but do i really need damping material as my sub is only 5.25 inches??
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Old 5th January 2013, 02:00 PM   #8
duanebrow is offline duanebrow  United States
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Dampening is normally done in the top half (nearer the closed end) to smooth ripples caused by the line. This is above the bass frequencies. Fill doesn't help much at lower frequency. It becomes less effective as frequency goes down. Some TL modeling programs can model this.

To much fill can cause loss of bass output. This is often adjusted to help adjust the speaker to a room.
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Old 6th January 2013, 09:18 PM   #9
tvrgeek is offline tvrgeek  United States
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My tests showed fiberglass to be great, but I don't use it in any ported enclosure as I don't want the speaker pumping tiny pieces of glass into the air. So, I use wool or the expensive boutique Daycron. (Acoustastuff) The craft store polyfill is totally useless.

Even if you don't progressively damp the TL, I would stuff the chamber behind fairly firmly to smooth out the reflections.

My big panel absorbers are made of damaged discounted ceiling tiles. Got them for about half. Three layers, layer of cotton batting, and wow! I don't have a easy way to get full sheets of OC panels.

Just wondering Grv, how do you expect a 5 inch driver to act as a sub? Even if the chart says it can be tuned that low, it would have to move inches. About a 10 is the starting point. Maybe 8 for an under desk low level fill. You just plain have to move more air than a 5 can do.
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Old 7th January 2013, 04:46 PM   #10
▀art West-VL. is offline ▀art West-VL.  Belgium
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Interesting to read you say polyfill is useless. Is that the stuff I find in pillows and filter the water in the aquarium with?
Break in your loudspeakers at 35% RMS power Right-click'save as...'
Brown noise mono 192kbps(hit "repeat")
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