if using 1" thick MDF,,is internal bracing still needed? - diyAudio
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Old 13th October 2013, 01:43 PM   #1
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Default if using 1" thick MDF,,is internal bracing still needed?

It would be for a 2 cubic foot sealed enclosure. With walls that thick it would be pretty stout,,just wondering if the bracing would be overkill. It would be for a 12" Dayton Ultimax,,
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Old 13th October 2013, 02:26 PM   #2
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Definitely, bracing is more effective than thicker walls.
Here's a research.
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Old 13th October 2013, 02:34 PM   #3
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Alrighty then. thanks for the link. Can't argue with data and graphs. I'll stick with 3/4" MDF braced very well.
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Old 15th October 2013, 10:01 AM   #4
ODougbo is offline ODougbo  United States
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I was a fan of 1" mdf for a long time, now those boxes are stacked in a pile and in the process re-building all of them. I like the idea of laminating mdf/plywood, 1/2" on 1/2" e.g.
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Old 25th October 2013, 10:04 AM   #5
Juhazi is offline Juhazi  Finland
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When we consider just subwoofers, box wall "ringing" at several hundreds of Hz or kHz range is not an issue (looking at danny_66's link). The problem is ballooning with sound pressure which causes all kinds of vibrations and distortion peaks.

Traditional and proven way to make a good bass cab is to use bracing, it is effective against ballooning. Wool or lining are not needed, with the exception of filling sealed cabs to get a little higher Q.

Lamination is the best way to make a good full range speaker's cab, and add bracing there too! Inside should be lined or filled too.
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Old 25th October 2013, 01:32 PM   #6
colofan is offline colofan  United States
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Well missing from the study at least the translated version is what is the input signal going into the box? If you use a ported design the over and under pressure is not what is being modeled here (sealed box).

If the experiment was to use a pink noise generation with a narrow bandpass of what actually frequency would being developed in a sub-woofer I would concur that the data points to better bracing however it does not.

Also of note in secondary output could be measured with a contact sensor on each panel to see how much engery is be loss through the side and back walls of a box.
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Old 25th October 2013, 06:57 PM   #7
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Hello, the thickness determines how far the span can go.
The mathematics is complex, but basically when you double the thickness you can double the width without adding bracing.
So 6" with a 1/2" panel thickness is equal to 12" and 1" thickness.
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Old 25th October 2013, 07:19 PM   #8
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Quote:
Originally Posted by rockironwebb View Post
I'll stick with 3/4" MDF braced very well.
You would be further ahead with 18mm (3/4") quality ply, or even 15mm.

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Old 25th October 2013, 07:19 PM   #9
brig001 is offline brig001  United Kingdom
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Quote:
Originally Posted by colofan View Post
If you use a ported design the over and under pressure is not what is being modeled here (sealed box).
True. Counter intuitively you will need a more rigid box if it is ported.
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