# 1st sub build CSS trio12



## steve1616 (Apr 6, 2009)

I am well on my way to my first sub build, and here are some quick picks I took of my progress. This sub has a tuning frequency of 21 Hz, and the inside net volume of the box including the woofer, bracing, and etc. is very close to 4.4 cubic feet. I actually made my box fit the slot port easier by building the depth to work together with my slot port depth.


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## mechman (Feb 8, 2007)

Looks good Steve! :T


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## steve1616 (Apr 6, 2009)

I never see anyone try to seal the inside of the box with silicon, but would 100% silicone be acceptable to use for an extra sealer on the inside of the box? Also, most people seem to use cheap fiberglass insulation as a cheap dampener, and I have some of that stuff on hand. Is that as good as anything else for a sub? 

My last question has to do with rounding the edges of the box. What is the biggest roundover bit I can use without weakening anything? The box is made of 3/4" MDF. 

Thanks


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## Mike P. (Apr 6, 2007)

I always run a bead of hot glue along all inside seams just to be sure. Silicone will do the same thing as long as it is cured before you mount the driver. Rumor has it silicone fumes will eat the glue that holds the surround to the frame.

Fiberglass works well for absorbing internal resonances, some people say it's a health issue.

I use a 3/4" round over on 3/4" material. Make sure all screws are partial countersunk. Router bit + screw head = bad. Been there.


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## steve1616 (Apr 6, 2009)

Has anyone ever used the insulation foam called "great stuff". I wonder if this would work good to seal the seams of the box? It is suppose to be airtight, and it seems to stick to everything.


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## Mike P. (Apr 6, 2007)

If it's an expandable foam it will work although it may be a bit messy.


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