Bracing and stuffing in a small box

Mass damping works well.

To do what? Adding mass without adding rigidity lowers potential panel resonance frequencies, making them more likely to be excited, and more likely to be heard.

In a woofer it is very counter to killing resonances or more significantly, not excited if you can get any potential pabnel resonances above the bandwidth of the driver in the box.

dave
 
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Damping material effectiveness is proportional to its density. So light fluffy stuff, low density, is ineffective. Heavy rock wool or densely packed fiberglass is very effective. Adding that dense stuffing effectively makes the box volume look larger to the woofer, so that can extend the low end while also lowering the in box Q. Nice looking build. I looked at using that woofer. It has great specifications.
 
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For my latest project I made two subs, each with two opposed 6 1/2 inch drivers, that are mounted inside the enclosure, and held in place by a jacking screw between the magnets . The are made from well braced 6mm MDF, the idea being any mechanical resonance will be higher in frequency than the range of the subs. They are heavily stuffed with cotton wool.
 
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It's just two bolts, one drilled and tapped to take the smaller one, the opposing ends turned to points (to locate in centre drilled holes, already in the speaker magnets) and with a lock nut to stop them from working lose. They push the speaker drivers outward against the speaker enclosure, but I'm only using a 3 watts amp to drive them, so they don't have to be pushed very hard. I am tempted to use soft foam gaskets between the rivers and enclosure, meaning the drivers would "float", and be machanicaly isolated form the enclosure, however I don't think that that's necessary because the thin wall/well braced enclosure has a resonant frequency too far above the range of the sub to be "excited" by it. I'll try and take a picture if we get some sun.
 
It was about 40years ago and I bought a 2.5kg can for a few £s.

I spread it on with a palette knife and then left the box opened without the drivers fitted for a couple of weeks for the solvent to evapoarate.

Years later I used a lead/foam sandwich from noisekiller.

https://www.nkgroup.co.uk › noisekiller

This completely blocks anything from reaching the walls but is heavy, (obviously)
I used it to silence my boat engine - what a massive difference it made.
 
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