seal wood inside cabinet

[pizzachef]

just about done with one of the planet 10 designs.... using bb plywood. holey braces have lots of surfaces... should i seal the wood with polyeurathane or something, either to stabalize the wood or keep slinters from vibrating

[evanc]

I would not bother sealing the insides if they are made of BB plywood. solid would I would....

[karmik]

Plaster accurately, sand to perfection, place black tar. That should provide enough dumping.

[Scottmoose]

Not necessary most of the time with BB ply, except in a very humid environment. Adding tar to one of Dave's cabinets would be counter productive.

[karmik]

How so? Less stray vibrations should be good no? Asking honestly, it's clear i'm the lowliest of newbies here

[Scottmoose]

There's resonance & there's resonance. You cannot remove panel resonance in any practical cabinet, only shunt it to a region where it's not going to cause problems. The principle behind Dave's cabinets is to raise it significantly above the functional BW of the box, where there is little energy left to excite it. Adding damping beyond what is specified in the design isn't likely to bring any benefits & if done excessively may ultimately start to reverse this trend.

[karmik]

So basically planet10 design "shifts" the endemic resonance of every panel far high in the sound spectrum?

I can see why in a situation like that damping more would cause harm. If i understand it correctly, the risk is that the resonance would "fire back" at lower frequencies?

[chrisb]

Originally Posted by karmik

So basically planet10 design "shifts" the endemic resonance of every panel far high in the sound spectrum?

I can see why in a situation like that damping more would cause harm. If i understand it correctly, the risk is that the resonance would "fire back" at lower frequencies?

unless the damping scheme / materials can magically transport those vibrations to another fixed point in the time space continuum (you're welcome Jack Harkness fans), all it's likely to do is slow down the rate at which the "absorbed" energy is dissipated - often to the detriment of the music's transient response

that piece of baffle-gab fluff brought to you by the folks at Barrowman Labs


I've often finished exposed surfaces of ports, horn mouths, etc, but I wouldn't worry about sealing inside of plywood cabinets

[boywonder]

Karmik: Sometimes petroleum based tar/roof cement can out gas solvents inside a cabinet, and these solvents can degrade/melt foam surrounds, driver adhesives, etc.

Just something to keep in mind....

[karmik]

Originally Posted by chrisb

unless the damping scheme / materials can magically transport those vibrations to another fixed point in the time space continuum (you're welcome Jack Harkness fans), all it's likely to do is slow down the rate at which the "absorbed" energy is dissipated - often to the detriment of the music's transient response

that piece of baffle-gab fluff brought to you by the folks at Barrowman Labs


I've often finished exposed surfaces of ports, horn mouths, etc, but I wouldn't worry about sealing inside of plywood cabinets

Major Respect for the Dr.Who/Torchwood reference, you warmed my heart!

Originally Posted by boywonder

Karmik: Sometimes petroleum based tar/roof cement can out gas solvents inside a cabinet, and these solvents can degrade/melt foam surrounds, driver adhesives, etc.

Just something to keep in mind....

Blast it. I thought black tar was a must in basically every speaker build. Are you telling me it's not that common and that it can even be harmful? How many speakers out of 10 do you see it used in?

The more i read about speaker building, the less i know. Oh well.