what is the best type of wood and also is ply wood good?

 

Most of us use MDF, some use plywood and even birch. Make sure its stiff an/or braced, and sufficiently strong esp. on the front baffle so that the sub isn't shaking and vibrating the box which wastes energy, lowering efficiency and output.
I like to use 1" MDF for my front baffle, and 3/4" for the other panels, but its up to you.
Just think twice before using particle board. It can be used but you REALLY have to know what you're doing, and any of us asking ?s here obviously aren't that far along lol

 

thanks i'm getting it cut out again but this time in mdf

 

2 layers of 3/4 is stronger than 1". Also cheaper if you dont want to buy two different sized sheets. Mdf isnt completely sealed, you can pick up more than one layer with a shop vac, which is why people resin boxes.

 

And how often do your speakers act like a shop vac?

 

They're the same in theory but vacuums are phased one-way pressurizing you see .

 

They are not at all. A sub pressurizes and rarefies the space anywhere from 15-80 times per second. This is far too fast for there to be any net air movement through the wood.

The shop vac thing is a parlor trick originally capitalized upon by a sound deadener manufacturer about 16years ago to sell their spray product to treat the inside of boxes. It has been erroneously repeated ever since.

 

I was joking (i thought you were) but good to know! Another myth i can cut off the list . Does resining inside and or out strengthen as good as bracing?

 

not so much strengthen, but make sound waves bounce off it better, i heard alot of SPL guys do it.

 

I personally will not use MDF, its dust is just too carcenogenic and it's quality is difficult to discern (many people have said that home depot MDF is much worse quality than other MDF). A good plywood like Baltic Birch or marine grade anything (mahogony is really nice sounding and resists moisture changes very well) will be your best bet. Baltic Birch plywood is also lighter for the same amount of strength when compared to MDF.