i looked at the cost of building a solid one, and decided a used one made more sense.
i bought a Demeter Silent Speaker
Demeter Silent Speaker Chamber (SSC-1) -- "The SSC-1 Silent Speaker Chamber is the answer for those trying to achieve a full bodied electric guitar sound without disturbing the neighbors. Features include an adjustable built-in mic stand with XLR output and 1/4" input jacks on the exterior. Ideal for live recording and live situations where leakage is a problem Hand made of 3/4" marine grade plywood with heavy duty molded corners, fully insulated and wrapped in durable black carpet. Available loaded with a 12" 80 watt Eminence speaker. (SSC-UL) or unloaded (SSC-1U). The SSC-1's dimensions are 30" by 18" by 18". Unloaded the SSC-1 weighs 45 lbs Loaded 50 lbs.
Demeter Amplification - Products
iso cab open with boogie
inside pic:
i added the auralex sound treatment on the interior, to cut down on reflective waves.....
i have (3) different speakers i can load in it, rated from 100 watts all the way down to 15 watts (a Eminence Legend)
i prefer the low watt speakers, and running the iso cab at lower volumes.
too much volume inside, i don't care what the dimensions are, it's going to sound compressed.