B U I L D I N G A N E N C L
Calculating speaker enclosure volume is a five step procedure.
(Make sure you do not forget to subtract the thickness of the wood that you have selected to use to build your enclosure.)
Step One: Measure Height
Step Two: Measure Width
Step Three: Measure Depth
Step Four: Height x Width x Depth
Step Five: Divide the results were in step four by 1728 (12" x 12" x 12"=1728 which equals to 1.0 cu ft.)
Complete formula should look like this Height x Width x Depth / 1728 =__________
Below are illustrated versions of all the steps that you should take.
(FOR EXAMPLE ONLY)
O
S U R E
Step One
12"
18"
19.5"
Step Two
13.5"
Step Three Side View
12"
The wood that we are using is 0.75" thick
The 1.5 that you see in the formula is the thickness of the wood.
Calculating thickness of wood:
Measure how thick the wood is then multiply by two. The reason that you are multiplying by two is each side of the enclosure.
Left + Right=1.5
Top + Bottom=1.5
13.5" 
Front + Back=1.5
.75 x 2=1.50
18 x 12 x 12=2592
2592 / 1728=1.5
Patent No: US D478,556 S
7Patent No: US 6,601,645 B1
Patent No: US 6,656,000 B2
1.5 cu. ft. is the results for this enclosure