I have posted in the DYI section asking about cabinet plans for these JBL D123's I found at a Thrift in "AcoustiCraft" cabinets.
20.5 X 17 inch 12 inches deep with 3 inch legs. 3/4 inch construction,
2 X 12 inch port along the bottom front. my math has them at 1.80 cubic feet. First JBL's I have ever owned. Listening to them now, the sound stage is amazing, enough highs to ring my old ears. I am starting to fall in love with the single driver sound. I asked about cabinet plans in the hope of getting a bit more bass. But oh what sound as is !