Electro-Voice Professional Sound Reinforcement Products used to provide Builder’s Plans for a series of speaker cabinets called the “TL Series Low-Frequency Loudspeaker Systems.”
The TL806 was a small ported cabinet designed specifically for the EVM12L:
The Electro-Voice TL806 low frequency loudspeaker system is a vented-box (bass-reflex) design with gross internal volume of 1.3 cu. ft. The system has been designed for use with the Electro-Voice EVM12L 12 inch loudspeaker.
Recently many people have discovered what a nice job this cabinet did to complement the driver (speaker) and that the cabinet works very well with a wide range of other guitar speakers. It is a nice bonus that the cabinet can be easily made from 3/4″ plywood, 2 1/2″ x 3/4″ strapping material, brads/staples and glue in a simple home shop.
The cabinet’s outside dimensions were: 14 1/2″ wide by 17 3/4″ high by 13 1/2″ deep. The design was carefully crafted to just barely clear the mounting dimensions of a 12 inch driver (front mounted).
When I went to build a couple of these I scaled the height so that a standard Dumble-like head could be perched upon a couple of speaker cabinets lying on their side (see photo). I believe that Brian’s test results are based on cabinets close to the original dimensions, but with an internal construction that doesn’t rely on strapping.