Since I’m using the Parts Express 8liter (0.25ft3) curved enclosure Dayton 8 liters Curved Cabinet #302-701 for this design and it’s a bit oversized for the used mid-woofer, I need to reduce the internal volume by approximately 2 liters. I used very dense foam pads which I glued to the upper rear side-walls to reduce the volume. 4mm bitumen pads are glued to the side-walls in the front part of the enclosure to reduce vibrations and to reduce the internal volume as well. I’ve used a 29mm (1 1/8”) bass-reflex port tuned to 45Hz (see pictures).
Even though the W12 mid-woofer is well ventilated it’s very important to chamfer the baffle in order to let the mid-woofer breathe properly. This is also partly the reason why I choose a relatively wide baffle (19cm or 7.5”) for such a small driver unit. I have used less wide enclosures for similar sized driver units before and my conclusion is that many times you get reflections from the side-walls that affect the midrange performance, if the driver isn’t allowed to breathe unrestricted. This is not always clearly visible in measurements, but is clearly noticeable in listening tests.
The enclosure is lightly filled with sheep wool and I use SUPRA Ply 2.0 for internal wiring. SUPRA Cables
I use SUPRA both for signal and loudspeaker cabling in all my designs and HiFi equipment and I think these cables have a great price/performance value.