Many hears ago, in a Hi-Fi show, I listened the ProAc Response Two speakers and I was really impressed by their performance. These speakers just simply disappeared, leaving behind an ambient soundfield that changed very little with head movement. Driven by an excellent Audio Reserch tube pre/power amplifier, they had put the singer right here in the room with me!! Also all acoustic instruments like the guitars, violins, percussions were played with a breathtaking sense of 3-D realism. In last September I saw among ads sale two 6.5″ Scanspeak 18W8543 polypropylene bass/midrange drivers and two ¾” dome tweeters D2010 Scanspeak and remembering the previous ProAc listen experience ( Response two speakers were equipped with these drivers ) I thought….mmh…..why not?
To build the cabinet I choose 19 mm thick marine type plywood. To compensate the time delay tweeter-woofer emission I adopt a sloping baffle. Furthermore, I put a 30x30mm battens in the internal rear perimeter to allow the removable rear panel ( to adjust crossover, damping and so on ). A 19x80x200 mm bracing is put between the two sides to minimize the box vibrations and silicone sealant on all internal edges to seal any micro cracks. The single front-mounted tuning port is a slot 12 mm height and width as a baffle ( 200 mm ). The total length is 140,2 mm. As you can see in the photos, the internal sides ( excluding the front panel and the bottom ) are coated with 30mm dacron fibre mat. In the tweeter cell crossover I suggest to use 5 W non inductive resistors and MKP high quality capacitors as Mundorf, AuriCap, Multicap or similar. The coil for woofer cell MUST BE air wrapped, 1.4 mm Cu to minimize series resistance. For the other coil is sufficient 0,5-0,6 mm Cu diameter. The red soft carpet put in the baffle smooth out the 6 mm speaker edges.