by Young/South Korea
Finally the CNO-mkII is done and I am listening to them now. Thanks for all the help to reach this point. It is a holiday in Korea and I can crank up the volume without bothering the neighbors too much. Without hesitation I would say I like the sound. I am not good at describing it but CNO has the calmness and lushness at the same time. The only reference I have is my old W15CY mini monitor and the previous TJL2W-T25 I have build with a friend. It wouldn't be fair to compare the bass to the TJL2W with drivers not properly broken-in. But I would say the TJL2W definitely had a deeper bass I could feel when I listen to sound of a drum. But then CNO seems to have more liveliness which I like also. I am going through lots of CDs today and thoroughly enjoying the speakers.
I have tested the impedance of the two with Clio. The two seem to match quite well, other than the very low end, which will probably change with time anyway. Just wanted to make sure the crossovers were build and wired properly, and they seem so. At least I can see the port tuning is right at around 40-42Hz. I tried to use Superior Z-Cap where signal goes through, and used standard Z-cap for 'lossy' circuit like series RLC. CNC milling worked out well and save me a lot of time. I used 1" thick Whispermat for the top, behind the woofer and at the bottom. For other panels, I used 1/2" thick Whispermat. Stuffed the top and bottom with polyester fill and covered it with a small sheet of wool so they don't move around. Also added some good padding to the back of the woofer, and basically followed the TJL2W damping instruction. Proper amount of damping is what worried me all the time, and I think I should be close to the optimal point. As far as finishing the wood is concerned, I would probably give them a few coats of polyurethane later.
I am enclosing a few pictures for you. You can publish them if you like. So many others have build the CNO, and I hope these pictures bring up interests in others to build the same also.
Hello Young. Yes, the CNO is about twice as efficient as the TJL-2W. For the approx. same volume we sacrifice some low-end extension on the CNO. BR Troels