chops Posted March 30, 2006 Share Posted March 30, 2006 Chops. Those are "pole mounts" for the K77 or the CT125. This will place the tweeter up flush with the Altec 811b and to the front of the cabinet. Ah, I see. But what about this midrange horn of Bob's? Quote Link to comment Share on other sites More sharing options...
jwc Posted March 30, 2006 Author Share Posted March 30, 2006 Hmm. Fraid to elaborate. Might still be top Secret. jc Quote Link to comment Share on other sites More sharing options...
chops Posted March 30, 2006 Share Posted March 30, 2006 Oh, gotcha! No biggie. [] Quote Link to comment Share on other sites More sharing options...
BEC Posted March 30, 2006 Share Posted March 30, 2006 Chops, Not really secret. I am just evaluating a new larger and in my opinion better horn for a Cornwall or Cornscala than the K-600 original horn. Lots bigger than the K-600 but will fit in a Cornwall size cabinet. I usually have a few new things cooking. How about this one. I am working on still another new 15 inch woofer. That one is about another month out. JC doesn't even know about that one. Bob Quote Link to comment Share on other sites More sharing options...
chops Posted March 31, 2006 Share Posted March 31, 2006 Chops, Not really secret. I am just evaluating a new larger and in my opinion better horn for a Cornwall or Cornscala than the K-600 original horn. Lots bigger than the K-600 but will fit in a Cornwall size cabinet. I usually have a few new things cooking. How about this one. I am working on still another new 15 inch woofer. That one is about another month out. JC doesn't even know about that one. Bob WOW! Look at that beast! [] I'm assuming that it uses the K55-V driver? Quote Link to comment Share on other sites More sharing options...
BEC Posted March 31, 2006 Share Posted March 31, 2006 Yep, a K-55V or M screws right on. Bob Quote Link to comment Share on other sites More sharing options...
jwc Posted March 31, 2006 Author Share Posted March 31, 2006 A new woofer. That would figure. Bob you're killing me. There is already too many things to play with. Quote Link to comment Share on other sites More sharing options...
BEC Posted March 31, 2006 Share Posted March 31, 2006 jc, This new woofer is not a major change over the ones you have now. Should be rather like the difference between yellow colored capacitors and black ones. I expect to have the first two sample woofers in a few days. Bob Quote Link to comment Share on other sites More sharing options...
jorjen Posted March 31, 2006 Share Posted March 31, 2006 Wow JC, nice work. Interestingly enough, I have been thinking of an almost identical project. I had planned to use Al's Trachorn and JBL 2404H's. I had this combo in my Khorns and loved it. Quote Link to comment Share on other sites More sharing options...
BS Button Posted March 31, 2006 Share Posted March 31, 2006 Good grief!, where has that sucker been? Bob, this one's a bit heftier than the first one, eh? I'm ready to replace that 600, right now....well, maybe.. BS PS. Jorjen's back, my original hero. Your re-build of those Cornwalls (Cherry) ispired me to get back with it... Quote Link to comment Share on other sites More sharing options...
jwc Posted March 31, 2006 Author Share Posted March 31, 2006 Todd. I made this cabinet to accomidate Bob's horn if I ever wanted to try and switch. I know the dimensions. I already have a Cornscala and I was more inclined for now to build a more-like Cornwall that is more wife appealing in looks. I thought I could give the CW3 a run for the money. This box should test out that woofer well and will have to perform in the upper bass area up to 700Hz. Quote Link to comment Share on other sites More sharing options...
jorjen Posted March 31, 2006 Share Posted March 31, 2006 Thanks BS, nice of you to mention it. I was never too far away, just had to realign(misalign as far as I am concerned[])my priorities for a brief period. Unfortunately during that brief period I panicked like a wuss and sold my two channel gear. Consequently I am starting over from square one. I even asked Patrick if he would sell the Cherry Cornwalls back to me and he said...no dice[]. I will not even attempt to ask Bob to sell the Khorns back to me. He has a life long love affair going with those puppies already. Well, La Scalas tomorrow and then we will see what the next day brings. Quote Link to comment Share on other sites More sharing options...
jwc Posted March 31, 2006 Author Share Posted March 31, 2006 Cut my ports to 10inch length. They are actually 11inches but by the way these are suppose to work, that last inch of length doesnt count. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> Discovered something nice. I will not have to unscrew the woofer every time I need to resize the port. The back end of the port flare is much smaller than the front and therefore will fit through the cutout. Quote Link to comment Share on other sites More sharing options...
jwc Posted March 31, 2006 Author Share Posted March 31, 2006 My wife wanted me to say that she very much approves so far. If these things sound at least as good as my Cornscalas, I may have to send the Cornscalas to the lakehouse and keep the TallCorns here. Now the part that will be a pain. RTAin' the Bass bins. I was plannin on just hooking the woofer up to a 2.5 mHy inductor and getting the curve. Any other suggestions? jc Quote Link to comment Share on other sites More sharing options...
BS Button Posted March 31, 2006 Share Posted March 31, 2006 Thanks BS, nice of you to mention it. I was never too far away, just had to realign(misalign as far as I am concerned[])my priorities for a brief period. Unfortunately during that brief period I panicked like a wuss and sold my two channel gear. Consequently I am starting over from square one. I even asked Patrick if he would sell the Cherry Cornwalls back to me and he said...no dice[]. I will not even attempt to ask Bob to sell the Khorns back to me. He has a life long love affair going with those puppies already. Well, La Scalas tomorrow and then we will see what the next day brings. Jorjen, I firstly apologize to JC for the thread swap. Jorjen, I'd like to see a re-veneer of some La Scala's. Mine are black, look good, but well, ya know. Those Cherry Cornwalls are, were, well, cherry. JC, you crack me up. BS Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted April 1, 2006 Share Posted April 1, 2006 well for regular ports non flared, the port can actually be up to 1 inch shorter than needed because the air still travels the same way it does in a port for about 1 inch or so.... until it mixes with the standing air With flares you might get some effect but since the flare's job is to lower the psi coming out of the port the gain fron the port is lost. But you should not lose an inch, where did you read that the last inch does not count? Quote Link to comment Share on other sites More sharing options...
jwc Posted April 1, 2006 Author Share Posted April 1, 2006 Well this is part of what the included materials say with the Precision Port 1. Calculate length of port needed: (Lv is the calculated length) 2. Determine proper speaker & port placement before cutting any holes. The Precision Port should be placed at least one port diameter away from any inside walls, if possible. 3. Trim center tube to 5" shorter than Lv from step one. 4. The Precision Port should be 1" longer than Lv when assembled. Quote Link to comment Share on other sites More sharing options...
jwc Posted April 1, 2006 Author Share Posted April 1, 2006 I went through a preliminary RTA session today with the TallCorn Bass Bin. I did it 3 times. Once w/o an inductor, once with a 2.5 mHy inductor, and one with the ESN700. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> The mic is 1 meter from the Bass bin. The software is calibrated to which the SPL should be real close to what it really is. Now the purpose of this is to get the tuning right. My goal again is to just get a flat response. Im not sure if I achieved this yet. Please take a look at the curves and let me know what you think. I would have thought I would need shorter ports. While looking at these, ignore the in between bars beyond about 60Hz. That is just where I skipped some frequencies so that it wouldnt take forever. I need some strong suggestions on how to interpret what is going on below 60Hz so that I can make a decision on what port length to try next. I know my room plays a big part in this. Couple of conclusions so far. The 2.5 mHy inductor only makes the rolloff a little slower than the woofer would do naturally on its own. I found this disappointing. Im not sure what the crossover point should be. Hell, I could hear frequencies coming from the woofer after 10000Hz. I couldnt believe this. Now for the real joy. I give Al a lot of credit on this one. I cant believe the perfection with the ESN. I now strongly believe that the K33 IS 6 OHMS in series with the 1.0 mHy inductor. Notice the curve for that network. It drops 20dB right after 700Hz. I mean right at it. Damn good job. For those who may not understand these images. A simple way to look at them is that the cabinet and the way it is tuned is a reflection on the left side of the curve/bars. The right side is impacted by the low pass filter. jc Quote Link to comment Share on other sites More sharing options...
jwc Posted April 1, 2006 Author Share Posted April 1, 2006 No inductor. This would be the natural rolloff of the woofer. Quote Link to comment Share on other sites More sharing options...
jwc Posted April 1, 2006 Author Share Posted April 1, 2006 2.5 mHy inductor. This is what you guys have in all those first order networks. Quote Link to comment Share on other sites More sharing options...
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