rogerwilco82 Posted October 4, 2010 Share Posted October 4, 2010 Hi, I'm driving an Bob Crites Cornscala using all the parts from Bob, including his crossover. I recently read about someone who changed the lower crossover frequency from 500Hz to 600Hz, getting a relly good result. Since the DIY world is kind of an "try and error" experience, I thought about trying a 600Hz crossing so that I could build my own opinion. Is there someone who already tried this? What do I need to change? The soldering will be no problem, but I'm pretty new to all the crossover topic so I don't wanna fool around with the crossover without fully understand the theory behind it. I appreciate any advice Robert Quote Link to comment Share on other sites More sharing options...
Guest David H Posted October 4, 2010 Share Posted October 4, 2010 Robert, there is very little difference going from 500-600hz especially with a first order filter. It may not even be audible. Additionally raising the crossover frequency is often done to protect the midrange driver or because the Fc of the mid horn is not low enough, in either case I think you are safe with your horn and driver. If you want to make a signifigant change you may want to try a different network altogether. For Cornscala I am anxious to try the ALK AP12-600 with the AP15-6000 I like the design, It's basically a 2nd order woofer filter with a universal top end which incorporates tweeter attenuation. To this day I have not heard a bad sounding Cornscala. Dave Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted October 4, 2010 Share Posted October 4, 2010 Dave is right about the 500 - 600 Hz change. The networks he is thinking of are the AP12-600 and the AP15-6000. They are step above the Universal network in that the woofer to squawker section is specific to one crossover frequency and therefore a single speaker. Al K. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted October 4, 2010 Share Posted October 4, 2010 I think the networks he is thinking of are the AP12-600 and the AP15-6000. Those are the ones, I edited my initial post with the corrections. Dave Quote Link to comment Share on other sites More sharing options...
rogerwilco82 Posted October 5, 2010 Author Share Posted October 5, 2010 Thank you guys for the advice! So I will try the AP12-600 and the AP15-6000. I've found the AP12-600 designs on Al's site - is the AP15-6000 design also free for download? Also: Will the crossover change the frequency response especially for lower frequencys? I sometimes think the bass between 60 and 100Hz could be more...let's say "bloomy". Robert Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted October 5, 2010 Share Posted October 5, 2010 The AP15-6000 network is simply the squawker to tweeter crossover section of the Universal built on a separate board from the woofer to squawker section. Al K. Quote Link to comment Share on other sites More sharing options...
rogerwilco82 Posted October 5, 2010 Author Share Posted October 5, 2010 Hi Al K., thanks for your advice! So am I right that I "only" have to add the tweeter section of the universal crossover? Adding these 3 parts (2.2 uFd, 1.0 uFd, 6.2 uFd)? Is there a kit availlable combining the AP12-600 with the AP15-6000 tweeter section? Robert Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted October 5, 2010 Share Posted October 5, 2010 Robert, I don't follow your thinking. The AP15-6000 is the top section of the Universal PLUS the tweeter attenuator. It has two inductors and 3 caps. The squawker transformer is located on the AP12-600. The two are connected together by a 3-wire cable that makes each module compatible with my extreme-slope networks. There is no kit version for it. You would need to get all the parts yourself to make it a DIY project. Al K. Quote Link to comment Share on other sites More sharing options...
rogerwilco82 Posted October 5, 2010 Author Share Posted October 5, 2010 sorry for being unprecise. My idea was to take the AP12-600 (where I would connect the woofer and squawker) and add the tweeter section of the universal network from your "xover.zip". Robert Quote Link to comment Share on other sites More sharing options...
Guest David H Posted October 5, 2010 Share Posted October 5, 2010 sorry for being unprecise. My idea was to take the AP12-600 (where I would connect the woofer and squawker) and add the tweeter section of the universal network from your "xover.zip". Robert Robert, that is the general idea, but for use in a Cornscala you must add the tweeter attenuator as well.Dave Quote Link to comment Share on other sites More sharing options...
rogerwilco82 Posted October 5, 2010 Author Share Posted October 5, 2010 Maybe I get it wrong - when I look at the AP12-600 and the AP15-6000 on Al's site, I'm ending up doubling the squawker part - is this right? Do I really need the tweeter attenuator? I thought I can also do this with an auto-transformer... Robert Quote Link to comment Share on other sites More sharing options...
Guest David H Posted October 5, 2010 Share Posted October 5, 2010 Maybe I get it wrong - when I look at the AP12-600 and the AP15-6000 on Al's site, I'm ending up doubling the squawker part - is this right? Do I really need the tweeter attenuator? I thought I can also do this with an auto-transformer... Robert You are not doubling the mid section, you need both pieces, and the tweeter attenuator is necessary. Quote Link to comment Share on other sites More sharing options...
rogerwilco82 Posted October 5, 2010 Author Share Posted October 5, 2010 Thank you Dave, I thought I would double some parts when I use the AP12-600 and the AP15-6000. When I need those both I better buy them from Al K.! I thought I need to change something - that's why I wanted to DIM (Do it Myself []) Robert Quote Link to comment Share on other sites More sharing options...
radiogram Posted October 5, 2010 Share Posted October 5, 2010 Robert: I agree with others that with a 1st order network moving from 500 to 600Hz is not worth it. Also, not to confuse you, but I spent a few hours at ALK's house last Sunday, and I was mightilyy impressed with the the JBL mid range driver + Al's trachorn, he uses in his modifed Belles. It had a certain palpability and naturanlness that was so good and that too I later realized that the source was FM Radio and not CD or Vinyl! I think he had the JBL 2426 but I do not exactly remember the model. You can check with Al on the JBL driver as well, since I am contemplating myself on replacing my K55/K400 combo (which I a personally do not find that great and actualy prefer the Herseys K53/K701 combo in comparison) with JBLs and Al's Trachorn myself. Just another flavor to think about. Whatever direction you go, good luck and have fun. Regards Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted October 5, 2010 Share Posted October 5, 2010 He's right. The drivers I am using are the JBL 2426h. It's the 8 Ohms version, The 2426j is the 15 Ohm version. They make excellent squawker drivers. They are supposed to go out to about 15 Khz but start to show major roll off above about 6 Khz. I have used them 2-way but require EQing to do it. AL k. Quote Link to comment Share on other sites More sharing options...
Mighty Favog Posted October 7, 2010 Share Posted October 7, 2010 Robert, I sent you an e-mail about your Cornscalas. Thanks for any input you have! -Tom Quote Link to comment Share on other sites More sharing options...
amadork9 Posted October 30, 2010 Share Posted October 30, 2010 I have cornwall ll's I converted to cornscalas by way of ph800 horn, k55m, ap12-500 and es5800 and achieved a factory look, mx130 and mc7270, excellent sounding results, though thinking about trying the fastrac with jbl driver 2426 Quote Link to comment Share on other sites More sharing options...
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