Hashimoto Posted November 14, 2009 Share Posted November 14, 2009 Here are pics of my DIY AP-12 600 crossovers built from Al's design. Every one of Al's upgrades to my Belles have improved the sound, starting with his universal crossovers, then Trachorns, now the AP-12s with GPA 902s and Beyma tweeters, using the universals as the squawker/tweeter network. Al always promptly and patiently answered all my questions. Thanks, Al. Quote Link to comment Share on other sites More sharing options...
Hashimoto Posted November 14, 2009 Author Share Posted November 14, 2009 another pic of the AP-12 with the universals Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted November 15, 2009 Share Posted November 15, 2009 Geoff, Nice job on the AP1-600. I think you are the first one to try that combination. I think a 2nd order 600 Hz low crossover for the Belle over the low crossover in the Universal is a good idea. I like it. I'm curious where you have the squawker connected. There's two 3619 transformers there. My intention was to keep using the one on the Universal network when feeding output from a low crossover into the bi-amp input. What is the one on the AP12 doing? Al K. . Quote Link to comment Share on other sites More sharing options...
Hashimoto Posted November 15, 2009 Author Share Posted November 15, 2009 Hi Al. The setup is currently 3 way, so I have the strap removed on the AP-12s and the "high out" terminals going to the "biamp" connections on the universal networks, where the 902s and Beymas are connected. I included the 3619s on the AP-12s because I would like to try them as a simple two way with the 902s at some point, but they are not presently used. A couple of questions for you: my 902s have 16 ohm diaphragms. How much does this change the impedance of the network? I have also simply observed the polarity of the squawker and tweeter connections at the terminals of the universal networks. Do they need to be reversed? Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted November 15, 2009 Share Posted November 15, 2009 Geoff, Don't worry about the 16 Ohm driver. It simply results in a 3 dB higher setting on the transformer for the same output level. The result is the same impedance reflected back to the filter. What little error there is is swamped out by the 10 Ohm resistor. I don't know of any way to set polarity short of using instruments. Just be sure left and right are set the same way. That is really what counts. Absolute polarity set wrong just generates glitches in the frequency response. I'm not convinced the human ear can hear phase errors between bass and midrange. You can definitly hear left / right phase errors though. Al K. Quote Link to comment Share on other sites More sharing options...
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