digjr Posted September 4, 2003 Share Posted September 4, 2003 I have a question for any and all about using my AK-3's in my 12" cornerhorns. The woofers that I am using are K-22-EF's and are 8 ohm. The K-33's were 4 ohm. What changes should be made to the crossovers? Thanks in advance for the input. Don Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted September 5, 2003 Share Posted September 5, 2003 Hello Don, Since you have had close to 30 views and not a single response I thought I would try and get the ball rolling for you. The difference in Ohm load I do not think will alter the cutoff frequency but it will change the slope. For example it may be a 12db slope with an 8 Ohm driver, but if you use a 4 Ohm driver it may reduce it to a 6db slope above and below the crossover point as determined by the 100 uf capacitor and the 4mh coil that is used in the woofer section of the AK-3. Others feel free to chime in if I am not correct. Did you verify the actual impedance of the K-33 and K-22 with a multimeter? An 8 Ohm driver will have an RE: of around 6.5 Ohms and a 4 Ohm driver will be around 3.5 ohms. How did it perform sonically? Have you tried it? Using a frequency sweep CD would indicate the actual frequencies where it weak or strong. The Bass Mechanix CD could help you identify this. Let us know how you make out. On another note are you going to attempt an Academy? For someone of your skills it probably would not even present a challenge for you. The need and desire for people to have one is indeed real. Since you did not have luck selling the scaled down Khorns on eBay nor the Belle's I believe, I think the Academy would be a worthwhile project. Quote Link to comment Share on other sites More sharing options...
JohnA Posted September 6, 2003 Share Posted September 6, 2003 Changing the impedance by 2 changes the crossover frequency by 2, but I can't remember which way a low pass filter goes. However, the K-33, while a 4 ohm driver, behaves as a 6 ohm driver in a La Scala, Belle, or K-horn bass horn. If I were you, I'd calculate the corssover components using 12 ohms for the K-22-EF in a bass horn. I like to use http://www.carstereo.com/help2/Articles.cfm for crossover calculations. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted September 6, 2003 Share Posted September 6, 2003 Hi Guys, The general rule for impedance-scaling filters is to multiply the cap values by the ratio of change and divide the inductors by the ratio. For example. 2 mHy inductor in an 8 Ohm filter becomes 1 mHy in a 4 Ohm filter. A 40 uF cap becomes 80 uFd in a 4 Ohm filter. Be advised that this is probably NOT the entire story! What you really need to do is evaluate the entire speaker and design an entirely new network! Al K. Quote Link to comment Share on other sites More sharing options...
digjr Posted September 7, 2003 Author Share Posted September 7, 2003 Thank you guys for the response. I have no means to redesign a crossover, no equipment and an admitted lack of expertise on the subject. How should I get started on such a task? What is needed? (besides help!) I am going to hook up what I have and see how it sounds. Any help or direction will be appreciated. Frzn, I will look into the Academy, it looks like a nice project! I'll keep you posted Don Quote Link to comment Share on other sites More sharing options...
formica Posted September 7, 2003 Share Posted September 7, 2003 Don... I think Frzninvt brings up a good point about the current popularity of the academy as well as any other "heritage" centre channel. As people move their heritage to HT there isn't alot of choice out there. Afterall that is the same thing that pushed me to buy that extra set of heresys... Centre channels are also a little smaller to ship, so not a bad thing... Later... Rob Quote Link to comment Share on other sites More sharing options...
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