View Full Version : My First Crossover Network
04-26-2009, 03:50 PM
I have just finished my impedance equalization filter and I'm not sure exactly where to take my impedance measurement to design my crossover. Are you supposed to take the measurements at the crossover frequency and if so would the following calculation be correct if i wanted to crossover at 2,000Hz for the attached impedance curves?
I will post parameters tomight
This is for the Dayton DC28F-8 1-1/8" Silk Dome Tweeter and the DA 175-8
Any other information that could help with this project would be appreciated!
Thanks for the help
04-26-2009, 06:05 PM
Impedance at the crossover frequency would be your best bet. But what a text book filter like this will not account for is the anomalies in the acoustic response especially a metal cone driver. An impedance equalization network is a good idea if you are not modeling the acoustic response but without modeling this circuit with your measured impedance it is impossible to know for sure how effective the circuit is. Plus even if you did equalize the impedance this will not account for the acoustic response issues of the drivers. Metal cone drivers rarely have flat responses and usually have significant break up regions that require you pay special attention. Plus while those components may get you to sum close to flat around the crossover point are you accounting for baffle step.
Download Jeff Bagby's PCD and load the zma files you have and create some frd files from the PE data and model your results. You can account for baffle step and model the zobel. Heck it is not likely you need impedance equalization at all if you use PCD as you can simply adjust the network values to get the summed acoustic response you want.
If you are uncomfortable learning PCD, which you should not be it is pretty straight forward, I would go steeper on the DA175 just to be sure you get the break up down to about -50db.
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