For years, I wanted to design my own speakers, but didn't understand the intricacies that went into it. For all I knew, you bought a 2500 hz crossover from parts express, picked a woofer and tweeter that looked cool and went at it. It wasn't until i really got into DIY speaker building that I understood how wrong I was. Thankfully, Jeff Bagby came up with a great free to use program that can help us all out. My goal here is to help the DIY community along by helping teach the program to the best of my abilities. If anyone has any suggestions or questions, let me know, I'll see if I can help. Since, I personally am a visual learner, I'm creating a video tutorial series on this program. The first one, I just completed which shows you how to import FRD and ZMA files, as well as where to locate them. And how to use SPL Copy, if all else fails. I also help troubleshoot if your frd files are not importing properly. Here are the programs you will need: Passive Croosver Designer: Jeff Bagby's Software Page SPL Copy: SPL Copy - Speaker Frequency Response Automatic Trace Tool Here's a link to a playlist which contains all the videos in the series: Playlist: How to Design a Crossover - Passive...Watch this playlist on YouTube I currently have 6 videos in the series, I hope you enjoy and learn something. Please let me know if there is something else you want to learn. I'll try to post it when I can.