Harris software X-over pro can estimate x-mas based on other parameters and driver size. I don't remember if Sound Easy can calculate x-mas but I can look it up tomorrow. Are this “no name” drivers?
Sound Easy will also run a distortion sweep.
I got them from a friend who buys a lot from an importer. There's usually not much, if anything, for specs. I ballparked the Xmax at 4mm and modeled it in WinISD and it didn't look bad but I really don't like guessing on this kind of thing.
I did car audio for a long time and it was never an issue because we usually built boxes for drivers that had a spec sheet or it was easy enough to get. We had Term Pro, one of Wayne Harris' older programs and it worked really well. I decided to use some drivers that were left over from a car I had, so I got the parameters, loaded them into the computer and ran the program, built the box, used the RTA with pink noise to see what the drivers were producing and did the x-overs. I had planned to use them in my basement workshop but when I listened to them, I retired the speakers I had been using for over 10 years because the ones I built sounded so good. I'm getting some long-throw 10" woofers next week and I'll be in the same position, but I may lift the dust cap on one to measure the height, although that doesn't take the distortion into account but it's a technique that has been recommended by one of the JBL engineers since the early '80s.
