Let's see, Par is a parabolic horn model. As it is more of an oval it is a better fit for the normally rectangle builds that people do. I haven't contacted Bjørn or McBean yet to find out the specifics, as I have a few application questions about the assumptions they made as no new width parameter was added
, because all the horns I designed didn't change at all when switching over. As long as you are staying with a simple single non-exponential flare it seems to be the way to go. It makes a minor difference here, but I do not know how long you tweaked this one.
I always allow HR to calculate the parameters. For the life of me I can't remember why you need to do it that way right now, but you do need to do it that way. I know McBean has pointed it out several times over the years. You put in the SD, Re, and Le then double click Cms, Mmd, Bl, and Rms to input Vas, Fs, Qes, and Qms.
The TC factory parameters seem off a little because the Mmd ends up larger than the given Mms, and it should be less.
Fs = 1/(2p * SQRT(Cms*Mms))
Mmd = (Added Mass)/ (fs/(Mass fs))^2 - 1
Cms = 1 / (2pfs)^2 * Mmd
Vas = (Cms * 1.184 kg/m3 * 346.1 m/s * Sd^2)*1000__at 25C
so either the supplied Fs, or Vas is off some. Sorry too much info.
Also I am not really good with the smaller horns. I can help with folding, but not too much with design. My first pass with this driver ended up twice the size with less compression, a flatter curve, and more sensitivity, but it was still on the smallish side to me. I could live with it though, reactance annulling finally kicked in.
I ran the driver through my Leach spread sheet, and it didn't work quite right. Normally, I can design a horn for the driver, and then use that info to input the horn and let the program tell me the driver parameters it needs, and they match up almost if not exactly. This one didn't.
I'll take another pass later on.
You also have a lot of Vtc there. Is that because of the surround? Is it that huge?