The latest update is finally done and available to download. The changes are primarily in the user interface and off-axis calculations and plotting.
First, the GUI. The screens seemed too cluttered to me with too many textboxes. The screens now have group boxes that enclose sets of controls rather than having a big text box above them to say what they are. This to me makes it easier to see what controls are for each function and makes it easier to pick them out. They are still laid out in roughly the same pattern, though, so it shouldn't be confusing to anyone who has used either previous versions of WinPCD or Jeff's PCD.
There are several changes to the polar section. The original scheme for off-axis plot changes did not maintain the same off-axis distance, the z-axis remained constant. This limited the off-axis angle and caused other problems. The new scheme maintains the same distance with angle (a vector). You can now examine all off-axis points from -90 to +90 degrees vertically and horizontally. In addition, new graphs are available for them. Previously you could only see the current off-axis plot as the main curve. The new plots appear in new windows, one for horizontal spanning and one for vertical spanning. When you select one of them, the program automatically calculates all curves from -90 to +90 degrees in 5 degree increments, then displays them all in the new window. Options are available to selectively display only those curves that you want to see, such as only every 15 or 30 degrees on the positive side or one the negative side. Every 5 degrees is really cluttered.
One thing to be aware of when using them. If you have changed an axis from 0 degrees to, for example, 45 degrees in the horizontal setting, then when you call up the vertical off-axis window what you will see is -90 to +90 degrees with the horizontal setting at 45 degrees. What this does is let you see the off-axis at any vertical or horizontal curve on the selected plane. I know this seems confusing at first, but it's not different than looking at the vertical response at 0 degrees horizontal, directly in front. If you select the horizontal to be 45 degrees, your simply looking at the vertical response at 45 degrees to the side.
If you have the vertical set to something like 5 degrees and select the horizontal plots, you'll see what it's like to walk around the system with you ears at a 5 degree angle. This won't change much for a symmetric system, the only change for this will be from relative acoustic offset of drivers if they are not aligned (most systems).
Of course this does not account for diffraction, WinPCD is currently only for the crossover, not diffraction. That may/may not be implemented, it's a big task and I'm not sure I'll ever take that time.
The last change is the addition of driver directionality. It's optional and can be turned on/off with the push of a mouse key on a button. The off-axis plots can be compared. You disable the DI and display the off-axis changes due only to the crossover. Enable the DI and display a new plot and you can compare the difference with DI included. The DI is at the moment only the Bessel function for driver diameter, but I hope to do some fine tuning over time to try to get it more accurate. Don't expect it soon, though.