By now, I guess most of us have seen the ads for the 'new' Jet DC system with the baffle between the upper and lower bags/filter & bag.
Essentially, it's an upside-down bowl that's suspended just below center.
When I checked, Jet wouldn't sell the parts to modify older DCs. (That may have changed by now.)
Anyway, I ran across this article in Popular Woodworking's "Editor's Blog" that had exactly what I needed, so I began looking for a wok to use. Seeing them for 30~40 bucks kinda discouraged me, but yesterday I found one for FIVE BUCKS (!) at IKEA, so I bought it. I installed it last night. Took about half an hour (after taking at least that long to clean out the DC first... ) and it works quite well.
Prior to installing it, I had what looked like a small whirlwind in the lower bag, and had a lot of dust go to the upper bag, and then drop down onto the metal shelf between upper and lower when I shut the DC off.
Now, there's hardly any turbulence in the lower bag, and essentially nothing going up into the upper bag. The modification was CHEAP and apparently quite successful.
I didn't take any pictures of mine, but it loos exactly like the pics in the referenced article (except that my DC is a 2hp Penn State model).