So basically my mics are crap. Im not sure what my mics are to honest, I was given them a few years ago. Heres a link to a picture of them if that helps.
This doesn't answer your bass roll off question, but...
The picture is fuzzy, but they kind of look like my Core Sound low cost binaurals. I've made some great recordings, and some not so great recordings, with my CSB's. I wouldn't call them "crap", if that is what you have. They do well in the right situation, and I've never used the bass roll off on mine. I remove bass in post, if needed.
On closer inspection of your post, I'm not sure you would be plugging CSB's into a SP-SPSB-8. Regardless, they look like Panasonic WM60-ish caps. Again, not total "crap" if the stars align for you.
I've heard recordings with church mics, and know two local church audio mic users, and you would be pleased with them if you feel like a change.
--Michael