Can I use an isolation stand with an isolation pad?

Getting back to the question posed by the OP for a moment the general answer is no, you should not (rpt not) use two isolation devices in series, only under special conditions. It would be like driving a car down the road with two shock absorbers connected in series to the wheels. The shock absorbers would interfere with each other and the ride would be extremely bumpy. Is is possible to construct a dual layer mass on spring isolation platform, I actually sell one, the Nirvana. But it’s tricky. The most straightforward solution for SQ would be to put cones under the stand. 

While it’s admirable that newbies support each other, it very touching 😢, this isolation spring kerfuffle is probably just a case of even a blind dog finds a bone once in a while. Instant expert syndrome. 🤗

Whoa! You are good at the back and forth. Very ouch! I might have underestimated you. 🙄

Are you channeling glubson? If so you’re doing an excellent job. Newbies have a propensity to sass their elders and want to take charge and move out. But move where? 😁 McMaster Carr - supplier to the stars ⭐️ 

I would know which springs to buy. You, I’m not so sure. I could be wrong. 

 Of, course it helps to know what you’re doing. No offense to you personally.

Springs, my friend. Especially for subwoofers as they produce very low frequencies, unlike your average full range speaker.