Normally don't stuff a TH, just add some damping where the driver(s) are such as open cell foam or OC 703 panels. If a regular sub.
Well, the five dollar pillow at Walmart cannot be beat…. There are obviously a couple things that are a little bit more effective but they’re dramatically more expensive and so there’s no point if you’ve got a whole transmission line to work with you got all kinds of room to take care of all kinds of problems on the cheap.. especially if you fold its strategically and enter at the first fold and then take advantage of the ability to stuff that whole area and use horn responses your initial guide. It would appear they dontneed more than exactly what Gm suggested.(go figure👍🏼 wiseman)