Woofer distortion

[Macpibe]

Hi,
I changed the foam surround of my Infinity RS6000 (an acoustic suspension design) 10” polypropylene woofers.
I don’t remove the dust cups and center the dome with shims, but it’s seems to be centered…
Also, I paint the (deteriorated) dust cups with a solution of water and vinylic glue.
When I try those speakers in the sealed enclosure, I can hear a distortion, more in the fast attack of a bass…
I make a mistake to paint the dust caps? Must the dust caps be “vented” with air flow thought this? Or maybe the dome won’t be fully centered whithout the “shim” metod?
Many thanks for your opinions.

[lineup]

In a sealed box I guess you will have to let a little air leak.

We see many times that high end midrange woofers
have a very little hole.

Like somebody has stick a NEEDLE into it.

So I guess you can take NEEDLE with diameter < 1 milllimeter (mm)
and stick it through dust cap.

One tiny small hole .. that's it