Sealing dust covers

[DKinYORKpa]

I found 2 answers to this researching past posts. After resealing the pleated surrounds on my AR 1 cabinets, the one passes the "push-in test". The other one doesn't. On that one, there is a domed dust cover made from the same material as the surround. If I lay a small circular piece of paper on the dust cover, when I push in on the cone, air flutters the paper. Should I seal the cover? On the good cabinet, there is a slightly domed felt cover.

[Carlspeak]

Some woofer designers use a screen dust cap to help cool the voice coil. Vented pole pieces are another way to vent air out thru the back. Another way is to use a felted dust cap to allow some air leakage in a controlled manner. Lastly, some use a perforated voice coil (small holes around the VC near the top). Those are intended (usually) to also vent the VC by instead allowing air to escape during the cone's in and out motion. The escaping air comes out of the VC underneath the spider which is porous and thus vents thru the spider. I can't say with any certainty that for the perforated VC type situation that the dust cap is always sealed. I do know that AR did use the perforated VC cooling method in their 12 inch woofers. Maybe a historian or two can shed some light on when that practice started.

I suggest you shine a strong (LED) light down thru the dust cap while lifting the cone. Look for holes perforated around the voice coil near the top.  If you are still working with your AR1 woofers, I'd be surprised if a woofer that vintage would have the VC perforated. Then again, that woofer may be a factory replacement (somewhat more modern). 

I'll stop now. Too much speculating...

[DKinYORKpa]

Well, I coated the dust cap and the woofer now moves like the other one.