Hi,

I have an old pair of boxy speakers I'm gonna spruce up (veneer, add inner bracing, etc).

The woofers are paper coned, and I've seen a lot of people coating theirs with Mod-Podge, acrylic medium, Dammar varnich, Polycrylic, PVA glue, etc.

I was assuming that you would only paint the visible paper part of the speaker cone, and avoid the dustcap. But now I'm not sure about this. Does sound come through the dustcap? Now that I think about it, there are a lot of speakers that have plastic, mylar, or aluminum dustcaps...which no sound would come through.

Just wondering because my dustcaps seem to be made of some porous material. There's a fine, tightly-woven look to it. Didn't know if it would be wrong to put a coating over it.

Thanks!

Hi
the dustcap is a part of the oscillating assembly, so it also produces a part of the sound. Another task of the dust cap is to stabilize/damp the diaphragm.

I would coat the cap also, but be aware thet the total moving mass will increase, resonance frequency will decrease and the overall tuning of the cabinet/driver system will change. If you use a bass reflex system, maybe it will no longer work as designed.

I did not read carefully enough. Can you see the central pole piece through the cap? If it is an open (permeable for air) mesh, it would be better to keep it open, don't add any coating to it

You post sound a bit as though you are laboring under a mis-impression. Sound does not 'come through' any part of a speaker driver. The cone (or other membrane in a different design) produces the sound by moving air.