How to Waterproof Your Speaker's Woofer Cone

We waterproof our speaker's woofer cone by applying some Varthane water-based wood finish. Check out this section of this Instructable , where I got the idea of waterproofing: www.instructab...

[@rickbrandtstarman1724]

I am not confused from the procedure you do but doesn't using a Urethane mess up the good bass and other music notes of the speaker? I don't know, never did this myself. I would think since it dries hard, like when protecting a wood surface, it would not allow the speaker to do it's job...no? am I wrong here or what? I have some speakers with 6" woofers I use outside a lot and always try to cover them at night. I was thinking of spraying them with a couple coats of fabric waterproofing spray like we use on camp equipment. Any thoughts on that?

[@omarshishani5899]

I didn't notice any difference in sound after I applied the urethane. It definitely did not break the speaker. It doesn't dry so hard that the whole thing becomes completely solid. A couple coats is still flexible. I would think probably many coats is still flexible.
If you're concerned you can try it on a cheaper speaker you have, or go buy a small cheap used speaker and test it on that.