One of my speakers sounds like it's underwater.

[TLS Guy]

I may just throw a pair of these in there and see what happens

Waste of money. You can't swap drivers. The sensitivity is close, but that Dayton driver is breaking up before the crossover point and the porting and crossover will not be correct. If you want to use those speakers you need to recone them yourself, or pay to have them refoamed.

 

[isolar8001]

I may just throw a pair of these in there and see what happens

Bad Idea as TLSGuy has stated.

Rather than all of us shooting in the dark here...
Is/are the foam/surrounds good ?
Do they need new surrounds ? Thats easy and cheap if that's all it is.

If they are popping and breaking up with good surrounds, you need new woofers....the voice coils are blown.
Pictures of the woofers ?

 

[Gil_Pena]

Remember, keep them away from your aquarium ....

Hahahaha

 

[Gil_Pena]

Hmmm says my files are too large . Pics of course. The surrounds look very new. Almost perfect.foam.