During the seventies and eighties, either planned obsolescense, poor engineering, or shortsightedness caused speaker manufacterers to use a type of rubber surround for drivers that deteriorate with age.
Perhaps you have a pair of speakers that show the classic grainy, dirty looking speaker surrounds or maybe even have holes in them already. I got a pair of old Advent Heritage speakers from a guy for free because the surrounds were shot. The previous owner tried using silicone caulk to stave off the inevitable to no avail
For about ten bucks a driver, you can replace the foam surrounds if you have some patience and determination. There was a time when the quality of a manufacturers equipment was what determined their success, rather than the amount of money they spend on advertising. While those days are past, many of this aging Hi fi equipment can be gotten off craiglist or freecycle for a song. At best, they are ready to go with a little dusting. Sometimes, however, the drivers need to be refoamed.
The foam surround kits are not inexpensive so make sure you are getting a decent pair of speakers to begin with. Also the paper cones should move freely and they should still make sound when played. All the drivers should play. If they have been energized a lot with the surrounds damaged, the voice coil could be abraided away, shorted out, etc. Those should be avoided because I don’t think that’s an easy fix. Today we are working on a pair of Advent Heritage speakers. They are not the classic Advents and were produced after Jensen bought the company and ruined it. However these speakers, despite, their shortfalls, sound really good to my ears. The cabinets are pecan and clean up really well.
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