http://www.studiosoundelectronics.com/speakerkits.htm
:I think the front grille cover pulls off. The speakers are mounted from the front. I bet it's not anything to do with the cross over network, but speaker deteriorated foam surrounds. Here is a link in case you need it for a fix-it-yourself kit.
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:http://www.studiosoundelectronics.com/speakerkits.htm
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