WHY SHOULD I REPAIR AND/OR UPGRADE INSTEAD OF BUYING NEW LOUDSPEAKERS?
There are a number of reasons:
SAVINGS
The box, or cabinet, is one of the most expensive and definitely, the most difficult to build components of any loudspeaker. The cabinet does not reproduce sound. It's just there to provide a specific volume of air the woofer needs to operate in. So, why spend your hard-earned dollars on replacing it if it's still in reasonably good condition?

GETTING VALUE FOR YOUR MONEY
Money spent on repairs and upgrades is used to fix or replace only critical parts that effect your listening pleasure and not on cosmetics (the box). Thus, your investment is focused entirely on improved sound and listening enjoyment.

FAMILIARITY AND FIT WITH YOUR LIVING SPACE
You are simply used to seeing a particular set of "boxes" sitting on your floor or shelf. A new box serves to distract from your listening pleasure. Also, the wood finish of your old speaker cabinets is generally superior to anything new these days and may nicely match your other furniture or decor.

WHAT IS INVOLVED IN AN UPGRADE?
The three main components of any loudspeaker are the drivers (sometimes referred to as speakers), the electronic crossover and the box. The upgrade process involves replacing only some of, or if needed, all of the critical components in the signal path. Those critical components are the drivers, the crossover, and sometimes the wire connector at the rear of the cabinet. As an option, your upgrade could also include renewing the wood finish and stiffening the cabinet to prevent resonance problems.

WHY DO DRIVERS AND/OR CROSSOVERS NEED REPAIR OR REPLACING?
One of the most common maladies of older loudspeakers is rotting of the foam surround located near the outer edge of the woofer. I can replace these. Old, paper-cone woofers can also dry out and are not as responsive in the lower, mid-bass as they once were. Sometimes tweeters loose their responsiveness and as a result the soundstage and "airiness" is lost. Most mass-produced loudspeakers are made with low quality crossover parts. Simply upgrading the crossover can sometimes make a huge improvement in the sound. Capacitors with metalized polypropylene film type or, audiophile grade film/foil designs will usually make the most improvement. Cheap woofer coils, if there are any at all, are usually metal core. Replacing them with air-core type will also improve bass response and overall crossover performance.