Hi-fi speaker repair

A dynamic driver is a simple but precise construction: cone, outer surround, spider, voice coil in the magnet gap, and flexible tinsel leads. Each element ages in its own way. Foam surrounds decay chemically within 15–25 years — a property of the material, not a consequence of use. Rubber surrounds harden and crack more slowly. The voice coil burns out from sustained overload or a clipped signal, while tinsel leads wear through from decades of cone movement.

We always refoam with voice-coil recentring: after stripping the remains of the old surround and adhesive, the new surround is glued so the coil moves freely in the magnet gap without rubbing — verified by listening test and measurement before the driver goes back into the cabinet. For tweeters we most often replace the diaphragm complete with its coil — for many brands these are available as original spare parts. Tinsel leads and terminal connections are re-soldered, oxidised contacts restored.

The crossover splits the signal between woofer and tweeter, and its electrolytic capacitors drift in value over time — the crossover point shifts and the sound turns dull or harsh even though every driver technically works. After 25–40 years this is the norm, not the exception. We measure the components and replace aged capacitors with quality film equivalents (Mundorf, Jantzen and others), keeping the original schematic values — the goal is to restore the factory sound, not to "improve" it. Resistors, inductors and solder joints are checked at the same time.

The economics are simple: repairing quality passive speakers almost always pays off — an equivalent new pair costs many times more than the repair, and a good cabinet with good drivers does not go out of date. The exception is cheap packaged-set speakers and plastic satellites, where we say plainly that buying new makes more sense. That assessment comes with the diagnostics, before any work begins.