Copper vs Aluminum

Copper versus Aluminum coil windings..

The performance difference between copper and aluminum coil windings lies in the physical and resistance differences in the two materials. Copper is the more efficient conductor, able to transmit the same current with less cross section area. Aluminum requires more cross section area to do the same job...

Aluminum has lower mass than copper giving the ability to move the same current, albeit through a larger conductor than copper, but with an overall reduction in mass...

The larger surface area of aluminum can have an advantage in a voice coil when it comes to the length of the coil windings. An aluminum coil of the same impedance as copper will end up with a longer winding length, increasing the Xmax number...

Some system designs may benefit from the longer Xmax if the system uses extremely long excursions, as may the case is competition vehicles making high distortion 2 second SPL runs. The longer coil windings keep more turns of wire in the magnet gap at high excursion...

The aluminum wire, with its larger cross section area, is not as efficient as copper. A copper wire coil will pack more turns of wire into the magnet gap and results in higher energy over the operating Xmax of the coil. Well designed enclosures usually give better performance with the more efficient copper windings in both sound quality and output...

The power handling differences between copper and aluminum are negligible IF both wires are using the same coatings and same adhesives systems. Aluminum will have more surface area to dissipate heat, but takes more power to reach the higher efficiency of the copper coil, in subwoofer applications. In midrange/tweeter applications, the lighter aluminum wire can have significant impact on high frequency performance where moving mass dominates...

In 95% of the applications we see, the copper coils are the way to go...