All of the active parts of a loudspeaker are held together by a part called the basket. Sometimes called a frame or a chassis, the speaker basket is connected to both the magnet assembly and cone assembly. The permanent magnet–meaning it has a fixed polarity–interacts with an electromagnet created in the speaker’s voice coil. The speaker cone is a thin, semi-rigid membrane that when attached to the voice coil, vibrates and acoustically couples to the air to produce sound. The magnet and cone/coil assembly are held together by the basket, providing an attachment flange for mounting the speaker to the baffle or the product into which the speaker goes.
Many companies use the basket as an opportunity to brand their loudspeaker with colors in their logo or brand guidelines. This is by no means necessary, however the perception of quality of a loudspeaker can often be influenced by the basket’s material, finish, fabrication quality , and even paint color.
Speaker Basket Materials
The most common material used for the speaker basket is stamped steel–a flat piece of sheet metal that is put into a die and pressed into the proper shape. A quality stamped steel basket is rugged, durable, and doesn't bend or twist easily. It’s painted or plated to prevent corrosion and rust.
Another material that's commonly used for a loudspeaker basket is cast aluminum. Cast aluminum, like stamped steel, is rugged and durable. It too can be painted, and is considered a higher end basket material among the professional and home audio industry. Cast aluminum baskets are made by melting aluminum and pouring it into a mold.
Impact on Overall Speaker Design
Generally, cast aluminum speaker baskets are used on more expensive speakers and they generally cost more than stamped steel.. Making either option stronger can be accomplished by either increasing the thickness of the metal used or adding reinforcement struts or ribs. High quality speakers can be made from either material.
While baskets play a critical role in the assembly and durability of a loudspeaker, they are often assessed from a quality standpoint on visuals alone. As mentioned earlier, this is why speaker manufacturers often choose to differentiate their baskets by adding branded colors or finishes to make the appearance of the loudspeaker more unique. To learn more about the inner workings of loudspeakers, download our Loudspeaker 101 Guide.