Cuttin-Edge, On-the-Spot Reporting

Fiberglass Fabricating

Since JL Audio produces products for home, mobile, and marine use -- sometimes needing extremely complex cabinet shapes -- fiberglass fabrication and finishing are key to their manufacturing capability. Fiberglass is also used for some of their top-of-the-line products. We were fortunate enough to see the fiberglass-based Gotham subwoofers in various states of manufacture. The Gotham g213, which retails for $12,000, is JL Audio's best and is considered to be among the state-of-the-art in the subwoofer marketplace.

JL Audio

JL Audio's senior training director, Stephen Turrisi, showed us the large areas of the factory dedicated to fiberglass production.


Before the Gotham comes the mold used to form the cabinet. There are actually four molds used for each enclosure, this due to the Resin-Transfer Molding (RTA) technique the company uses. RTA starts with . . .

JL Audio

. . . preparing the molds with raw fiberglass. From here, a second mold is placed on top, and resin is then literally sucked into every crevice while air is vacuumed out. This process produces a cabinet that's said to be much stronger and stiffer than MDF.

JL Audio

Once the cabinet is formed and dried, Gothams go through various stages of sanding and milling, then . . .

JL Audio

. . . painting. Painting is done in-house in an automotive-style paint booth.

JL Audio

Stephen Turrisi points out several of the key design features of the Gotham shown above in mid-production. Of note are the internal braces, which are literally part of the molded cabinet walls -- it's all one piece!

JL Audio

It's in the final stages of sanding and then polishing that the beauty of the finished product begins to show. Note the orange conductive paint on the interior that shields from electromagnetic interference.


What starts off in manufacturing as a rather ugly duckling winds up being a state-of-the-art-finished showpiece with impeccable fit 'n' finish. This finished Gotham has also been through a full battery of quality-control testing that includes rather loud acoustic measurements.

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