The foam perimeter on this vintage Advent speaker has completely deteriorated.
The foam perimeter on bass stereo speaker drivers, also known as woofers, is a flexible material that allows the paper or plastic cone to move back and forth. This motion is the result of the push that occurs on this material from the impact of the sound waves. Because this motion is nearly constant (depending on the amount of bass in a given recording) and the material is very flimsy, over time the perimeter can develop tears. According to the Speaker Doctor, a speaker repair service, this occurs because "the poly-foam suspension or surround on a woofer or mid range speaker will 'dry rot' or disintegrate." Perimeter tears cause an annoying static.
It is not necessary to replace the entire speaker when tears occur. With exceptionally good speakers, the drivers are made of quality materials and are exceptionally designed, which results in high-fidelity sound. Fixing the perimeter will preserve that quality performance.
Instructions
1. Order a foam edge repair kit, preferably one designed especially for your particular make and model of speaker. A number of online speaker specialty sites sell repair kits with material designed to replace the foam edge on particular speakers. Attempts to spot repair these tears with glue or patches are fruitless since others will develop from the overall and inevitable continued deterioration of the perimeter.
2. Remove the cloth grill from the front of the speaker cabinet. Most of these are connected to the cabinet with Velcro attachments. Remove the speaker driver from the speaker cabinet with a screwdriver. Carefully pull the driver away from the cabinet and take note of how the speaker wires are connected. Carefully slide these wires off the connector posts and place the speaker on a workbench or table.
3. Carefully remove what remains of the foam edge that surrounds the speaker cone. It will probably crumble or flake away without much effort on your part, but you don't want to cause tears or abrasions to the cone by this action.
4. Determine the size of the foam surround needed for your particular speaker. According to Speakerworks.com, this measurement is based on the diameters of the speaker cone and that of the edge of the hole that parallels the cone. The space between these two diameters is the space that is filled by the foam perimeter. The perimeter material should be wide enough to allow for an overlap on each edge. Repair kits are available through online, speaker supply stores specifically made for most high-quality, vintage speakers made by companies like Advent and JBL. Get a kit for your particular speaker if it is available, and there will be no need to make this measurement at all.
5. Follow the instructions included with the repair kit. These kits usually include presized foam perimeter material, glue specifically designed for this purpose and a glue brush. For quality, vintage speaker repairs, do not eschew the kit and scavenge these materials from your household. Prices for these kits range from about $30 to $60, depending on the speaker make and model. Much research has gone into a quality, name-brand speakers as far a design and materials, and custom kits are well-worth the cost.
6. Once the glue is dry, attach the speaker wires to the correct connector posts and the driver to the cabinet. Replace the cloth grill. Now you once again can enjoy those LPs or CDs through your high-fidelity sound system.
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