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Small Fostex Fullrange Speaker Modifications and Tweaks


Small Fostex Fullrange Speaker Driver Modifications and Tweaks

There are many great modifications and tweaks for the smaller Fostex fullrange speaker drivers. Some examples of the simple and inexpensive modifications which can be made to these speaker drivers are described below. For those who don't want to permanently alter the fullrange speaker driver, the modifications are reversible. The modifications and tweaks are generally focused around the idea that the light-weight stamped steel chassis can "ring". These modifications and tweaks are suitable for the Fostex (FE83En, FE103En, FE126En, FF85WK, FF105WK, FF125WK) drivers and can likely be applied to similar small speaker drivers that also use a stamped steel chassis. For the larger Fostex fullrange drivers see the Fostex FE206E / FE206En driver modifications and tweaks page.

duct seal putty

Photograph 1: Duct seal putty.

Fill Gap between Chassis and Motor with Duct Seal Putty

Fill the open gap between the motor (magnet) and the chassis (frame) using duct seal. The duct seal will help dampen against ringing. You should be able to find the duct seal in the electrical section of your hardware store and a block should be under $5 (Photograph 1). Electrical duct seal is a non-hardening sealant that adheres to metal, masonry, wood or plastic. Photograph 2 shows an example of using duct seal to dampen the open gap between the motor and the chassis. Check the improvement for yourself by tapping the speaker chassis with a screw-driver before and after the modifications and listen to how much quicker the chassis ringing fades away.

Use Duct seal putty to fill gap between speaker motor and chassis

Photograph 2: Use Duct seal putty to fill gap between speaker motor and chassis.

Rubber Cement / Adhesive used to hold Felt on FE103En

Photograph 3: Rubber Cement / Adhesive used to hold Felt on FE103En.

Use Sound Absorbing Material on Large Reflective Surfaces

It is always a good idea to cover the magnet with sound absorbant material. This is to limit the reflection of sound waves in the enclsoure. Ideally you will want to use a nice thick material that will effectively absorb sound waves. In this example a 50/50 cotton/acrylic felt, 3 mm thick is used. To make a nice thick pad, use rubber cement and glue two or three felt pieces together (Photographs 3 and 4).

Modified and tweaked Fostex FE103En fullrange speaker driver

Photograph 4: Modified and tweaked Fostex FE103En fullrange speaker driver.


Fostex Fullrange Speaker Links