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Fostex FE108 Sigma Speaker Driver


Fostex FE108 Sigma Fullrange Speaker Driver

Note - this driver has been discontinued and is no longer being produced. The Fostex FE108 Sigma (FE108S) is a 100 mm (4") full-range driver. The driver is well built and like most Fostex units, it sounds excellent. Unlike many of the other full-range Fostex drivers which use a stamped frame, the FE108 Sigma is constructed on a cast frame. The FE108 Sigma has a low Q and thus, it is best suited in a horn enclosure. The FE108 Sigma has since been replaced by Fostex with the newer FE108E Sigma (FE108ES).

Fostex FE108 Sigma (FE108S)
Fostex FE108 Sigma Fullrange Driver

The plan for these drivers is to use them in a backloaded horn enclosure. I have not decided which horn enclosure I will use, but I am leaning towards The Frugal-Horn Project.


T/S Parameters - Fostex FE108 Sigma

The Thiele/Small Parameters for the Fostex FE108 Sigma driver provided by Foxtex are shown in the table below.

 Parameter   Fostex 
Fs 80 Hz
Vas 7.07 L
Qts 0.2
Qes 0.22
Qms 2.21
Re 6.5 Ohms
Le n/a
SPL 92 dB

T/S Parameters - Fostex FE108 Sigma Fullrange Driver

Datasheet and Enclosure Plans - FE108 Sigma


Project Links - Fostex FE108 Sigma