FOSTEX FE127E SEALED BIPOLE SPEAKER
I constructed a pair of small tower sealed bipole speakers using the 4.5" Fostex FE127E fullrange driver. The design was based on Gio's DIY Sealed Bipole Speaker Project with Fostex FE127E.
I elected to go with a bipole enclosure since it eliminates the need for a power grabbing BSC (baffle step compensation) circuit. Also, my new modded Sonic Impact T-Amps are designed for bi-amping. A sealed bipole enclosure also has the advantage of improving the soundstage for a small penalty on the separation, which is ok with the kind of music I play. I wanted to do the sealed enclosure since this would improve the midrange and the bass will be tighter. Even on a ported enclosure, the Fostex FE127E drivers do not provide great bass extension, so I still would need a subwoofer. In my opinion, porting the enclosure does not offer any advantage.
The internal dimensions are exactly the same, same driver placement, same driver, except the construction sequence is different. On Gio's construction, he started with the speaker sides and he glued the rear baffle last. On my construction, I glued the front and rear baffle first and the sides last (this has something to do with the finish I wanted). So basically, it is the same design as Gio's Sealed Bipole Speaker Project with Fostex FE127E.
The baffles are 3/4" MDF that will be painted black and the sides of the speakers are solid narra. Photograph 01 shows the Narra slabs being planed. The narra was left over from our kitchen cabinets.
Photograph 01: Solid Narra being Planed
That baffles are constructed using 3/4" MDF, shown in Photograph 02.
Photograph 02: MDF baffles
Photograph 03 shows the baffles glued and screwed to the braces. Note the chamfer behind the driver which was created with a router to give the drivers some room to breathe.
Photograph 03: Enclosure Construction
Finally, the four Fostex FE127E drivers arrive. My dog is trying to help so we can finish early. She would love to listen to Diana Krall and Lee Retinour on the new Fostex speakers!
Photograph 04: Fostex FE127E Full-range Drivers
A dry fit of the Sealed bipolar speakers with the Fostex FE127E drivers are shown in Photograph 05.
Photograph 05: Sealed Bipolar Speakers with Fostex FE127E
I connected the unfinished speakers (without the damping materials) to my two Sonic Impact T-Amps. The sound is a bit brilliant and forward. Fostex users have said that break-in time for the drivers is at least 100 hours. Compared to my AR Status 40, these DIY Fostex speakers without the break-in already sound better! Bass is tighter, but of course, you need a subwoofer for frequency lower than 80Hz.
They sound great and the vocals are to die for!
I do not have the speakers anymore, my brother begged me for them! I gave them to him since I can easily build another pair. Anyway, I have already placed an order for another set of Fostex FE127E drivers!