The back of the drivers really has to be treated in some fashion due to the large size of the magnet surface and the shallowness of the first (compression) chamber in the horn cabinet. To the stamped speaker chassis I have added bituminous aluminium foil to dampen the Fostex FE206En drivers frame (Photograph 3).
Photograph 2: Fostex FE206En Fullrange Speaker Drivers
For more tips and ideas see the Fostex FE206En fullrange speaker driver tweaks and modifications page.
Note that there are many tweaks and modifications that can be made to improve the performance from the Fostex FE206En drivers. Better yet would be to cover the magnet with a more sound absorbing material like felt or wool. The magnet of the FE206En driver is extremely large so it is also covered with bitumanized aluminium foil tape (Photograph 2) to help reduce sound reflections from the back of the speaker box.
The photographs below show the Fostex FE206En fullrange speaker drivers used with the rear-loaded horn speaker cabinets.
For the full dimensions of the Back-Loaded Horn speaker enclosure plan and the cutting plan see the Fostex FE206En datasheet - (PDF 488kB).įigure 1: Fostex FE206En Back-Loaded Horn Speaker Enclosure Plan Figure 1 below shows the speaker box plan from the datasheet. The back-loaded horn speaker enclosure plan is from the FE206En datasheet that was included with the Fostex FE206En driver. Sound absorbing material should be used directly behind the driver and also at the mouth of the horn to smooth out the frequency response.įostex FE206En Back-Loaded Horn Speaker Box Plan For "tighter" sound reproduction, you can reduce the interior volume of the horn speaker cabinet using fill material. Back-loaded horn speaker enclosures are generally amongst the most efficient enclosure systems and respond well to the subtlest components of music signals. The remainder of sound spectrum (mid and high-frequency ranges) is radiated directly from the front wave produced by the speaker driver. The back-loaded horn speaker enclosure operates by developing the bass response using the back wave from the speaker driver and an expanding horn section. The difference however is that back-loaded horn (BLH) speaker enclosures make among the most efficient use of the back wave from the speaker driver. The back-loaded or rear-loaded horn loudspeaker system is like bass-reflex and double bass-reflex speaker types in that the sound radiated from the back of speaker transducer is utilized to enhance the bass response. Photograph 1: Fostex FE206En Back-Loaded Horn Loudspeaker Enclosure Being impressed with the great sound from the smaller double bass-reflex speaker boxes I decided I wanted to get horny and have a pair of the large back-loaded horn loudspeaker enclosures made up. The speaker enclosure plans for the double bass-reflex cabinets were provided with the FE206En driver documentation which also included speaker cabinet plans for a large back-loaded horn speaker enclosure. For their size and cost the Fostex FE206En double bass-reflex speakers really sound great. Previously I have written about the 8" Fostex FE206En fullrange drivers and two pairs of Fostex FE206En double bass-reflex speakers with front firing ports. Fostex FE206En Back-Loaded Horn Loudspeakers