Bass Reflex Bookshelf Speakers

Until recently my desktop computer has always shared a room with a Hi-Fi setup so there has never been a need for using decent speakers with the computer. When the desktop computer was moved into it’s own room (with no HiFi) I quickly realized that good speakers were now required for decent quality music playback. I had been using some low cost Radio Shack speakers with an inexpensive Tri path based amplifier and I was really itching for an upgrade.
The speakers would be used primarily for background music while working on the computer and also for watching videos, gaming and some recording. As the speakers would be used on a desk, the size needed to be restricted to a small bookshelf / monitor sized speaker. Over the past several years I have grown quite fond of the sound from the various Fostex full range speaker drivers.
A full range driver can be quite appealing as it offers point source sound with no crossover to mess with the phase so you also get great imaging. The lack of a crossover reduces the material costs and also greatly simplifies the design and construction of the speaker. For these speakers I decided to try out the Fostex FE103En fullrange driver ($44US, Apr 2013) in the “recommended” bass reflex enclosure from the datasheet. The bass reflex loudspeaker enclosure has a volume of 6 Liters (L) and is tuned to 95 Hz.
Bass Reflex Bookshelf Speakers
A bass reflex (ported) speaker enclosure improves the low frequency response of the loudspeaker system by transmitting the energy from the rear diaphragm of the driver and the rear baffle through a tuned port to the listener. These phase-inverting type of loudspeaker enclosures are most commonly referred to as vented, ported or bass-reflex. The interior of the speaker boxes are typically lined with a thick damping material or stuffed with loose synthetic or wool fill. The fill is used to dampen the rear wave from the driver and minimize standing waves and reflections within the enclosure. The bass reflex type of loudspeaker enclosure is among the most common type used as it lends itself well to small size and reasonable bass output.

Fostex FE103En Recommended Bass Reflex Speaker Enclosure Plans

The loudspeaker box details are from the Fostex FE103En datasheet and recommended enclosure plans and are shown below with some additional build notes. The datasheet notes the enclosure volume as 6 L and tuned to 95 Hz. From the dimensions the gross volume is calculated to be 6.9 L and the box tuning frequency to be about 97 Hz.

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