A micro subwoofer is a small version of the large, car trunk-sized subwoofer speaker enclosures commonly sold for loud, booming bass sounds. Normally measuring approximately 12 inches (30.5 cm) square, the micro subwoofer enclosure design offers adequate low frequency sounds without sacrificing space in a home theater system. These speaker types are typically marketed as an accompaniment to a complete set of small, matched speakers.
The actual micro subwoofer speaker size is usually about 8 inches (20 cm) in diameter. This speaker can be enclosed in a number of different supportive boxes, but most smaller subwoofers use ported designs for the best sound output. In this design, a tubular port connects the internal speaker with the outside air, producing strong sound waves that bounce within the enclosure and eventually down the long port. As a result, the emanating bass is a solid boom that creates forceful vibrations.
Port orientation depends upon the owner's sound preferences. Many subwoofer enclosures for home theater systems use a port directed downward, toward the floor. The emanating bass frequencies strike the floor, allowing the vibration to move outward as a subtle sound effect. Changing the port direction to face the listeners creates an entirely different sound. Sound waves enter the listeners' ears directly for a strong, booming effect.
Small apartment sound systems are commonly enhanced with a micro subwoofer. Experts suggest a maximum space of approximately 200 square feet (18.5 square meters) for the best sound coverage. A larger coverage area will require multiple micro subwoofers or larger speakers. The emanating bass becomes lost within a larger room since the sound waves have a longer distance to travel from the small speaker shape. Smaller rooms allow the bass to reflect off of surrounding walls for increasing low frequency response.
Placement of the subwoofer directly affects the sound output. Hiding the subwoofer behind a sofa lowers the sound impact, in fact. In contrast, the owner could locate the micro subwoofer immediately in front of the listeners for the loudest and most solid bass effect.
Micro subwoofer design requires the speaker to have a powered amplifier. Small speaker sizes do not produce the loudest sound without electronic component assistance. These specialized speakers commonly have an amplifier built into the enclosure, matching the subwoofer's power needs exactly with the amplifier's electronic components. Improperly matched subwoofer and amplifier combinations can result in damaged speakers and poor quality sound output.