Unlike an acoustic suspension speaker that uses a sealed enclosure, a bass reflex speaker includes a port (a hole in the box tuned to a specific frequency) or bass radiator (often referred to as a "drone cone") to produce more bass output in a tuned frequency range.

With a bass reflex design, efficiency is better - a bass reflex speaker will play louder than an acoustic suspension speaker when driven with the same amount of amplifier power. This can be a big benefit, especially if you're using a low-powered receiver or amp. However, what you gain in volume, you can lose in accuracy.