The Presonus Eris Sub 8 BT is a compact but powerful subwoofer that extends the frequency range of smaller loudspeakers such as the Presonus Eris 3.5 or Eris 4.5 BT downwards: It delivers an average power of 50 W and generates a maximum sound pressure of an impressive 103 dB RMS at 1 m distance. This makes it sufficient for basically all normal mixing sessions, but it also comes into question as a supplement for medium-sized home theater systems, stereo and compact systems, or the home DJ setup.
The Eris Sub 8 BT is equipped with an active crossover as well as connections for balanced and unbalanced signals, so it can be directly connected to active speakers and an audio interface respectively the consumer electronics of your choice. In doing so, you can adjust the input level and crossover frequency to your liking. An additional high-pass filter removes the sub-bass of the connected satellite speakers, which cleans up the sound considerably in problematic listening conditions, and a phase rotation switch allows a free positioning of the Sub 8 BT without fear of cancellations around the crossover frequency. The front bass reflex port also allows it to be placed directly against the wall.
Especially for small rooms, the Eris Sub 8 BT is a good amplification in the bass range and a useful supplement for small-diaphragm active speakers.