The Episode Signature Retrofit In-Wall Subwoofer Enclosure increases sound performance by adding consistent air volume. The retrofit enclosure is capable of housing a single subwoofer in the wall, or you can also add a second enclosure either vertically or horizontally for the perfect dual subwoofer configuration. Plus, the design allows you to install an architectural subwoofer after the sheetrock is added, while still getting defined air volume. This enclosure has a minimal footprint, so you can easily hide subwoofers anywhere – small or large rooms, theatres, distributed audio, and more. This enclosure is compatible with Episode Signature Passive Free Air Subwoofer. It must be purchased separately.