This D&B Audiotechnik Ci-SUB 18 subwoofer is a great audio device. However, it has a known issue: the grille foam is missing. Despite this, it still offers powerful bass performance and is a reliable choice for audio enthusiasts.

Using this D&B Audiotechnik subwoofer is easy. Just connect it to your audio system properly, and you'll enjoy rich bass. Note that since the grille foam is missing, be careful not to let dust or small objects get inside the subwoofer. To keep it in good shape, clean it regularly with a soft, dry cloth. Also, place it on a stable surface to avoid any vibrations that could affect the sound quality.