This d&b audiotechnik Ci-SUB 18 subwoofer is a powerful audio device. However, it has a known issue: the grille foam is missing. Despite this, it still offers great bass performance for your audio setup.

Using this subwoofer is easy. Just connect it to your audio system according to the standard connection method. When placing it, try to put it on a flat and stable surface to get the best sound quality. As for the missing grille foam, although it won't affect the basic use, you should be careful to avoid dust entering the subwoofer. For maintenance, keep it in a dry and clean environment. Regularly check the connection cables to make sure they are well - connected. If you notice any abnormal sounds, stop using it immediately and check for possible problems.