Part of a job lot that we've had sitting around for ages. Issues mainly related to ports and battery which are generally feasible to fix however the main issue has been getting these sealed properly again. With "Bass Up" activated these speakers produce immense amounts of sound pressure and if they are not sealed properly they will make strange noises as the sound exits from small gaps. We've recently produced our own replacement gaskets which for the most part seems to have solved these issues. This speaker has been tested with some extreme bass music to ensure it performs satisfactorily.