Welcome to XFIREAUDIO welcome to Life Amplified! congratulations on purchasing one of the finest auto sound signal processors in existence. The X-Bass Pro is designed to deliver Bass, adding Bass is like breathing life into your auto sound system. No matter your choice of music X-Bass Pro will make you experience your music in an exciting new way. X-Bass Pro is not only letting you control the level of Bass added to your system, it also restore "lost Bass". Bass is filtered out of your system to protect your speakers of being damaged by low frequency energy. Not only is bass filtered out on some track in the recording studio but, many factory audio system are known for filtered out Bass as well. X-Bass Pro has got you covered here it has the technology to restore the filtered out low Bass. And to make it fully compatible to any source unit it excepts High and Low level input signal.