JBL's most powerful studio subwoofer with very high continuous output and extreme low frequency response. JBL introduces its most powerful studio subwoofer for applications in which very high continuous output and extreme low frequency response is required. With in-room response below 18Hz and 137 dB peak output, the SUB18 delivers unprecedented performance for demanding dance music production, while providing exceptional accuracy required in cinema post production applications. As an add-on to JBL's M2 Master Reference Monitor system, the SUB18 allows three times greater output from the system.