Resetting sound fields to the initial settings, Using only the front speakers and, Subwoofer (2ch stereo) – Sony HTSF2300 User Manual
Page 48: Resetting sound fields to the initial, Settings, Using only the front speakers and subwoofer, 2ch stereo), Press 2ch, Press ? / 1 to turn off the receiver, While holding down sound field +, press ? / 1
