p2_1_left_engine_running_lowfreq + p2_1_right_engine_running_lowfreq
p2_1_left_engine_running_midfreq + p2_1_right_engine_running_midfreq
p2_1_left_engine_running_highfreq + p2_1_right_engine_running_highfreq

#You can find infromation about this feature in the User Guide https://simshaker.com/guides/sound/#couples
