QSC Audio PL230A - Manual (Page 12)

HORN BOOST- These switches are only active when the amplifier is in BI-AMP
mode. These switches work in combination to control the amount of high-frequency horn
boost. The horn boost is adjustable from 0 to 14dB in 2dB steps as measured at 20 kHz.
Add the values of the selected switches for the total boost.
FEATURES & SETUP- SIDE PANEL SWITCHES: HORN BOOST
12