Alpine X-A70F Owners Manual - Page 11

SWITCH SETTINGS When performing Switch Settings, remove the Top Cover. For details, see "REMOVING THE TOP COVER" (page 3). • Before switching each Selector Switch, turn off the power and insert a small screwdriver, etc., perpendicularly to the Switch. Subsonic Filter (X-A90M/X-A90V only) The subsonic filter for cutting ultra low frequencies from the input signal before being amplified. This is desirable for several reasons: - To protect speakers too small or not capable of reproducing ultra low frequencies. - To minimize power wasted from reproducing inaudible sound. - To protect subwoofers in vented enclosures from over excursion below the tuning frequency. Crossover Frequency Adjustment Knob (LP FILTER) (X-A90M/X-A90V only) Use this control to adjust the crossover frequency between 50 to 400 Hz. Bass EQ Adjustment Knob (X-A90M/X-A90V only) Add a 50 Hz bass boost up to +12 dB to tune your bass response. 9-EN