Alcorn McBride Knowledge Base

The AmptraXX is rated to drive speaker loads of 4 to 8 ohms. However, some speakers can actually have a much lower impedance at certain frequencies. The lower impedance often occurs at low frequencies, and if the impedance becomes too low the AmpTraXX output(s) will shut down. If your speaker has an impedance characteristic that goes much below 4 ohms (i.e. 3.5 ohms) at low frequencies, you should always program the AmpTraXX with a high-pass filter rolled off above whatever frequency your speakers maintain an impedance at or above 4 ohms. Most of the time, this frequency is in the 100 to 150 Hz range, but check your speaker specifications to be sure.