i turn the headunit to 39, turn it on the correct track, stick the red probe in the positive and clamp the other part on the amp ground wire, then play the track and it wont detect the hz, the signal light comes on tho, and then i turn the gain up and it will read distortion but the 40hz light never came on or 1hz when i did the full range amp
You need to turn your crossover(HZ) all the way up.