Anyone know how to test the moon and tunes amp

[moonstonemike]

Audio Gurus, I need you help My volume level and bass have both dropped . I took it in to the dealer and they changed the head unit which did nothing, I brought it back today. The called in there electrical specialist technician . They call me back and say it sounds normal and has lots of bass. I tell them that there are 3 other vibes in my family and those with the stock system have more bass and are louder. It seems fine they say again. I ask if they tested the amp. They say no , but they used a test cd and said the levels were fine. So is there anyway I can test it . Maybe test the power going to the sub or something.