Help with volume issue after tuning amplifier

[crash4444]

OK so I have the AVIC Z130BT and just added a JL Audio HD900/5 amp, per JL Audio instructions and many youtube videos, I was convinced that I need to tune the amplifier per the suggested settings in the owners manual. I unhooked the speaker wires from the amp, turned everything off on the HU, bass, boost, loudness, etc. and set everything to flat on the EQ. Hooked up the DMM to the speaker ports on the amp, put in sine wave tone in cd to play at 1khz, turned up HU volume to 30 our 40 or 3/4 and proceeded to adjust the gain on the amp. Suggested setting on 4 ohm load is 20.0V, well problem, I could never get the front channel higher than 16.4V, rear channel everything went perfectly and got it set to 19.9V, close enough for me. Set up the Sub channel with a 5Ohz tone, suggested setting on 2 ohm load at 31.6V, got it to like 31.4 so good enough. Hooked speakers back up to amplifier, turned on HU for what should be beautiful music and could hear nothing, then cranked the volume know and at about 35 it started sound OK. I only had to turn volume up to around 18 to 20 to be blasting me out of my car before then tuneup. After playing with the audio settings, I got it to sound pretty good but still had to crank the volume, but according to JL Audio, if I understand it correctly, I am not supposed to use the EQ on the HU after the tune.

 

So that being said, yes I am a NOOB but tried to research quite a bit before this.

 

1. what did I do wrong?

2. Why the low V on the front channels?

 

Suggestions on what else to do.

[crash4444]

Well eventually after redoing the process, I was able to get the numbers where they should be, why the difference in readings I don't know. But maybe just maybe it should have been a warning that something was up internally with my HU, as in a newer post you will read that the unit has died and been sent in under warranty for replacement. Just thought I would update this post as nobody replied with suggestions, and I didn't want people worrying that they may have issues with theirs. Just seems like I had a defective unit.