Some observations setting the gain

My amp is a Audiobahn A8002T running with 2 12" Kicker CVRs 4ohm DVCs at 400wx1@4ohm. My HU is a Kenwood that is a few years old. According to the formula, I am supposed to set the gain to 40 volts. However this can only be achieved by turning the head unit up to 30/35. At my normal highest listening volume, the head unit is at 28 but the output cannot even reach 40v even all the way up with a max of about 36v. I am testing the output with a test cd with 50hz. Whats up with this?

Now for the Remote Bass Boost Controller. Once I have the output set to 40v with the HU at 30/35 I try and plug in this remote controller. The first thing is that it does not light up like it should as in the blue circle around the knob. Secondly, without the bass boost turned on, the max output i can get is 30v with the remote turned all the way up. Thirdly, if I turn the remote all the way down, the protection light + the power lights are lit up. Any reason for these.

Just so u know about the system completely, the subsonic filter on the amp is all the way up at 50hz, with the LPF turned to around 100hz in addition to an external crossover at 100hz with the gain turned to MAX on it. The whole system is securely grounded and wires are perfect so no need to worry about that.

Basically, I would like to know the following:

1) Why can I only get the output of the amp to be 40v when the HU is at 30/35? 75% of max volume as recomended is 27-28 which is the max i practically listen to it at.

2) Why wont my remote bass controller light up?

3) Does Bass Boost have to be turned on in order for the remote to work correctly?

4) Why does my amp go to protection when the remote is turned all the way down?

5) Why can I only get a max of 30v with the remote plugged in with a max of 40v with it unplugged?

Thanks alot guys for taking the time to read this long post. Any help/experience you guys have with this is greatly appreciated.

kk the amp is an 8002 but it would run 200x2@4ohm in stereo and i prefer to ha-ve it 400x1@4ohm in mono. I cant wire the speakers to 2 ohm. The light on the remote still does not come on when bass boost is on but im not gonna mess with it. How should it be 28v when the sqrt(400x4)=40? Any external crossover is better than a amp crossover which is why I use it, it cleans up the sound real nice.

Haem- How do I know what the box is tuned to? Its a sealed box i didnt know it was still tuned?

True Stevdart but what I have it set at now (30/35 40v) the amp is turned a bit more than 1/2 way up which is where I had it by just temporarily tuning it by listening to it. It sounds good right where its at with no distortion so I dont think the numbers are off that much.

Yes, it's exactly the same impedance on each channel.  A 4-ohm load bridged across two channels places half the load onto each channel.  Preferred way to wire DVC subwoofers:  coils in series, subs in parallel, bridged across the two channels or connected to a one-channel amp.

I like Haemphyst's advice here.  Very clear post.  However, I'd bet that many of you do not know what distortion sounds like.  I'm not talking about severe mechanical noise / unloading / or close to square wave clipping - I'm talking about distortion a little more subtle than that. 

Get the gain setting CD from Autosound 2000.  It has examples of various levels of distortion on real music tracks.  Learn how to identify the beginnings of distortion.  Use this same track when setting gains.  Apply Haemphyst's advice. 

Also, Stevdart's point re the problem with gains via a meter identified the issue - to be successful with that method the manufacturer needs to be honest.  Easier with Zapco; laughable with Audiobahn.