HPF and LPF settings

You should only need to use one crossover.  Try using the amp's, and keep the head unit at full range.  Set both high and low at the same point, about 80 Hz, so you don't have a hole in the frequency range.  Now as you have it, the sub attenuates starting at a low 50 Hz, and the mids bottom out at 100 Hz, leaving a gap between 50 and 100 Hz.

If I have my Subs set at 80hz I want my high pass to be set at 80hz also right?  Would I use my amps or my headunit's settings or both?

Headunit Kenwood DDX7015

1 Amp Us Acoustics 1000d

2 Amp Eclipse 5422

Okay will do... I have a eclipse amp and a us acoustics amp. My headunit is the Kenwood ddx7015

I'm asking another question please don't flame me!!!      Anyway, My Deck has a max volume of 35. I can run the volume all the way up, it seems this should be much louder and I shouldn't be able to turn it all the way up... I remember my old system with infintiy componets running off a clarion 50x4 amp with a Pioneer Premier deck that system was LOUD...

Yes, THR is Thru, or full-range, no filter.  Turn up the gain on the amp.  Decks put out different voltages to the preamp outputs.  Say I have a deck that puts out 5 volts of output when the volume is maxed out (forget the number, that is just the number of adjustment steps between no output and max output).  So, I turn up my volume to max and set my gains to just below audible distortion.  All set now.  But that deck gets fried, its broken.  Enter new deck!  The new deck puts out 2.5 volts, half of what the old deck puts out.  When I max out the volume on the new deck, it is only half as loud.   Awwww, new deck sucks   : ( .  Not really, the gain was set for the old deck is all, I need to turn the sensitivity up to make the amp reach full power with only the 2.5 volts of input.   So, if i have a low voltage deck, then i turn the sensitivity (gain) up, to make it very sensitive to a little input from the deck.  If i have a high output preamp of 5 volts of more, i turn it down to make it less sensitive.

YOU DO NOT ACHIEVE MORE POWER BY TURNING YOUR GAINS ALL THE WAY UP.  Your amp may even have marks on the gain/sensitivity adjust.  May say like .5v on one side and 5v on the other, some have marks in-between like 1v, 2.5v 3.5v.  They do that as a reference, so if you have a deck that puts out 2.5v you can easily set the amp, you may have to adjust to one side or the other but you should be close to that mark.  The idea is, if you set the gain at the 2.5 mark, and give it 2.5 volts of input, it will reach max output.  If you put it on .5 volts, apply .5v of input, it will reach max power.  Get it  : )  ?

I use both the deck crossover point and the amp for my subs.  For the full range I just use the one on the deck so I can control it.  I use both on the because i hate the hum  you get from speak and such, if I had a steeper crossover slope (say 24db per octave) I would be able to block this out with just one crossover set at say, 80hz or less.  It will not damage anything to do this, do it if you like.  I have a kenwood, forget the modle number, it puts out 2.4 volts max.  Hope this helps.

Well I readjusted my gain on my amp to 1volt when I turn it counterclockwise back towards the 8volt it's just not loud enough.(1volt mark is where the audio shop set it too orginally) Do I need the have the LP/HP at the sam frequency?  I sure I'm thankful for your help..

Nice explanation from heavilymedicate.  Lizardking, if you are setting gains at 1 volt input to get enough volume, then there may be a problem somewhere.  It seems to me that the deck should be outputting a higher voltage than that.

As far as crossovers go, the mono amp just has a low pass, so set it to where you want the sub to start attenuating.  This is usually 80 Hz, but some systems sound better at about 100 Hz, and some set a little lower than 80.  You'll eventually find your best sound with some tweaking down the line.  The other amp should have the high pass filter on at the same frequency as what you set the mono amp.