Frustrating Land Rover

Ok so this is my first post on this forum and I have used the search to try and find some answers but no success.  I'll start off by describing what I have done so far.  I have a 2003 Land Rover Discovery with the Harmon Kardon sound system with factory navigation in the headunit.  I need to keep the factory headunit for several reasons, nav, steering controls, re sale, ect..  So I set off to add a subwoofer and satellite radio. 

For the satellite radio I am using  product from soundgate that enables me to disconnect the factory CD changer and in its place install a Kenwood sat radio tuner.  As far as sub and amp, I am using a Kenwood 9152D mono 900 watt rms amp and a Diamond Audio TDX 12 woofer in a sealed enclosure in the rear. 

After wiring the amp for power and ground I proceeded to splice into the rear speaker wires (post factory amp) and connect them to the high-level inputs of the sub amp.  The results; terrible bass far from what I expected from this sub amp combo.  Even with the input sensitiviy at max the sub was just not delivering.  So my next idea was to istall a line output converter.  I connected it to the same rear speaker wires and used its RCA outputs to connect to the low level input of the amp.  The results; a little better but still far from what I expected.  The bass is quiet, terrible sound quality.  I set the output adjustments on the LOC to max and still could not hear much better sound.  Would it all work better if I ran the LOC off of the factory wires going to the factory subs, or would it be the same result?

So now I am at a stopping point with the sub so I figured I would turn my attention to the satellite radio.  The connections with the Soundgate unit are easy and straight forward.  When I switch my source on the headunit to the CD changer where the sat radio is now hooked up I get no sound (I haven't activated it yet but I should be able to hear the preview channel 184.)  So now I am completley frustrated. 

Anyone who has had any experience either with the same kind of problems I am having or has any knowledge/wiring diagrams for the Land Rover with the Harmon Kardon system I would really appriciate it.  I am getting close to scrapping the whole idea and keeping this stock.

As far as the terrible sound quality for the subwoofers is concerned, switching your source from the rear speaker leads to those for the factory sub should help quite a bit. Also, I have run into direct link tuners that put out no sound until they are activated, but check with Soundgate to make sure that your module is compatible with your factory nav unit. Hope this helps.

Your best bet is to use a LOC (Line Out Converter) to convert the speaker level inputs to RCA. Connecting the speaking level inputs directly to the high power input on the amp will not allow you to use the gain control. That is only for RCA level input. Using the LOC will allow you to gain match using the gain controls on your amp.

That is exacly right. The reason there is no output is because there is very little low frequency information to amplify. Tagging the loc to the speaker level signal going to the sub better. Tagging the line level input at the factory amp, and adding a line driver would be a better option.

Thanks for the help guys.  I bet you are right about the speakers I'm tapped into, they probably have the low frequencies filtered at the factory amp.

Now you are saying I could tap into the line level for the factory subs before the factory amp?  For that I would need a wiring diagram for sure.  And does a line driver just convert that to RCA's I could then feed the sub amp with?

Thanks for all you help.

i know you can catch the sub outputs from the factory amp for your LOC and your aftermarket sub will work fine.  What sucks is that every speaker in that truck has its own set of wires from the amp and they are all crossed over to match that speaker.  I dont remember the wire colors but i think there was a  gray/green and a gray/red for the drivers door 6.5 thats low passed. the wires for the front door 6.5s were thicker gauge than all the other speaker wires at the amp, including the factory sub wires.          One other thing,  Im pretty sure that the factory head unit doesent change the voltage on the audio outputs to raise and lower the volume.  The head units audio output is either on or off and when you turn up the volume, its data that tells the amp to either increase or decrease its output.  Ive seen this in the new Durangos and other Chrysler vehichles with the infinity audio.  Does anyone know if there is an adapter for the Rover like there is for the Chrysler stuff?

Well I finally tapped into the factory subwoofer wires.  All I can say is wow, a world of difference.  The sub now sounds the way I thought it should.  As for the satellite radio on the other hand, I have activated the sirius reciever and still no sound at all.  I called Soundgate and they said activating it should work but I guess not.  Back to the drawing board on the satellite.  Maybe get the Soundgate adapter that simply makes an aux input and buy a standalone sat tuner?  Let me know what you guys think.