Sounds like you have the high level inputs from your aftermarket deck plugged into the low level inputs of the factory amp.

 

i have the speaker wires off the head unit to the speaker wires as they come out of the back of the factory deck. from there they go to the factory amp, right?

 

the wire harness that i used is from a VW so yes the yellow becomes ignition and red becomes constant. i dont know if its the same harness you are using but that was the case with mine hope it helps and sorry about the keys it they work on mine. also how are you fitting a double din radio on the discovery?

 

i got it out with the metal inserts from a wiper blade...always finding new ways to use crap around the house!!
as for fitting the double din, i bought a used dash piece and cut it and molded it to fit the radio by getting rid of the lower cup holders and moving the heater control down. wasn't too bad, but took some time.

 

can you send a picture and if you were to make another one how much would you charge you?

 

i'm going to post some pics on here this weekend. i need to get out there during the day to get some decent shots!
and hmmmm, how much would i charge? i'd have to think about that. are you going to supply a donor dash piece for me to sacrafice? needs to be complete with the change tray, ashtray and cup holders.

 

The reason it's too loud is you are overpowering the factory amp. You are eventually going to burn it out, and then bad things are gonna happen. You need to find out if your aftermarket head unit has low level outputs, and then hook them to the factory speaker wires. The factory head unit does not have a built in amp, your aftermarket unit does.

 

i used the low level ones...the speaker wires off the back, as opposed to the rca's. and the wattage is so low on the head unit...18x4. i know it would make a little diffeence, but it shouldn't be this much.

 

my disco does not have the cup holders how does that work but yea ill get u a dash

 

The RCA's are your low level outputs. The speaker wires off the deck run through the deck's amp, the RCA's do not. You need to figure out a way to hook into the RCA's. I'm sure there's some sort of adapter out there to do this, you can't be the first person who's ever installed an aftermarket deck in a Disco.