How do I tell if I have hard to work with Harmon Kardon amps or not and therefore whether changing the head unit will be easy or not.

Head unit is Alpine XQD101580LNF
Door tweeters day Harmon Kardon and backs of speakers do too.
Cant see anything in drivers door other than the Door Outstation.
There is a sub in the boot but it doesn’t work

Thanks

On the head unit, if you poke the button for changing the bass, treble, etc levels, do you have a DSP option? If you do, you've got the DSP system making fitting an aftermarket unit not as straightforward as if you have the door amps. Door amps would live lower down the door if they were there.

yes, it has DSP: None, DSP: Driver. I cant find any amp in the door though. Would it be tiny? I think i can trace the wires from all 3 speakers to the loom going through the flexi back to the car body too.

Yes, you have the DSP amp if you have the DSP option in the menu on the head unit and not the door amps. Door amps are roughly the size of a fag packet, only slightly smaller than the door outstation. DSP amp is tucked away behind the sound deadening behind the sub on the LH side of the boot. To fit an aftermarket head unit you have to bypass the DSP amp and add two pairs of speaker wires for the rear channels. With the DSP system, only left and right channels are sent to the amp with the fade between front and rear done in the DSP amp. All speakers are wired back to that and not to the head unit. Like the door amps it incorporates crossovers to split each channel between the bass speaker and the mid and high range speakers. You can jumper the left and right front channels from where they arrive at the DSP amp directly to the outputs that go to the speakers but to match the speaker impedances stop the sound quality going 'muddy' you need to put crossovers in those jumpers. That way, taking Left Front as an example, you'll have a pair of wires arriving at the DSP amp from the Front Left output of the head unit and two pairs of wires from the DSP amp to the Left Front door, one pair for Bass and another pair for middle and top.

i did this https://rangerovers.pub/topic/8-info-p38-alpine-dsp-amp-connections-and-wiring?page=1#pid30814 as a result of being asked about it on RR.net (but didn't publish it on there, why let them be the source of useful information after they removed all of what was there before?) and the guy managed to do it himself and got it all working.

thanks Richard, you're a great resource mate!

Pulled the door cards off my 1999 Thor and found the amps where Richard suggested they would be. So that's a bugger. It's 3 months older than my 2000 Thor and another thing is different! Already found the latches to be incompatible!! Hope the steering wheel is as want to swap that out!

That explains why the sub from the 1999 wouldn't fit the socket on the 2000 car...

If they both have the Alpine head unit, they will be the same. Steering wheel from a car with the Alpine doesn't work on an earlier car with the Clarion (or it does but the buttons all do different things to what you expect them to....).