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1995-2002 Range Rover P38A
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Discussion Starter #1
I have a 2001 P38 Vogue and the subwoofer surrounds were shot. Managed to get some replacement foams and did the repair but the results weren't too great, one sub came out alright but the other had a lot of distortion, sounded like something was cracked and reverberating. I tested the subs against my hifi amp and got the same effect, tested my hifi sub on the car's subwoofer amp and got decent bass out of it. So I thought I'd check for replacement subs.

Getting stuff locally is difficult and I had to tell many of the sound guys here that "yes, you do get 6" subwoofers". Managed to source some from South Africa, "Hertz EV 165.5" (there's also a "Hertz EV 165L.5" which is better suited to lower frequencies but I couldn't get them"). The Hertz speakers fit perfectly and the holes even line up with the original holes, you just need to make a plan because the lip on the subwoofer interferes with the head on the original screws.

I've plugged in the new subwoofers and I'm not getting that distortion anymore but I'm getting a fair bit of noise. This noise is always there, I set the subwoofer down to -9 and had the radio volume at 0 and I can still hear it. I wiggled the wires around and plugs but no improvement, next thing to check is the earth connection. Is there anyone with similar experience? I've read up on the subwoofer threads a couple times and I haven't seen anyone discussing noise, only either the amp is dead or the subwoofer is shot, but I didn't find any discussing funny symptoms. The subwoofer amp I have is the one pictured and the system is the Harman Kardon one.

HK Subwoofer Amp.jpg
 

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1995-2002 Range Rover P38A
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343 Posts
Wait for marty_nz to chime in or send him a pm. He knows his way around when it comes to the HK puzzles.
 

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1995-2002 Range Rover P38A
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29 Posts
Discussion Starter #3
Update: Didn't have time to do any fault-finding last night but I checked my other speakers and it turns out that noise is present at all speakers when radio is set to zero volume. Oh, and mid-range speaker on right rear door seems to be dead.
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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4,219 Posts
Is the head unit original? or is it aftermarket?

If it's aftermarket, then noise in the system is unfortunately common due to the fact that the vehicle amps use a balanced audio signal, and most aftermarket head units with a line out on them use an unbalanced signal.

If it is the original head unit, then it could be a ground problem. You mention it is a 2001 vehicle... does it have the factory navigation in it? Or do you know if it has a DSP amplifier (it's fitted behind the trim that is behind the subwoofer)

If it has a DSP amp, then it could be that starting show it's signs of age - as they seem to have a bad habit of randomly failing. If it has individual door amps, then not sure... I only wonder about the DSP system, as that sub amp is from the later systems with the 'premium' (DSP) sounds system - I had one of those sub amps in my P38 but one of the channels is dead on it - and I haven't gotten around to trying to fix it yet!
 

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1995-2002 Range Rover P38A
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29 Posts
Discussion Starter #5
Reviving this thread because the DSP amp has now started a new trick.. Have an audio recording (which I don't know how to attach here). Best I can describe it as is a "squelch" noise whenever I switch off the radio. Car has original head unit and no factory navigation. I've checked the earth cable next to the left rear seat belt and that was in good condition (still cleaned it for what it's worth) and no change. Checked the amp plug and that all looks clean, no rust.
IMG-20180908-WA0019.jpg

IMG-20180908-WA0020.jpg

Any ideas what the noise could be? Is it a typical failing DSP amp sign? I can email the recording if someone wants.
 

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1995-2002 Range Rover P38A
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29 Posts
Discussion Starter #6
Don't know how to edit previous post.. Cleaned amp plug with contact cleaner just for kicks, thought it solved the problem because the squelch was gone.. turned out the squelch was gone because the sub was unplugged. As soon as I plugged the sub back in the squelch was back. Maybe the problem is the subwoofer's amp?
 
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