Wiring new sub using HK wiring

[Dino D]

Hi all,

I have just bought one of the sub enclosures originally made by 'dooby' from 'gizze'
The one I have was made with a JL 6w3v3 sub for 'shantybeater'.

I know that a new amp is required to run this to it's full potential. Until then can I just run it on the HK amp and use the existing wiring that's there for now?
(a proper ICE upgrade will be on the cards but much later).
My car has an Alpine CDE-9880R head unit and the standard speakers including the factory HK sub and amp.

The wiring for the HK has 4 wires - can these just be joined and hooked up to the new sub?

Pics of existing wires:

 

[GazHyde]

I can't quite get my bearings on that photo. Where is that connector located?

 

[Dino D]

Hi,
That connector come from the amp in the boot through bulkhead and is in the space where the HK sub was.
For some reason this speaker has 2 positive feeds and 2 negative feeds. Perhaps because of the gauge of wire used?

I have limited experience with wiring speakers but I recall subs having thicker wires than this.

 

[gizze]

If it has 2 positive and 2 negative the oem sub is a dual voice coil.
You need to work out of if you can bridge those 2 channels into one more powerful mono channel.

But for now just use one channel.

 

[Dino D]

Hi Gizze,
I've played about with it an got it working just using 1 channel.
I think I didn't connect it well as it stopped working after a drive so probably wire loose.
It sound pretty good even with the standard amp but clearly it has more to give with a better amp.

I will get around to doing this properly one of these days as well getting a different centre console bit (the one without the grille for the HK sub) as it doesn't sit flush with the box.
Will add a speaker grille too but must say I like the look of it open (so does my 2 yr old so best to cover it for longevity from little fingers!).

Right now with weather good I'm just enjoying driving and can tinker when it's cooler again!

 

[Dino D]

Got a little 100w amp and some wiring, just need some time to wire it all up.
Looking forward to it as this sub is impressing already with just one channel of power from the standard HK amp.
Will mount the second amp in the boot too so should be simple to wire up, just following the
HK wiring through to the boot.

Just thinking is there any benefit to using new wires (from amp to speaker) or should I just use one set of the existing HK wires (there are 2 of each positive and negative for the HK sub).

I'll have to look into how the remote signal works in the HK and draw a line from there to the new amp too. Will make separate new wiring and fuse to power the amp.

 

[David Cullen]

what is the output of the amp Vs the speaker? and ohms, is the sub 2Ohm? the single chanel probably gives you 4 ohms but bridging it will reduce to 2 ohm which is what it should be to run the sub, make sure the cables are sufficient ie they are not heating up or you could wind up with a disaster..... do some more research on matching outputs and ohms and bridging, its not as simple as just getting sound out of the speakers ;-)

 

[Dino D]

So finally for around to doing this.

The sub is 4ohm and so is the amp.
I've run new wires (RCA from sub output on the Alpine headunit, remote wire, wires from amp to sub and power wire with fuse for amp to battery and earth pints).
I've not bridged it as the sub is 4ohm.

I expected it all to play but no no sound from the sub at all. Amp is switching on.

My thinking is that there is something going on with the wiring from the headunit via the HK amp (I'm leaving that in place, just want to amplify signal to the sub for now).

The headunit already had 2 sets of RCA's running out if it plus all the other wires via the harness adapter.
Is it a case that headunit is still sending a sub signal via some of the additional BMW wiring and to make it activate the signal via the RCA I need to cut some of the BMW wiring from the harness.

 

[zedonist]

Have switched the sub output on on the HU? My Alpine HU, has options to switch the sub Preout on and off

 

[Dino D]

I think so - I adjusted the 'Sub Level' in the Sound menu and made no difference.
That setting worked fine via the old set up and I didn't have to switch anything on even after a battery disconnect, just change it from 0 to a higher number up to 15.

Will look up the manual for the Alpine and double check.
Thanks

 

[David Cullen]

do continuity check on the rsm cable

 

[t-tony]

Blimey Dave, you an insomniac or do you work nights?

 

[David Cullen]

no Tony, insomniac lol, I only need 4 or 5 hours and im grand

 

[t-tony]

Just wondered mate,I'm out of wad time wise 5hrs behind you guys for a while. Wish I could get by with only that much sleep, I always thought as you got older you needed less sleep. Not me I could sleep for England Dave.

 

[zedonist]

Dino, was the original sub working?

 

[zedonist]

Just another thing to raise, after market amps have the ability to take the signal from RCA via the Preout and a,so directly from the speaker channel, does the HK have this ability? My guess would be not, and on that basis may be being either under or over loaded, as you have run RCA to the HK, I would recommend just bi passing and using a standard mono amplifier for the best performance of your sub. This also generated another question as I was typing, HK Sub drives either one or two 5.25 speakers, I guess the rms of these is pretty low, and consequently the HK amp will not be that powerful, I would also assume that it would not be powerful enough to drive dooby dub, which means it could have burned its self out.

 

[Dino D]

@zedonist:
I'm running 2 amps - the new one just for the sub, the HK remains in situ for the rest. I've run the RCA direct from the HU to the new amp (+ new output wires from new amp to sub) so bypassed the HK totally (or I thought).
I'm thinking that there is a feed via the normal wiring on the harness for the sub via the HK amp. I have found some diagrams online from another forum user and will use that to track the wires down and take them out (that way the HU is sending the sub signal via the RCA only and not via the BMW wiring?). Does that make sense?

@ David - is RMS the remote wire? The amp is switching on and off fine with the HU.


And yes the sub works fine - it has been working via the HK amp and original wiring just fine for weeks (could only use 2 out of the 4 wires that the HK sub used of course).

 

[David Cullen]

sorry Dino, yes the remote wire, if the amp is getting power then you are fine.
very difficult to trouble shoot without seeing it :-/
is the original sub out of commission? does it have a power light on? the overload idea from Zed sounds like a viable theory

 

[Dino D]

Thanks for the replies guys.

The original HK sub is out of the car, in its place the new JL sub.
This sub did work fine for weeks on the standard Hk amp and wiring.
I have now put a new AMP and wiring so it NOT plugged in via the HK amp so not possible that the HK is overloaded.

The new amp is 100w RMS per channel. JL recommend 50-150w so it's in the middle.

Looking at the diagrams in this thread: http://forums.bimmerforums.com/forum/showthread.php?1805291-Audiopipe-subwoofer

I am thinking I need to lose the original sub wiring as with it in place it seems the headunit is sending the sub signal down those 4 wires rather than the RCA outputs hence no sound at all. (The original amp and wiring is all in place just no longer connected to the sub so still connected between the HU and HK amp.)

 

[zedonist]

Of I remember correctly the remote switch wire is blue for the amp, I am pretty sure there is also a blue wire with white stripe that is the auto Ariel lead, don't confuse these two