[mike_b]

Hey guys, I been reading through the threads in this section for a while now and noticed all the questions about 12v remote out for an aftermarket amp. I had an E46 318ti with the business HU - there was a white wire going into the HU that was to supply power to the HU light. I tapped this as a remote for my amp and it worked perfectly. When the HU came on the amp came on - didn't even need the ignition turned on.

Has anyone tapped into the harness of the E90 professional HU for a remote? I saw a wiring diagram somewhere and it looked like there was the same white wire for the HU light?

You guys have inspired me to upgrade the sound in my recently acquired E90 323i M-sport. I'm installing a DLS K4 split system in the front and 2 X 10" RF P1 subs in the trunk. The splits to be powered off the HU and subs off a RF301M amp. I'll leave the OEM rears and woofers under the front seats as is for now...

[cassey]

Learn how to use the "Search" feature. Read the recent thread titled "Low Voltage Trigger".

[mike_b]

learn to read buddy.

My question is specifically about tapping into the little white wire on the HU harness. Nobody has mentioned that as an option or a possibility yet.

[sageashton]

There is a trigger wire, but the wire is not white (that I know of). In the OEM amp harness there is a small, BLACK wire, this is the low voltage trigger and is what you use. It's pretty easy to spot as it is one of the only wires that is not twisted in a pair.

[fdiprete]

Many people here have used the black wire in the amp harness.
I will be using it also.

Here is a link to the thread I started to pull together the links for audio upgrade. In the pic I took you can clearly see the black wire in the bundle.

http://www.e90post.com/forums/showthread.php?t=164359

[mike_b]

Hey thanks for the replies.

fdiprete, I actually read your post - nice one. The thing is, Here in South Africa, the professional sound system does not have an oem amp. It's basically the HU front channels powering the 6" woofers under the front seats and the 4" mids in the front doors and then the rear channels on the head unit powering the mids on the rear shelf.

So I don't have a harness for the amp like in your pics...
That's why I'm trying to find a remote from the head unit's harness..
Maybe I should just use a trigger - but I've heard that if there is silence, like between tracks, the amp switches off?

[Technic]

Originally Posted by mike_b

Hey guys, I been reading through the threads in this section for a while now and noticed all the questions about 12v remote out for an aftermarket amp. I had an E46 318ti with the business HU - there was a white wire going into the HU that was to supply power to the HU light. I tapped this as a remote for my amp and it worked perfectly. When the HU came on the amp came on - didn't even need the ignition turned on.

Has anyone tapped into the harness of the E90 professional HU for a remote? I saw a wiring diagram somewhere and it looked like there was the same white wire for the HU light?

You guys have inspired me to upgrade the sound in my recently acquired E90 323i M-sport. I'm installing a DLS K4 split system in the front and 2 X 10" RF P1 subs in the trunk. The splits to be powered off the HU and subs off a RF301M amp. I'll leave the OEM rears and woofers under the front seats as is for now...

I don't think that your main issue right now is getting a remote signal, but getting a better set up than what you posted here.

IMO, that DLS K4 will be a waste if powered by the OEM HU, as it only puts out some 15W max at 4 ohms, and that impedance include the underseat 6.5" mid bass drivers connected to the front OEM 4" driver and an inline cap as a high pass filter to the 4" driver.

Because these two front OEM drivers are connected in parallel that means that they are 8 ohms each (4 ohms parallel). Your plan then means that one 8 ohms driver will be replaced by a 4 ohms, which will make the total impedance 2.7 ohms. I don't think that your Professional HU is stable at that impedance.

Even if you can pull off that front trick (I doubt), your 10" subs will completely overwhelm those front speakers with that low power.

[JoeyFiasco]

Originally Posted by mike_b

learn to read buddy.

[fdiprete]

If your setup is a head unit only, perhaps the blaupunkt solution is the way to go. I would.

http://www.e90post.com/forums/showth...ight=blaupunkt

Or if you are trying to just find the remote wire perhaps a little research into the pinout of blaupunkt's oem connector may help.

Cruthfield sells them

http://www.crutchfield.com/App/Produ...PNP017&tp=6348

Try searching around for a pin out for that head unit connector. I don't have a link for you because I have a different problem that I am researching.

[mike_b]

@Technic, the DLS K4 split is designed to perform best off OEM head units. The sensitivity is 91db. I'm not too worried about the bass integration from the subs in the trunk. I have been into car audio for over 10 years and have had some really nice systems. Things have changed though and I have a toddler and one in the oven, so budget is really tight. I like the challenge of building a system with entry level equipment and making it sound better than it should

I had a simmilar set up in my previous car, the E46 318ti. I was running my RF subs and amp in the trunk and Hertz DSK 6.5" splits off a Kenwood HU. With a bit of tuning and correct setting of the crossover points on the HU, I had it sounding real sweet.

I am a bit worried about the impedance load on the HU though... I must just double check that the 4" driver is 8 ohm like you say. It makes sense that it would be. I might have to disconnect the 6" woofers under the seat. What would happen if the HU cannot handle 2.7 ohms?

[Technic]

The issue in your proposed system is the combination of low power and impedance stability, not just one single thing.

The DLS K4 alone would sound "acceptable" with just 7.5W RMS @ 4 ohms by themselves at that sensitivity but not with the underseat subs and a filter cap still connected to them. Your Professional HU would power all those speakers so-so for some time at low volume, until the excess heat eats up the OEM HU amp IC by running constantly over 7.5W RMS because of the reduced impedance.

The OEM schematic shows the underseat woofers connected in parallel to the front speakers, so for this front set up to be in the safe side it would be a good idea to disconnect the underseat subs and the filter cap as you said, and let the OEM HU drive the K4 on its own. You can make up any mid bass loss by raising the trunk subs low pass filter to around 150-200Hz.

Originally Posted by mike_b

@Technic, the DLS K4 split is designed to perform best off OEM head units. The sensitivity is 91db. I'm not too worried about the bass integration from the subs in the trunk. I have been into car audio for over 10 years and have had some really nice systems. Things have changed though and I have a toddler and one in the oven, so budget is really tight. I like the challenge of building a system with entry level equipment and making it sound better than it should

I had a simmilar set up in my previous car, the E46 318ti. I was running my RF subs and amp in the trunk and Hertz DSK 6.5" splits off a Kenwood HU. With a bit of tuning and correct setting of the crossover points on the HU, I had it sounding real sweet.

I am a bit worried about the impedance load on the HU though... I must just double check that the 4" driver is 8 ohm like you say. It makes sense that it would be. I might have to disconnect the 6" woofers under the seat. What would happen if the HU cannot handle 2.7 ohms?

[mike_b]

thanks for the advice Technic. Would the filter cap on the front speakers be in the doors next to the speaker? My ideal would be to power the K4 split off the front channels and the under-seat woofers off the rear channels and leave the rear speakers disconnected.

[Technic]

Originally Posted by mike_b

thanks for the advice Technic. Would the filter cap on the front speakers be in the doors next to the speaker? My ideal would be to power the K4 split off the front channels and the under-seat woofers off the rear channels and leave the rear speakers disconnected.

I don't know where the cap is just because we do not have that sound system option in the USA.

The issue with the cap is that it would raise the frequency to the K4 to a range that it could defeat their purpose (coaxial). As the underseat woofers are going to be eliminated you will need the K4 to take over some of the frequencies of those woofers. That cap will not allow that.

You need to find out what is the actual impedance of the underseat subs before connecting them to the rear OEM HU channels. If they are in fact 8 ohms then the power will effectively be reduced by half.

That's going to be some low power woofer...

[mike_b]

bro you are right again - I must be rushing the thought process, you catching me out at every step

The DLS K4 is a splity set/component set. I visited a scrapyard in Johannesburg city (scary place!) on Saturday and bought me some door frame pieces that run from behind the side mirror and follow the top frame of the door. I am mounting the tweeters in fibreglass pods on the spare pieces and keeping the original ones stashed away safe and unspoiled.

One of the DLS specialist dealers that I know from a local forum delivered the speakers to me at work today. I spoke to him about the impedance issue on the HU running the K4 and the underseat woofers. He said that they had done simmilar installs in E90's without any issues. I might just try my luck and run it like this - hopefully the HU will go into protect mode befor it overheats and does some damage...what do you guys think?

I have also decided to buy a trigger device that uses speaker level input and gives a remote out aswell as rca outs.....seems like you guys were right all along. It's not easy to find a 12v remote in the oem wiring and not worth doing anything risky.

I'll post pics when I get somewhere with the install.

Thanks for the input.

[cassey]

Originally Posted by mike_b

learn to read buddy.

My question is specifically about tapping into the little white wire on the HU harness. Nobody has mentioned that as an option or a possibility yet.

Do your research before you try to bash anyone trying to help you.

[mike_b]

dude, I wasn't trying to bash you so calm down. I was giving you like you gave me...

Anyways, I was trying to tell you that I did a search - I read the posts - I did not find any answers to my specific query- So I asked a question. That's what the forum is here for.

No hard feelings man.