[bmwak]

Hi all,

Basically I'm looking at doing the Earthquake SWS-8XI (2ohm versions) sub upgrade and am a bit unsure on the wiring aspect of things, as most guides on here refer to cars with HiFi or Logic 7, but there is no definitive answer for basic non-amped systems (i.e. speakers powered directly by the Professional headunit).

I understand that once the Earthquake subs are fitted to the underseat enclosures that I will need to run wires back to the boot, where these wires need to directly connect up to the amp’s channel outputs (1x 2ohm amp channel per SWS-8XI Sub).

I will also need to wire the amp to the battery, a switched live and earthing point - all usual stuff and no problems there. But the point where i'm stuck is what wires in the BMW wiring do I tap into to pick up the sound signal from headunit. I believe I need to use a RCA hi/lo convertor and need to tap into a +ve and -Ve from both left and right channels to create a low level output which inputs into the amp.

Obviously once the stock subwoofers are removed the wire connectors for the subs will be redundant. So do I just tap into these from both sides and hook it up to the RCA hi/lo convertor? Logic says yes but I understand the front speaker signal is shared by the subwoofers and the mids on the bog standard system. With this in mind is it better to tap into the rear speaker outputs and wire the hi/lo connector to those?

Any help appreciated

[Fredz]

http://www.e90post.com/forums/showpo...66&postcount=1

http://www.e90post.com/forums/showth...#post2599482:D

[B33M3R]

Originally Posted by bmwak

Hi all,

Basically I'm looking at doing the Earthquake SWS-8XI (2ohm versions) sub upgrade and am a bit unsure on the wiring aspect of things, as most guides on here refer to cars with HiFi or Logic 7, but there is no definitive answer for basic non-amped systems (i.e. speakers powered directly by the Professional headunit).

I understand that once the Earthquake subs are fitted to the underseat enclosures that I will need to run wires back to the boot, where these wires need to directly connect up to the amp’s channel outputs (1x 2ohm amp channel per SWS-8XI Sub).

I will also need to wire the amp to the battery, a switched live and earthing point - all usual stuff and no problems there. But the point where i'm stuck is what wires in the BMW wiring do I tap into to pick up the sound signal from headunit. I believe I need to use a RCA hi/lo convertor and need to tap into a +ve and -Ve from both left and right channels to create a low level output which inputs into the amp.

Obviously once the stock subwoofers are removed the wire connectors for the subs will be redundant. So do I just tap into these from both sides and hook it up to the RCA hi/lo convertor? Logic says yes but I understand the front speaker signal is shared by the subwoofers and the mids on the bog standard system. With this in mind is it better to tap into the rear speaker outputs and wire the hi/lo connector to those?

Any help appreciated

Have a look at the link to my install in my signature, my car was esentially a 'base' system albeit with the professional idrive.

You're going to struggle powering anything off of the HU without an amp as it's pretty low on power. One of the main things to consider rectifying before amping and changing speakers with the base system is the cars in-built EQ.

The simplest way to tap into the cars wiring and keeping things easily reversable is to use a plug and play harness. Forum member 'Technic' will sell you one if you PM him, see my guide for info.

Don't tap into the rears as they are not fed by a full range signal. When you remove the under seats this connector need to be bridged, esle your fronts won't work.

Have a read of the guide, it should help give you an idea, if you have any questions ask away

Also have a look at the Alpine Upgrade offered by BMW, not my preference but lots of people have been very happy with the results.