[bruce_miranda]

I have the UK Hi-Fi sound system which means I have two subwoofers under the seat driven by a small amp in the boot. This is the standard US sound system so should be something a lot of people can do.

I finally decided to change the sub woofers under the seats to give me some more low end bass. I'm quite happy with the volume its just that the factory amp and subwoofers cross over too high.

I bought a pair of Earthquake subs and will show you how I install that. I also bought a second hand 4 channel amp to drive these subs because they each are capable of handling 150W RMS, so you need an amp that is atleast as powerful if not slightly more.

The guide is probably going to be completed in 3 parts because that is how I intend completely this mod.

Today I will cover creating a plug for the amp to plug the new amp into the car's wiring. I don't think anyone will have ever thought how much time went into this part but hopefully i will give you a headstart. I was looking for an OEM solution to connect the new amp into the current wiring system.

The current amp in the back is connected via a 20 pin plug - BMW part no 61 13 1 383 502. This plug goes into the amp and the connector is BMW part no 61 13 1 383 515.9. The biggest problem is that neither BMW nor Tyco/Amp will sell you the latter part. That's when I came up with the following solution.

Buy a plug BMW part no 61 13 1 383 502 and then buy some Tyco 2.5mm pins (RS Stock no. 395-7381). The Tyco pins are actually the same OEM pins used inside the plug I need but I'm buying them separately. They come as a set of 10 but I needed 11! so needed to buy two sets.

The car wiring to the amp in the 20 pins plug is as follows

4.0 RT/GN pin 10 +ve [12V+ line]
4.0 BR pin 20 -ve [12V- line or earth]
0.35 WS/VI pin 9 RAD_ON [Remote on]

0.75 SW/VI pin 13 AZBL- [Line level Left input -ve]
0.75 SW/RT pin 3 AZBL+ [Line level Left input +ve]
0.75 SW/BR pin 4 AZBR- [Line level Right input -ve]
0.75 SW/WS pin 14 AZBR+ [Line level Right input +ve]

2.5 RT/WS pin 8 ZBL+ [Speaker output Left +ve]
2.5 BR/GE pin 18 ZBL- [Speaker output Left -ve]
2.5 RT/BL pin 6 ZBR+ [Speaker output Right +ve]
2.5 BR/WS pin 16 ZBR- [Speaker output Right -ve]

Pay attention to the set of first numbers which show the thickness of the wires. Now you can use any wires that are atleast as thick but I decided to use OEM BMW wires because I find the copper used inside the OEM wires is top class. Most important is the match the thickness grade of the wires. No point using thicker wires because 'a chain is as good as the weakness link'.

Next you need to modify the plug you just bought and knock off the outer locking mechanism but releasing the two catches at the side marked in the picture.
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You should be left with a part looking like the image below.
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Then crimp your wires to the tyco pins. I always like to solder my wires to pins but you don't need to do that. Do not test inserting the pins into the plug housing because you will not be able to remove without destroying the pins. The design of these pins and housing is absolutely brilliant.
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Now when you put the plug housing to the car's harness plug you'll realise that it doesn't line up. The reason is its the same gender and so it won't however you will notice that the last few holes on one side do not have any connections. We will use this fact to our advantage and line up the holes so that we can connect all the wires together between the two plugs.

Done correctly and your plug should look like this and it will fit absolutely snug.
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Instead of buying phono / RCA splitters etc I decided to make a cleaner install. You need this only if you are using an amp in bridged mode. I bought a stereo phono to phono cable, cut it in half and soldered the wires of both plugs into the Tyco pins. Same result with much fewer parts and looks clean too. Used some shrink wrap to keep the ends of the coax cables neat.
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Some nice matt cloth tape around the lot and it looks like the rest of the car's harness and is ready for the amplifier to be installed. Even the lock part that I removed wasn't wasted, I used it to cover the power connectors on the amp.
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I'll add to this in the next few days showing the amp install and the subwoofer install. But so far not a wire has been cut and no irreversible mods too - main aim for all my DIY projects. All parts used so far are OEM, except the amp and subwoofers (but isn't that the whole point).

Lesson 2 : Amp placement and install. See below. http://forums.e60.net/index.php?showtopic=...st&p=501783
Lesson 3 : Speaker install. See below. http://forums.e60.net/index.php?showtopic=...st&p=502543 and http://forums.e60.net/index.php?showtopic=...st&p=504207
Lesson 4 : Tuning the system. See below. http://forums.e60.net/index.php?showtopic=...st&p=504389

[thedreamshop]

I want to give you props for what you did. I like the idea of a plug n play job quite a bit. I included a picture of the HI-Fi subwoofer amp that you are replacing so the other guys to see. The factory amp for those two subs is underpowered and if you look at the size of it then it just makes sense.

Attached File(s)

•  Hi_Fi_amp.jpg (36.24K)
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[Anthony517]

I'm getting sick of the stock amp also. I listen to all kinds of music and I hate no having any bass, so I decided to get a small box. 2 10" Orion subs with a built in amp. I got a price of $300 installed form a local place.

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[Shamu]

Thank YOU, Bruce, for posting this (and future) info! Much, much appreciated!!

Question: does the sub/amp replacement or perhaps addition of a sub/amp differ greatly for cars with Logic7?

[DRANGED]

Bruce, you never cease to amaze me with your rewiring mods. You are the king of schematics. Awesome job.

[bruce_miranda]

Shamu, on Nov 29 2007, 06:47 AM, said:

Question: does the sub/amp replacement or perhaps addition of a sub/amp differ greatly for cars with Logic7?

Yes it will differ quite a bit.
Remember the Logic 7 amp does all the processing and outputs Speaker level outputs. But you can use this similar method to tap into the speaker level outputs and connect them to your amp. In the Logic 7 amp you will need a bit more wiring (3 way) from the car's harness to the stock amp and then out into your amp back to the car's harness.

[Black BMW530iA]

thedreamshop, on Nov 29 2007, 03:52 AM, said:

I want to give you props for what you did. I like the idea of a plug n play job quite a bit. I included a picture of the HI-Fi subwoofer amp that you are replacing so the other guys to see. The factory amp for those two subs is underpowered and if you look at the size of it then it just makes sense.

Could i please get this picture in a bigger resolution?

[bruce_miranda]

Black BMW530iA, on Nov 30 2007, 12:49 PM, said:

Could i please get this picture in a bigger resolution?

See

http://forums.e60.net/uploads/monthly_07_2...-1185145213.jpg

The amp being replaced is the silver box on the right hand side that is not marked with the arrow. You'll see the big 20 pin plug with the coloured wires that I am planning to plug into.

[spindrome]

nice job Bruce. Looks very stock.

I just completed the SWS-8 upgrade myself and I'm quiet impressed how the puny enclosures under the seat allow the woofers to move enough air to give me some decent bass. I'm powering them with a 250w TMA amp. I've got them crossed over at about 125hz.

I have enough bass to satisfy my musical taste and I don't have to give up trunk space. (sorry ya'll, didn't mean to rhyme that).

[bruce_miranda]

Where did you install the 250W TMA amp so that you didn't loose boot space? Also isn't a 250W a bit unpowered for the speakers, I too am not intending to blow the place up with Bass but I like to know that the amp is able to drive the speakers connected to it completely.

[spindrome]

i've got it mounted inverted on the rear package tray, just below the left rear speakers. (per another post) - i'm not worried about it overheating as the heat sinks are off to the side and there's plenty space around the amp, and heatsinks are on the side of the amp.

It's a mono sub amp, and with the subs wired in parallel, i'm drving the amp at a 2ohm load. the power is more than enough and the amp doesn't even get hot. i get decent enough spl for my wife to tell me to turn it down and for the door panels to rattle when playing rap/hip-hop.

People that sit in the car will listen and ask "where's the sub box?" They'll be surprised when I show them an empty trunk.

I'd definitely recommend at least 200W though to drive these subs. They aren't the most efficient (86db 1 w/1m) probably due to their slim design, but they are the only option to drop into the factory sub enclosures under the E60 seats.

I bet the stock subs would sound decent as well if you just replaced the factory amp with an aftermarket one.

bruce_miranda, on Dec 1 2007, 03:53 AM, said:

Where did you install the 250W TMA amp so that you didn't loose boot space? Also isn't a 250W a bit unpowered for the speakers, I too am not intending to blow the place up with Bass but I like to know that the amp is able to drive the speakers connected to it completely.

[bruce_miranda]

Lesson 2 : Amplifier placement and install.

This was probably the most time consuming task in terms of getting the right sized amp that could fit somewhere discreet. And where more discreetly could I put this besides where the current amp is. However any amp that is capable of driving a 150W RMW subwoofer is almost never going to fit where the stock amp is. But I came up with a solution.

I don't have any extra units over my left wheel arc so there was a lot of place there. Besides that is the best place for anything that needs to stay cool because there are air flaps just over the wheels.
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After many months of looking at eBay I finally found an amp that was both the right size and power.
I built a platform for the amp out of some mdf, made some brackets out of aluminium and it was a perfect fit. You will notice that there are screw sockets already in there and I made use of them itself without drilling a single hole into the chassis. The black hex nuts that I used are BMW OEM Parts No 07119902932.
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I needed to use right angled phono sockets so that the entire thing would fit in.
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I had also realised that my standard left wheel boot trim would not work but Radioham let me have trim that is used for the cars with the DVD changer etc BMW part no 51477122193 and oddment tray 51477074479. This is not a picture from my car but you see the part I'm talking about here (forgot to take a picture of this part before it got dark today).
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Once done there is no signs of an aftermarket amp. I've yet to tune the system because I've yet to install my sub-woofers. That will become Lesson 3.

[spindrome]

nice job again, Bruce!

Is there enough ventilation with the new quarter panel? Will you need to create some hole(s) for the amp's heat to dissipate
Did you get your power from the grommet as well? The power cable seems thick enough gauge and the stock amp already has a 30amp fuse in the boot fuse compartment above the battery.

Have you tried hooking up the amp to the stock subs? If so, I'll be you'll be impressed with just the increase in power.

Let me know if you had any mounting problems on the right side sub enclosure. Mine did not sit flush with the enclosure so I had to get a dremel tool and cut out a lot of the plastic injected molding around the sides and bottom.

[bruce_miranda]

I don't intend to make any holes or anything. There is plenty of room in the space for the heat to escape plus as mentioned the air flaps are just above the amp itself. If I do feel that the heat is getting excessive I always have the option of simply not installing the oddment tray, then the amp can use the entire boot to dissipate.
All connections including power are taken from the car's wiring harness itself that was going to the OEM amp. See my first post you'll see that all the amp's wires terminate at the DIY plug itself. The wire gauge is 4mm and that should be good enough for my intended volume level. Ofcourse if I was the thumping type then that wire may be a tad too thin for the power. But as mentioned I'm truely impressed by the quality of the BMW OEM wires and thats the reason I spent money and bought them as spares. The BMW dealer must have never sold BMW wire to anyone before :-)

[spindrome]

keep up the good work bruce. let us know how it looks/sounds when all is said and done.