I?ve done an upgrade on my E61 525d. The car was delivered with the Hifi system (676). In this system there are ten speakers. The HU is supplying the 4"midrange and 1" tweeter with 4 x 25 watt and there is a separate amp for the sub. This powered with 2 x 40 watt

My plan was to upgrade without cutting in the original wiring or any physical modification on the car.

My components:
- BSW Stage 1
- Earthquake SWS-8
- JL Audio HD900/5

Stage 1. Upgrading the SUB:

Here is some picture of the Earthquake SWS-8 sub. I soldier cable and connector for ?plug and play? to the original wiring.
Part number on the housing: 61136901731 (You need 2)
Part number on the pin: 61138364835 (You need 4)



Here you see the OEM sub. It?s very easy to replace these. Do not disconnect the cable to the seat. Then you would get an Airbag alarm







I created a 4 mm spacer in MDF.



The sub is installed:






Stage 2. Installing the BSW Stage 1 - 4"midrange and 1" tweeter.

Here is some picture of the BSW elements. This is 100% plug and play. Very easy installation

 

nice keep up with the install pics please.

 

Here you see the BSW speaker in the back. Less the 15 minutes to install both sides:





Original compared to the BSW:


BSW elements installed!




Stage 3 ? Upgrading the AMP

The last and probably most import upgrade. I?ve two adapters. One for the HU:



And one for connation to the OEM amp in the back





Here you see the new power cable. Very easy to install since the battery is placed in the back of the car. There is also a ground connector in the front of the OEM amp.



The JL Audio HD900/5 amp is temporaty connected.:




Result:

I?m very happy with this upgrade. I first upgraded the Earthquake sub and BSW stage 1. The sound became more clear and detailed but the Earhquake sub is not working vell with the OEM amp. After I installed the JL Audio amp the Earthquake sub start playing. The BSW element is also playing a lot louder.

 

I installed my SWS subs with a decent amp. I did not like it at all, it can play low notes but it wont hit high notes very well or sharp like the Logic 7 subs. I already knew they werent for midrange but just wondering what was your experience. BTW i put back my Logic 7 subs and amped them with the same amp and it sounds amazing with the trunk sub.

Edit: Just realized you have the HIFI system so you probably wouldnt know how the L7 subs sounded.

 

The SWS sub is not so god from about 100 Hz to 150 Hz, but the play loot louder than the Hifi sub. There is a cap between the Earthquake sub and the BSW midrange but after adding the amp this cap became smaller. I?m now trying to run the amp without the crossover and only using the crossover from the HU. I think that the sub is now playing from 0 ? 150 Hz and the midrange from 120hz. I first tried using the crossover on the amp, but it became better when I turned this off. I?m currently trying different setup and the next I?m going to thy is to crossover the sub at 120 Hz on the amp

 

Thanks for posting this!!! I'm looking to upgrade my Logic 7 as well. Couldn't believe that the "premium Logic 7 audio" sounds pretty much... mediocre.

 

Hi

Can you tell me where did you get the cables to connect the amplifier to the car? Did you made them?

Thanks

 

"I created a 4 mm spacer in MDF"

is there a need for the spacer? I'm putting in sws-8's next week and I thought it was drop and go!

I like that you put original plugs on but guess it wont make sense in my case as there's no amp in my current setup and consequently, the wires running to the current speakers under the seat come directly from the HU and wont have anything to do with the amp. Based on "Technic"'s advise, I will instead use these wires as inputs to the amp and consequently run 2 sets of wires between the trunk and the subwoofers.

 

very true, does anyone sell these kinda cables ready made, or do we have to go to our local DIY store and attempt a botched version lol

 

I made the cable myself. I order the "Autoleads SOT-903" adapter to get the connector. This is the only way I was able to get the connector. It's not possible to order this from BMW. The SOT-903 is for the Logic 7 amp, but the connector is the same for the Hifi. (For cars after 2008 the Hifi amp has a new connector)

I have one more of the adapter if you are interesting in buy one.