3.0si Roadster Coupe - Sound system upgrade

[peste]

I've been lurking around here from august last year when i bought the Z4. Like i did in many other forums i restrained from posting until i had something relevant to post, so here it goes:

First the car:
It's a 2007 (first registration in feb 2008) 3.0si Roadster with M Sport suspension, M Sport seats, Xenons, 6Speed Auto and Sports Mode, auto dimming mirrors and rain and light sensors. (i have no clue if this was a standard or not).
The car was bought from a BMW dealer with 37000km on the clock (about 24k miles) for and i got a hardtop as a bonus.

Here she is when i picked her up from the dealer:





Then her first (long) drive:



Then winter came and i switched to winter tyres:




and finally this spring she got her first detailing - in and out



I'll end this post here and continue in the next one - asker to follow this way.

 

[-Tom-]

Welcome along. Great intro and love the colour combo!

Sent from my Nexus 5 using Tapatalk

 

[NeilP]

+1 on what -Tom- said!

Great colour combo. Welcome

 

[peste]

Anyway, all in all, as one may guess i have a soft spot for this car and so i decided her mediocre (at best) sound system needs an upgrade. I used to be an EMMA International headjudge and used to compete in EMMA Advanced 7 back in the day. Since i still a ton of Car audio stuff left over and not a lot of places to stick them in.

Basically the concept is simple keep the stock HU but modify it so that i can get 4xPreOuts, one amp, 2way components up front and an active subwoofer behind the drivers seat (i'm a short guy so i don't need the seat all the way back).

After listening to all these useless small subwoofers i decided that the best one is still garbage but better than the rest (at least it can reproduce SOME sub-bass. So i chose the iNphase USW12 http://www.caraudiocentre.co.uk/product_m-in-phase-usw12_p-31934.htm - first link that came to google. Basically a quite nicely built aluminium enclosure with two 6.5 inch drivers driven by a (not so) powerful 150w mono block amp.
I chose a small alpine amp that i got online as broken (Alpine PDX F4), the tweeters and crossovers from a pair of old ALPINE SPX-F13M and as a mid bass speaker i can chose from the following :
JL Audio C5
Brax Matrix 6.1PP
Ground Zero Nuclear
Ground Zero Plutonium
and a couple of lesser stuff.

the plan is to have the system look as stock as possible, keep all functionality and first of all not to mess up the nice lines of the interior.

So first thing's first:
Fabricating the tweeter mounts :

i start by lining stuff up :



then on to the fabrication




then after quite a few layers of putty and 1k filler (no pictures here - sorry much to dusty for my iPhone) -on to paint



and finally , after polishing the tweeters so they match the brushed alu trim:




meantime in the car:



next modifying the amp

 

[peste]

ok, so for the amp:

i bought the amp in a sorry state without it's special connector which i thought i could buy for cheap. Boy was wrong, they cost all in all about 100 pounds. i paid for the amp 30 so.... no way, but .. no problem.
I bypassed the connectors, added some connectors i used to use in university for signal acquisition (so they don't induce any unwanted noise - at least not in the 5hz to 50 kHz spectrum )and soldered directly to the board two 12awg leads to both positive and negative terminals and added another fuse holder within the 4 inches from the amp.
Because the amp won't fit under the carpet in the original location i will also move the RCA connectors on cables so that i can reroute this also.
basically you can see it fits in the stock amp hole here:




This is far as i got and i am only working on this on the very limited free time i have - but i do hope to have it done in one maybe two weeks.
I will update as fast as i can

 

[NeilP]

Love the fab work on the tweeter pods!

 

[peste]

Pods attached to car - oem tweeters still active until evening (or until the rain stops). Please don't mind the dirty finger prints.

Driver's Side



Passenger's Side



I pointed them downwards simply because with the windows down and above 40kph the winds cut them out if they are pointed straight at me - it seems the BMW engineers took the same approach for the same reason - This will result in a low stage but it's better than no high frequencies....

 

[jimbo1958]

Nice work Peste.

 

[peste]

So, now that the tweeters are finally up and running (i simply soldered the old capacitor in line for the time being so that i could run them with the stock HU amplification for the moment), i had to get preouts from my headunit. This is actually not complicated at all provided you have at least a very limited knowledge of electronics and some decent soldering skills.
Since there is no schematics for the BMW Business HeadUnit i opened the HU up :



and identified the amplifier section



which is powered by a TDA7560 amplifier



I then looked up the pinouts for the IC



and proceeded to marking my soldering points for the pre-outs:



After this it's simply a matter of soldering some female RCA plugs and some wires. I chose some coaxial wire that i had around the house and some decent RCA plugs (cost per plug around 2Eur - nothing to fancy). Because there was no point in soldering directly to the IC pins if beeped some soldering points that were coming from the IC legs and soldered there:



I then tied the cables together and made a slot in the backplate for the cables to fit snugly through and that was that



I now have a BMW Professional CD Player with RCA pre-outs. It works perfectly and actually sounds a lot better then expected (the CD transport unit is actually a very good quality one)




I have also laid speaker wires in the car and RCA cables from the front to the subwoofer and amp location.
Next step: amp installation and crossover fitment.

 

[peste]

so now for the subwoofer just a few pics and words:

It is mounted behind the driver's seat and for now i'm using high level inputs (speaker level from rear speakers). Final config will use rear channels as subwoofer channels and fronts as.. well, fronts .
Speaker cables were also laid out. I used Professional grade Cordial HighFlex 4x4mm cables that were routed through the sills and up to the cubby holes were crossovers will be located. from the cubby holes to the OEM ampplifier location I also routed Cordial 4x4mm cables.

front left cables going in:



and to the cubby hole:



And the subwoofer (RCA Cables + remote hidden for now)



Subwoofer remote accesible from driver's seat (albeit not quite easily):



Final look of subwoofer install:



And with the seat in it's nornal driving position - subwoofer is fixed into place:

 

[monkadill]

NIce post - thanks