[mike_b]

I have been busy working on my car's sound system for about 2 months now. Here are some of my posts from one of my regular sound forums in South Africa.

So the stock sound satisfied me for about 3 minutes....
The standard sound in the E90 is a pair of 4" mids in the front doors and a pair of 6.5" subs under the front seats running off the front channels of the HU and some 4" mids on the rear shelf running off the rear channels of the HU.

First step was to replace the 4" mids with a set of DLS K4 4" splits. These splits are designed to run off HU power and that's what I planned to do with them.

Then for the lows I decided to use my existing RF amp and subs. I wanted to use both the 10" P1's but only ended up using one due to the constraints of getting bass into the cabin.

On to the pics:

First off, the window frame covers did not have space for tweeters, so I bought some spare ones from a scrapyard and went to work on those. I was going to flush mount them like this...


I didn't like the way it looked so I tried using fibreglass resin and moulding a tweeter pod


This is what it looked like before


After


Problem was that I didn't use fibreglass matting, just resin and body filler. They weren't strong enough so it was back to the drawing board


After being sanded down and fibreglassed with about 2 layers of matting


The standard BMW 4" mid


Mounting plate for the DLS mid


Behind the door card


The DLS mid mounted


Then the cutting starts. The centre armrest folded down and the plastic trim backing removed. This just leaves a carbon fibre like firewall




I got some ideas from Vaux and Kevin and decided to build a sealed enclosure and fire the sub straight into the cabin






I made a mounting plate that screws onto the firewall


Rubber tape seals off the plate so that the front wave of the sub does not leak into the boot


Then the front plate of the sub box can be screwed onto the mounting plate

[mike_b]

I then made some changes to the original upgrade:

Sold my RF sub and amp and got a Hertz Energy 10" sub and JL Audio e4300 4ch amp. Also changed the splits from the DLS K4 to Focal Polyglass 165VR3 3 ways.

So the setup as it stands now is the factory head unit up front, the JL amp running the splits on 2 channels and the sub bridged on the other 2 channels. I'm using the SVEN2 LOC tapped into the front channels off the HU and the rear OEM speakers are faded out. I must mention that not one factory wire or pannel was cut in this install - except for that firewall behind the rear seats

OK, here's some more pics.

This is where the factory subs are located


The factory sub in it's enclosure


The sub fires down into the enclosure and is ported into the body of the car




After removing the factory sub, I made a mounting plate for the Focal 6.5" woofer






Pic of the Hertz ES250


The amp goes under the trunk floor in the storage bin. I still need to mount it and neaten up the wiring


This is the space where the Focal woofers are mounted - under the front seats




The wiring for the mid and tweeter into the doors








I still have a few pics to upload. The door cards are not on properly and I'm experimenting with the tweeter positions. So far they sound best playing on axis.

[Menno11]

Looking good Mike, good job for a DIY!

Where did you run the speaker cables and the signal cable to the back? How did you get them into the boot? I would like to see what the Hetz sub looks like through the armrest and the 6.5" under seat in its final position (pics!)

[Menno11]

Hey Mike,

What are you doing with the old DLS K4's?
I would be very interested to buy them from you if they run well off the HU!

[mike_b]

Hey Menno, I'm thinking of keeping them. The tweeter on the Polyglass set is quite harsh at high volume. I might try the DLS tweeter again if my other plan does not work.

I can organise a set for you though. I paid R750 and the main dealer is actually in PE.

[Menno11]

Yeah, that sounds quite reasonable. I wanted to install my Cerwin-Vega V-max 5" splits, but they need more power than the head unit can supply.
How does the HU handle the K4's at high volume?
How did you get the speaker and signal cable past the back seats to the boot?

[mike_b]

the K4 handles the HU power all the way to max volume. In fact they could handle more. Something about the standard HU - it does not put out a lot of power and I would guess that at max volume there is very little clipping aswell. The splits sound nice at max volume on the HU - could be a bit louder though, especially if you drive with the windows open.

To get the cables into the boot, I removed the rear seat bottom and ran a lead wire through the passenger side corner of the boot . It comes out just under the rear seat backs in the corner. It was not difficult.

[kaigoss69]

Nice install indeed! Could you comment on the following:

1. The level of mid bass coming from the 6.5" Focals, since they are under the seats and midbass is somewhat directional. I mean do you jsut feel it in your buttcheeks or do you actually hear the midbass as well?

2. How did you isolate the midbass frequencies?

Thanks

[Random456]

Woh, nice job. What does the sub look like on the inside of the cabin when the backseat armrest is down?

[mike_b]

Hey Random, the sub looks pretty cool from the inside of the car. I still need to fabricate a cover for behind the armrest. There is an oem plastic cover that goes there but I removed that and am going to replace it with a cover that allows the sub to be seen. I've been a bit busy lately and as long as there is music, there is no urgency.

I have also replaced the JL amp with an Audison SRx1 and an Audison SRx4.

Kaigoss, the midbass is actually quite decent. You are right about the frequency range being directional, but for some reason it still sounds like it comes from dash level. I think it is because the oem speaker enclosures are ported into the side sill. It sometimes feels like the midbass is not integrating with the higher frequencies. That could also be because of the excellent focus and imaging of the speakers. The instruments are easy to identify and place.

On your second question, I am using a Power Acoustic 3 way active crossover. At the moment the front speakers are running off the 3 way passive crossover, so I use the active crossover to high pass at 70hz/18db. The passive low passes the midbass at 400hz/12db. I am toying with the idea of running the front stage fully active.

Here's some updated pics:

[Menno11]

Hey Mike,
Your install is looking super sweet man!
Is that a distribution block next to the right amp? Are you still gonna make a cover plate for it all or you gonna show it all off?!! it looks like you got the template for the back seat just right.
Where did you get your remote signal wire?
Keep up the good work man!

[mike_b]

Hey Menno, thanks man.

No cover plate - amps need to keep cool. Yeah, that is a distro block, from Audison. Audison make excellent quality products, their range of accessories is called Audison Connect.

I am using an SVEN2 from Stinger. It's a hi-low converter with built in remote out. Thing is, now with the new amps, the SRx4 has high level inputs with signal sensing remote turn on and a remote out for other amps. So I actually don't need the SVEN. The amp is made for oem integration.

I have been having issues with the amp that drives the 3 way splits. When I was using the JL amp and now with the SRx4, the amps overheat after about 45 mins of max volume playing. I have tried adjusting gains up and down. I have measured the load on the amp to be 4ohms. I don't get this issue with the sub amp. I am out of ideas. I'm not sure if I'm clipping the input signal or if the amps take strain powering a 3 way setup. If I set the gains to low the volume is inadequate. If I go to high, the speakers distort at max volume. If I set it just right, ie: just below the poit where they distort, the amp overheats.

Anyone had this problem when using an SVEN or the Professional CD player?

[Halston@bsw]

They look a little deep but I assume those DLS mids end up fitting?

[Menno11]

Hey Mike,
Can you not boost the input signal to the amp from the SVEN? that way the amp doesn't need to work as hard to get the volume out. Otherwise maybe look at a line driver?

[lkn]

I'm very impressed. great job!

[mike_b]

@Halston, Yeah, the DLS mids did fit.

@lkn, thanks man.

@Menno, I thought about a line driver... I actually thought about a 360.2
I'm not sure if that is the issue though.

[Halston@bsw]

Good work!

[Random456]

Originally Posted by mike_b

Hey Random, the sub looks pretty cool from the inside of the car. I still need to fabricate a cover for behind the armrest. There is an oem plastic cover that goes there but I removed that and am going to replace it with a cover that allows the sub to be seen. I've been a bit busy lately and as long as there is music, there is no urgency.

Awesome, man! Can't wait to see more.

[mike_b]

Thanks Halston and Random, I'll keep the updates comming as it progresses.

[yunus]

hi mike,
where did u pull the signal for the amps from ? straight from the hu or do you have the hifi system with the amp in the boot ?

[mike_b]

Hey Yunus, I tapped into the speaker cables for the underseat woofers for signal. I am using a Stinger LOC to convert the speaker level to RCA level. I had the standard 6 speaker sound system, not the hi-fi with amp.

[yunus]

thanx for reply,

how did you then get the amp signal back to the standard speaker wiring ? or did you run new wires to the replacement speakers ?

i am looking to connect an 4 channel amp to the standard wiring. without the hassle if completely rewiring ,just to add some quality and volume to the subs. i have replaced the door and shelf speakers with the infinity 4inh, which made a huge difference to clarity already . i think the amplification will do what i need it to. i am just looking for an easy way to do this . any ideas ?