E30 Audio Overhaul - My Project Details

[StereoInstaller1]

Setup looks amazing bmwman91

But i have a question for luke.



Let me get this straight...
So when you're installing a new deck to an e30 you reuse the old speaker wiring but in a proper non shared ground setup?

Hmm, i might have to try this myself.

-Cam

The speaker wiring from the amp to the speakers is not any kind of shared ground, and depending on the car there is sometimes only the fader wiring that is shared ground. Dig into a couple different cars' wiring diagrams, it is just bizarre.

subscribed.. Take lots of pics of this install!!!

I always thought with the cd43 that you only needed the + speaker wire and you were supposed to ground out the - on the RCA to the CD43s ground???

Will not matter on the input of the 6XS. Audiocontrol is smarter than that.

I would likely do the chassis ground for shield, but that has just become my norm now.

[Spaz]

The speaker wiring from the amp to the speakers is not any kind of shared ground, and depending on the car there is sometimes only the fader wiring that is shared ground. Dig into a couple different cars' wiring diagrams, it is just bizarre.

Ah sounds pro :D

[bmwman91]

subscribed.. Take lots of pics of this install!!!

I always thought with the cd43 that you only needed the + speaker wire and you were supposed to ground out the - on the RCA to the CD43s ground???

You DEFINITELY don't want to run any of the outputs to the ground. It has a DC offset of ~1/2 the battery voltage, plus the audio signal. The output driver would blow faster than a hooke....nevermind. Just don't do it lol.

[StereoInstaller1]

No, he said use the chassis ground as the shield on the RCAs...not short an output to ground.

[bmwman91]

No, he said use the chassis ground as the shield on the RCAs...not short an output to ground.

Aaah haha, yeah that sounds about right.

I have been making more preparations for the build. I received my tweeter pods & have been "cleaning" them in preparation for the tweeters I want to install.

To get the stock drivers out, use a small flat-blade screwdriver to pry the metal body out. You can crank on the plastic ring around it & mess it up because it is coming out next.


Getting the ring out is a little more work. Needle-nose pliers are a good tool for the job. Grab the ring from behind & lever inward to break the glue holding it into the pod. I found that getting it nice and hot with a blow drier helped soften the (ancient) glue. Just work carefully, and once the glue cracks in one or two places you can probably yank it out.


I used some small cutters & a Dremel with a flexible sanding disk to remove the inner molded ring. I wanted the inside surface nice and flush for the installation of the tweeter.


A little closer...


Don't judge me...engineering is a disease. Sometimes I catch myself folding a towel before tossing it into the hamper. Anyway, I want this planned out 100% before buying drivers.






The important dimensions are added. That inner lip is best cut off. If you don't want to cut it, it sticks up 1.4mm past the inner surface, and is 1mm thick.


Just in case you were wondering how much room you get (depth), here are the important domensions on the tweeter. I am not sure how much more space you have beyond this, and I have no intention of modeling the whole door!


So there I am for now. I just need to figure out if there is any way to get a 75mm deep woofer into the front cutouts. I measured 69-73mm from the mounting surface. Spacers are not really an option since I want minimal interference with the covers. Does anyone know if there is anything behind the metal? I can easily "engineer" some additional depth with a 2x2 & a big rubber mallet, as long as I am not hitting the fender or something.

[bmwman91]

I emailed Audio Control asking them about running the CD43 outputs directly to the 6XS. The inputs are unbalanced, so the device only uses the "+" input, and the "-" input runs to ground. This means that the connection to the CD43 will ONLY use one of the outputs per channel, and the 6XS "-" input will be grounded to the chassis. If you run the "-" output from the CD43 to the 6XS, it would basically short to ground.

They also mentioned that I could use their level converter to take the CD43 inputs (+ & -) & run that to the 6XS, but I don't really see the point if the level converter is just turning the CD43 outputs into unbalanced ones, since the 6XS could just use one output directly. The 6XS can handle inputs of up to 15V before clipping occurs on the input stage, so I do not have any qualms about running the CD43 to it directly.

One advantage to using the level converter is that running the differential signals to the trunk would improve noise immunity. Then I would only be running an unbalanced signal a few inches from the LCO to the 6XS. I can always add that later on.

[318Joe]

A little closer...

Thanks for the writeup. Could have used it when I tackled my tweeter replacement.

I don't know if it changed over the years, or if it was the luck of the draw, but only one of my tweeter pods had that lip. The other had that lip attached to the tweeter, and had no retaining lip on the pod shell (top):

[StereoInstaller1]

What tweeter you planning? Most I have done have used that ring you cut off to prevent airflow from being disturbed (and all kinds of resonances and reflections) by a gap right at the throat of the tweeter diaphragm.

Kinda nice calling Audiocontrol, huh? I swear, every time I call I get the same thing. Helpful, courteous, professional but fun. I wish to hell they had a place to put me in that company, I would love to work there. They certainly could use an installers touch in some of their products, but everyone there always seems so cool.

I am glad they validated just exactly what I said, too. Chassis ground the shield, only use the center pin, 13V input max...easy, quiet, noise free setup. I have done quite a few installs using this same technology in many cars...some you can't, but generally, pre-1999 BMW works flawlessly. I bet I have done over 50 BMW cars alone set up just exactly like that...works great.

[bmwman91]

What tweeter you planning? Most I have done have used that ring you cut off to prevent airflow from being disturbed (and all kinds of resonances and reflections) by a gap right at the throat of the tweeter diaphragm.

Kinda nice calling Audiocontrol, huh? I swear, every time I call I get the same thing. Helpful, courteous, professional but fun. I wish to hell they had a place to put me in that company, I would love to work there. They certainly could use an installers touch in some of their products, but everyone there always seems so cool.

I am glad they validated just exactly what I said, too. Chassis ground the shield, only use the center pin, 13V input max...easy, quiet, noise free setup. I have done quite a few installs using this same technology in many cars...some you can't, but generally, pre-1999 BMW works flawlessly. I bet I have done over 50 BMW cars alone set up just exactly like that...works great.

I will be using a Seas tweeter, listed in the first post. I am definitely concerned about reflections & resonance, so I will be "making" it fit. It looks to have a pretty thick plastic cover on it, and I will be sticking that into a lathe & modding it. The mounting flange will go away, and I will make a step in it so that it will fit into the pod like the stock one did. I will either glue it in, or maybe go nuts & thread it & the pod and then use a little LocTite. The M.O. here is "overdone" so I will probably try to thread the first 4mm or so. I would like to make this serviceable if the tweeter blows.

AudioControl scored points. They had an engineer write a very intelligent response.

Yup, I will be making signal connections like you suggested. I won't argue with your experience since I don't have any of my own here.


Today's updates:

- Fixed the drawings in post 1. Somehow I deleted the block with the CD43 in the signal drawing. So I fixed that, and updated the signal/ground wiring to the current plan.

- I ordered the drivers from Madisound. I updated the OP to list the ones I purchased. Now I am committed to fitting 75mm deep woofers up front, whether I like it or not lol.

The sub ended up being a low-profile unit from SB Acoustics for a couple of reasons. For one, I want to be able to fit all of my climbing gear & pads in the trunk still. Second, the SBA sub has ~90dB sensitivity and a nice flat response. The SP10 & WQ-1858 had bumpy response curves & only had ~82dB sensitivity & the woofers/tweeters have ~90. That would have meant running 8x the power to the sub to keep the system response flat (or 1/8 to everything else).

According to WinISD, the SBA sub I chose will have an f3 at ~33Hz with the E30 trunk as the enclosure (all theoretical of course, reality will probably be a lot different). That should be more than enough bump capacity.

[Schnitzer318is]

Subbed.... carry on. :thumbsup:

[cobraken]

Neat!

[BeirBrennerE30]

Wow... this is serious.

[bmwman91]

Wow... this is serious.

srsbsns, definitely

[StereoInstaller1]

According to WinISD, the SBA sub I chose will have an f3 at ~33Hz with the E30 trunk as the enclosure (all theoretical of course, reality will probably be a lot different). That should be more than enough bump capacity.

Wait...are you doing infinite baffle?

[bmwman91]

Nah. Not enough room. :p

The trunk is pretty big, but I don't think that it is large enough that reflections can be neglected. That, and the surface the sub is mounted in is really pretty small, and it fires into a small enclosed space.

I will be using the trunk as the enclosure, though. I want room for my climbing gear & other stuff still, so I am not building a box for it. It was just a matter of finding a sub that has large excursion (large box = small mechanical damping) and has a reasonably low Fs.