BMW E60 sq build (Helix/Ground Zero)

Thought I might make a small build thread on a E60 I'm working on for a friend. The owner had a budget set in mind, and left the rest up to me. She is fond of rock music, and I don't think she has ever heard a "proper" sound system, so this should be fun!

But to set the stage here, this car was bought used, and some previous owner had made some "upgrades" himself. The car has a base sound system, meaning just mids in the doors, no tweeters, and 6,5" underseat midbass/woofers.

The "upgrade" was at first sight a JBL 2x12" premade ported box (2ohm) running off two bridged channels of a noname "4x300W" amplifier (2x25A fuses), going into protect at the first heavy bass note. As it is no way capable of 2ohm mono :p And a 2005 BMW base head unit with a broken CD mechanism, meaning the only audio playback was from a DAB+ adapter (digital radio) using the aux input. (Norway has switched fully to digital radio now, and the FM transmitters are basically shut down over here, just some minor local stations on a handful of weak transmitters.

So that was the starting point.

Now for the upgrade. Starting fresh with a new headunit, I bought a 2din fascia kit, and a Alpine Halo9 headunit for the car. Amplification and sound processing will be in form of a Helix M Four DSP to run the front components, and a Ground Zero GZCA 3-0SPL M1 monoblock for the subwoofers. Way overpowered, but I had it laying around and it will only be run at 2ohm.

Front speakers are Ground Zero BMW plug+play upgrade speakers, 4" components in front doors and 8" woofers under seats. Subwoofers are 2x Helix Q10W in a sealed enclosure.

Progress pics coming shortly!

This sounds like quite an upgrade. It's a shame nice cars like this get "upgraded" in such poor ways. Really looking forward to pictures.

I can start with the least interesting bit, swapping out stock speakers with plug+play upgrades.

However (as always) it wasn't as plug and play as you would expect. As it turned out that the previous owner also had done some more upgrades. Swapping the OEM 6,5" underseat woofers with 8" Match drivers. But he had just connected them to the HU, so if anything the output was probably much less than stock, since these require more power which they never got. And on top of that, two channels from the 4-channel amp in back was still unused? :D Some people..

Anyway, this were mounted under the seats:
Attachment 15584

But were replaced with these:
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And new door speakers. We ran all new cables for the doors and woofers from the amps in back, 10ga 100% ofc.

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This part was incredibly easy, since I got the wrapper/tint guy where I'm doing the install to do it :D He's an expert at pulling apart cars and know all the ins and outs on most cars to take things apart without breaking anything, very handy on 15+ year old cars!

Ok, now over to the more interesting part, the actual build.

Unfortunately, this particular car did not have folding rear seats, nor a ski hatch/passthrough (both options on the E60 model). That means that the trunk is sealed off from the cabin. But luckily not with a steel wall, just a plastic rear wall + carpet. So we took care of that.
Attachment 15588

Good passthrough, will finish it up with a trim ring. Still a plastic cover in front of this, between the wall and foldable armrest. Will make a opening in that as well, and some kind of grill to protect the subwoofers.

Removed all the layers of carpet and styrofoam to get to the botton of the spare wheel well. It's huge! But as it had some control box (for the rear parking sensors), and the depth wasn't really required for the amp rack etc, it was just cleaned up and put back. More than enough room in the storage compartment (top half of the spare wheel well).

Now comes the fun part (for me at least) since I have access to a range of fine machinery at the place the install is being done. CNC router, laser cutter, signage printers, vinyl cutters etc. I took some measurements of the space available:
Attachment 15589

Measured from the bolt in the center, that holds the spare wheel on cars equipped with that, and guesstimated a layout in the design software based on that. Then cut out the template on the vinyl cutter:
Attachment 15590

Had the shape pretty good, but saw that it didn't lay flat as there was a slightly raised section in the bottom left corner. So I adjusted the files a bit, made the center cutout smaller, and made this base from 19mm PVC on the CNC:


Attachment 15591

Now it can be clamped down and secured to the car with just a nut and washer for a secure mounting.

Def interested in your progress, especially how you finish the passthrough. I too have an E60 so I want to steal take notes and study your design lol

How difficult was running the wiring into the doors? Wondering if you had to drill out the connectors

For me it was super easy, I just told the guy who installed the speakers to run new cables as well! ;) But that aside, it wasn't too hard, it's just a single 14 awg cable run through the OEM harness, I can try to take pics next time I'm at the location.

Had to splice some cables under the seats though as they had cut the OEM midbass connector because the Match drivers had regular screw terminals. Luckily the GZ door component set had a full crossover set, including for the midbass drivers. Since this will be run with active crossovers, we could snip off the BMW connector on the crossover and use it for the new speaker wires going to the back. Since the GZ underseat drivers use the BMW connector for plug+play install.

Here are the different components that make up the false floor, four layers of different materials and thickness.

Attachment 15677

Will be looking something like this put together:
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So far only the second layer from the top has been made, this is the main structural part, made from 19mm pvc.

Next on the list was to make an amprack of sorts, this first version is more of a mockup to see how the final one will be made. Made a quick design in adobe illustrator and sent it to the cnc router.

Attachment 15715
Made from 19mm pvc, same as the floor board/base.

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Amps will be placed more or less like this, had to find out where they were going to be placed when centered left/right in the trunk. And if they interfered with the OEM threaded rod that secures the spare wheel when installed.

Some close up shots of the routered pieces:
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I see where I need to make adjustments for v2/final design, and also found out that the placement interfered with the threaded rod at full length, so that is now cut down to suitable size. It's new purpose is only to secure the base plate anyway.

Attachment 15722

Printers that can print directly on a sheet of MDF are pretty cool.... ;)

Some more progress pics.

This is the speaker baffle while an image is being printed on the back side of it (inside of enclosure). Since the mdf is greenish brown, it is first printed several passes of white ink, so the top image comes out with the right colour hue.

Attachment 15727

Didn't take pictures of all the steps, but here is the box after putting the first 5 sides together, and checking fitment of acrylic bracing (nice tight press fit here, will be bonded to the box later). Half inch acrylic for bracing and trim piece.
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Some cool things going on here

Wow .. so very nice!

Thank you! :)

Have to say this is my most ambitious enclosure build yet, taking advantage of available machinery at the shop. It's also a good learning experience in operating the machinery, so win-win in that matter.

So the plan for the enclosure was this: 40 liter sealed (1,4 cu ft), made from 22mm MDF with bracing and rear wall insert made from acrylic. Printed design on visible inside panels (baffle and sides), acrylic mirror on bottom, and white interior lighting. Didn't plan for any special exterior finish since all but the rear "window" will be hidden behind trim panels. But more on that later ;)

This is the enclosure mostly put together, after printing the baffle I masked it off and spraypainted the walls of the speaker cutouts with black paint, in case part of this would show after the woofers were installed. Routered some pieces of mirror acrylic on the cnc, to be placed in between the bracing. Fastened these with bonding adhesive (Tec7) to the mdf. Also the lighting is installed here. I used a led-strip from SloanLED, a supplier of lighting solutios for signage, with a 50k hour rating. This is pro stuff with a price to match, but it's not easy to just replace them after the box is put together and installed. So no random ebay LED in here ;)


Attachment 15743


Subwoofers installed, these are 2ohm DVC subs, so they will be wired in both series and parallell for a final single load of 2ohm. Found it to be cleanest just to wire each voice coil individually and run 4 runs of cable (each with positive and negative) and do the connecting outside of the enclosure. Instead of wiring each driver in series inside of the box.

Also, the rear wall you see here in 22mm mdf with recessed cutout of 11mm, where the 20mm acrylic will be placed and bonded. Then a mirrored piece will be placed on top, so the acrylic will be sandwiched between two pieces of 22mm mdf. 11mm recess to make place for 1mm of bonding adhesive on each side.

Attachment 15744

Wiring came out pretty clean when viewed from the back:

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And to personalize some part of the install to the owner, I took the motto from her licence plate frames and made a decorative ring that is placed on the back plates of the subwoofers:

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Turned off the lights in the shop and adjusted the camera settings so the picture looks close to what it looks like IRL:

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Pretty happy with this, you never know if it will turn out how you imagined in your head before starting to build, but this was surpassed the imagination.

Wholly moly! That has got to be about the cleanest and most awesome enclosure, ever.

Thank you for the kind words :) Cleanest coming out from my workbench, that's for sure!

Even though it will be hidden behind trim panels (and a non-folding rear seat), I really felt like it should have a nice finish on the outside as well. Especially since the upcoming owner maybe wants to enter some car audio events down the ilne. And when the trim panels are pulled down to inspect how the box is secured, it wouldn't look good with bare mdf, especially since it has some paint overspray from painting the inside of the speaker holes etc.

Also, I had to remove the plastic trim rings around the woofers, as they are placed so close that it would have interfered slightly.

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So I designed a trim ring that slotted neatly on top. Made from 19mm closed-cell PVC foamboard. This material is close to MDF to work with. Less density, but waterproof. And has a nice finish.

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Front of enclosure could be visible (depending if I make a see-through or not passthrough in the armrest trim piece), so decided to make a face plate from 3mm dibond (composite sheets made with a plastic core and alloy skin on each side. This particular has a matte silver metallic finish on one side, and brushed aluminium on the opposing=. Chose the latter as the visible side.

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Was going to just use this on the front and back (with cutout for window), and cover the top, sides and bottom with carpet. But really liked the finish, sooo....

This happened:
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Last addition to the enclosure before going in the trunk.

To raise the enclosure off the trunk floor (I want it a bit higher up, close to the underside of the rear shelf), I made some PVC spacers. With these installed, it also allows the new false floor board to slot underneath the enclosure, and provide enough clearance to lift it out to access what is underneath.

So I made these spacers about 2" tall:
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A quick test fit in the car:

Attachment 15781
False floor slotted in place, but a very tight fit, so I might have to trim them down just a little bit. In the end these will not rely on a press fitment to stay in place, but I will make a frame around the perimeter of the floor board in the wheel well that will support the false floor. Keeping it in place either with magnets or with 3M Dual lock industrial "velcro".

Same with the shop lights off, but still the OEM trunk light on. This will be disconnected, and rather be used as a signal to turn the enclosure and "mood" lighting on and off.
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Just a mockup here, but will get a bit sturdier brackets that will be bolted to the enclosure, and this brace bar underneath the rear shelf. Will install rivnuts in the brace, so the enclosure can be installed and removed how many times one would like.

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That concludes today's broadcast ;)

https://youtu.be/mfaqkzlCR9w

Maybe this should be the finishing touch, but still a lot to do :)

Beautiful work, mate! The owner should be super excited and pleased with the result! :thumbup:

Hopefully she will be :) And thank you!

Made the trim panel for the enclosure yesterday, after a bit of trial and error getting the side contours right.

Still have to upholster it with carpet, but this is the bare form:

Attachment 15796

From the back it looks like this. Was out of 19mm pvc, so made a sandwich with 10mm scraps, had to use different colours. Oreo edition. (or Stormtrooper, sounds more impressive? :)

Made grooves around the perimeter that the carpet can tuck into, channels for the LED-strip including wiring, and recesses for neo magnets that will be used to keep it in place, while being easily removable for service etc.

Attachment 15797

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Ok, so I'm a non-professional consumer, living in Norway.

Do I turn myself in to the Norwegian police? US Embassy? Prisons in Norway are pretty nice, I'll take my chances here. I could even put in a good word for the retailer in the US so they could do their time over here

Impressive! Youre putting in such nice work

Do you have any pics of what you did with the pass through?

And what is the design philosophy regarding the sealed box. If youre cutting the seats for a pass through, did you determine sealed is better than infinite baffle?

Well this took its sweet time, but the build is finally done and the car is delivered to its owner :) Been working on this off and on between the projects on my main job.

Changed the setup a little bit in the end. The owner wanted to retain the BMW I-drive functionality (even though this does not do much when you take away the audio control settings), and the idrive screen/control wheel is controlled by the OEM head unit. So we agreed on ditching the Halo9 install, keep the idrive, and use a phone/dap/tablet etc as the audio source, since she 99% is using spotify for playback anyway.

And then the most convenient way was to use a Helix bluetooth streaming module. But since the M Four DSP amp does not (yet) have an option to fit such a module, I swapped it out for a regular M Four, plus a Helix DSP Mini with HEC BT module. This setup only use 5 channels anyway, so no need for the 10 dsp channels in a M Four DSP.

I installed a Helix URC.3 controller on the side of the centre console, to control both main and subwoofer volume.

I do have some build pics from the trunk build, but at first here are some pics of the finished trunk:

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I'm equally bad at editing as filming, so it really evens out :D

But put together the small clips I made on my phone while building:

https://youtu.be/k__le6snHrw

Beautiful acrylic and custom vinyl work... Was it a PITA applying the "stickers" to the back of those magnets so symmetrical? I am supper bummed that Helix has decided to discontinue the Q line of subs, hope they replace with something better and not take steps backwards...

Definitely a show piece worthy install!!!!

Thank you thank you :)

Actually the accent rings are laser cut/engraved plastic, so they are pretty thick and rigid, they are fastened with industrial double sided tape. It's made with special dual-colour engraving plastic (white bottom layer, black top layer), so the laser burns away the top layer to reveal the bottom layer/color.

Not too hard to align, but then again aligning and mounting stickers/graphics/signs has been my trade for the last 20 or so years.

Regarding the Q series subwoofers, I've heard talk on forums etc for "years" that at least the Q15W was discontinued, but they are still in stock over here, and I mentioned this as recently as earlier today when talking on the phone with the local Helix distributor, he had heard no such thing from AF themselves.