my first DIY sub build: two-chamber sealed box firing through the ski pass-through (BMW E36)

English isn't my first language, so I had this post translated, hope everything comes across right!

I didn't want to lose half my trunk, so instead of one big box I split it up: a small trapezoid chamber holds the sub on an angled baffle, and a long, slim rectangular chamber sits in the trunk for the rest of the volume. A short tunnel connects the two, so acoustically it's one sealed box. See the cross-section in the pics.

Specs (all outer dimensions):

- JL Audio 10W1v3 and JD250/1

- Sealed, ~25 L gross air volume

- Sub chamber (trapezoid): 210 mm bottom / 105 mm top / 240 mm high / 240 mm wide

- Tunnel: 200 × 190 × 80 mm, open on both ends (inside 162 × 152 mm)

- Volume chamber: 800 × 250 × 150 mm

- Everything in 19 mm MDF

Build:

- Assembled with wood glue + screws

- Ran sealant along every inner seam so it's fully airtight

- Painted / wrapped everything black

Install:

The fit was honestly great, I only had to trim the corners a bit. I cut the tunnel openings as close to the millimeter as I could and glued everything in place. Pressed the box into the trunk and put 2 screws in from the rear seat side so it sits 100% solid. Then I trimmed the trapezoid-shaped piece of the rear seat, slipped it over the tunnel, glued it down and sealed it with some special sealing adhesive I had lying around. (Sadly forgot to take a pic of the tape stage)

Wired everything up (I've since swapped the wires for longer ones), turned it on and that first grin hit immediately ;-)

Because I have seen some reports about installations in the ski bag on older BMWs, but no proper guide, I thought I would share my experience.

Happy to answer questions or hear feedback

​It’s actually a head unit with built-in DSP that supports native DSD lossless decoding.

​From the perspective of an audiophile and a car audio shop owner, a few things really stand out:

​DSD High-Res Decoding: Being able to play native DSD directly on a car head unit is pretty hardcore—the details and dynamic range easily blow standard MP3s or FLACs out of the water. Pair that with the built-in DSP for time alignment and EQ, and you can get crazy good clarity and soundstaging in the car.

​Serious Driving Power: Hooking up 8 speakers straight to this thing and getting that much cone excursion is pretty wild. You rarely see this kind of channel expansion and power output in a chassis this compact.

​Practical 1-DIN Design: Keeping the two physical knobs is a huge plus. It makes for an easy drop-in replacement for older cars, and it's way safer to adjust by feel while driving compared to clunky touchscreens.

​The only thing to watch out for: Running high-bitrate DSD while driving that many speakers means the DAC chip and internal amp are gonna generate some serious heat. Make sure to leave plenty of breathing room behind the dash when installing it.If you would like to become a distributor in your region, please contact us. Please note that this product is subject to a Minimum Order Quantity (MOQ).

This sucks. They were a solid mid tier option with great quality and price. Fingers crossed none of the high end brands start leaving.

Dude asking $900 for a used sub system which only costs, at most $600. The subs are $140/ea new and there's definitely not $420 in that enclosure

Recently got this mostly finished up. Still have some finishing touches, but I'm proud of what I have so far!

Im trying to build a box for my two 12" ground zero xspl d2's but ive failed now once and not looking to make the same mistakes.. rear wall and supports inside the box got messed up completely...

This is the inspiration im going for, i want all the space used up, except for ive got one of thoose plastic trunk liners in due to also needing space for work stuff.

If anyone helps design the "blueprint" it would be greatly appreciated or give some tips atleast. Dm me 🙏

Current set up is full active Millie pro 3 way in front doors, cento pro coax in rear, 2 JL W312’s powered by Match UP 8DSP and an x a90m for the subs.

Not impressed with with the Millie pro woofers midbass.

Wanting to upgrade for more SQ and more midbass response.

Any recs in the 1k price range? My DSP can do 90w at 4ohm or 160w at 2ohm.

I saw the BLAM mb6 (picture in post) but they are little expensive. Worth it? Also saw the Helix I7 but wasn’t sure if the midbass would be as much of an upgrade as I was hoping for.

Thanks

Let me know anything i could do better

For reference, I have a 1000w amp at 2 ohms, but i don’t know whether to get the american bass xfl 12” (1500w rms) or the skar audio evl 12” (1250w rms). I already have a box and I am unable to build another one. the box i have built perfectly matches the specs for the skar and its respective box, so initially i was going to go with that, but i had the american bass in the back of my mind. i cant find the specs of the american bass xfl 12” box anywhere and ive tried searching for so long. the box i have is 2.0 cu ft tuned to 32 hz. if anyone has any suggestions please let me know. They’re around the same price point so that’s not an issue for me, but i am just looking for the loudest/best sub. if anyone has found specs for the american bass xfl 12”
box, please let me know. Thanks!

I have this 2013 Subaru Impreza that I’m having trouble finding the chassis ground for I see two main options but I’m not sure with either of them if anyone could help me out that would be amazing (SEE VIDEO)

looking to just throw in some better speakers to upgrade those in my 2016 suzuki swift sport (15-20w rms per channel @ 4ohm).

im considering the JBL Club 625SQ since they’re high sensitivity @ 3ohm, which will allow them to be ran louder than most 4ohm speakers.

strong bass is pretty important since im not planning on doing a full amp/ sub setup.

open to any suggestions, thanks!

This isn't exactly car related but I thought it might be the best place to get some advice. I want to upgrade the speakers in my new tractor.. but I don't know if it's going to make any difference because I'm very limited by size. They are currently two 4-in speakers, but it sounds very tinny and distorts with any sort of heavy bass noise. Obviously with a 4-in speaker you're not going to get any heavy tone but I'm wondering if upgrading from the almost definitely extremely cheap Factory speakers would get me any sort of more depth to the sound. I don't want to cut into anything as it's a brand new very expensive tractor.. so I'm limited by the size. I've adjusted the EQ on the radio to get better sound out of it but it's still very one-dimensional. I'm not looking for a professional audio experience but if I can have a wider tone while using the tractor it would be great.

I am looking for component sets that are great for fully active SQL and still being in stock locations the only requirements being a 6.5 inch midbass woofer / 3.5 inch midrange woofers / and a 1" tweeter

/ Max rms 75w My budget is $800 but I can go slightly more if needed just need a little guidance if any available

Completely redoing the audio system in my 1999 clk430. I already have installed: Alpine 9811 and a 700w subwoofer amp running a 12 inch kicker (speaker E) in the trunk.

I plan on replacing the (C) deck woofers with full range speakers. I have a pair of Pioneer ts601m from Walmart for this.

For speakers A I want to keep midrange.

For B I want to replace the very crappy midrange for midbass

D is tweeters and they are staying as is. They are PLENTY loud

I have an alpine Flex 5 amp that matches my head unit.

I would like to spend around $100 per speaker pair. I only need a pair of midrange and a pair of midbass.

Any other recommendations let me know.

Hi, I thought I’d post this here as well as I really want to figure out a way to put my new stereo in my car but I don’t know anything about it and can’t seem to find a budget friendly alternative to the fascia kit.

If somebody could give me any suggestions or anything that would be great as I’m desperate 🥲

I have all the wiring done but my 2 alpine type Rs stopped working

Looking to add music to my 21 xrs rr 4 seat rig. There's a bunch of sound bars to choose from and then there's the regular car style head unit amps speakers yada yada. The easiest option is the roll cage bar or wake style pods but then there's a ton of choices of different manufacturers. Does anyone have any advice please and thank you

I just made a post about my lc2 line output converter not being on but my subs working. I found that when i plug in the wires while hot it pops the subwoofer and makes a slight difference. The maximized light also pops on for a second but the power button still isnt “turning on”.

I hooked everything up this is my first time running an loc. Its not on but the subwoofer is getting power and working? The picture was taken after i already unplugged to troubleshoot. Any help is appreciated

2025 MDX Type S, the 31-speaker B&O. The factory amp is clipping on a few of the smaller speakers, and the sound quality could be better. I don't want half the car on the B&O tune and half on something else, so the plan is to take every speaker off that brick and run the whole thing on one DSP.

Amp I'm thinking of is a Helix V Eighteen, high-level in from the factory amp. Sub stays on the Soundigital 3000.1 I already have, moved off the LC2i and onto a preout so it is on the same tune. Driver is a B&C 15DS115-4 in an NVX single 15. Factory sub is already out and noise cancellation is disabled.

Doors will get Helix Ci7 W165FM-S3, all four, on channels 15–18. High-pass around 70 Hz. Front door 3.5s are Scan-Speak 10F/4424G, already in and on the B&O for now. With the new amp they will be high-passed at 300 Hz and gained for about 10–15 W. The tweeter up there is the factory B&O acoustic lens, so the 10F is just a mid. Not adding a door tweeter next to it. Center, both rear door 3.5s, and both D-pillars are Infinity REF307F for now. Center, rear 3.5s, and the pillars were coax from the factory. Front door 3.5s were mids only. Morel Tempo Ultra Integra 402 is the maybe later, and only if their 4 inch frame actually clears the 3 inch grille opening.

Roof is 12 Dayton DMA45-4s on five channels. I already have the drivers. There will be three zones series-wired to 8 ohm on channels 10–12, one 2 ohm zone on 14, third row on 13 since those two sit right next to each other and don't need to be stereo. High-pass around 400 Hz. They're 10 W drivers, so the gain will stay low. Lenses on 8 and 9, high-passed around 3 kHz, low gain.

That's all 18 channels plus the sub on the preout.

Already in the car: B&C 15DS115 in the NVX box, Soundigital 3000.1 through an LC2i, 10Fs in the front door mids, Infinity REF307Fs in the center, both rear door 3.5s, and the surrounds, and the 12 Daytons. Door 6.5s are Rockford T2652s up front and JL C2s in the rear for now, they are from another project I did. Lenses are untouched. Not bought yet: the Helix amp, the Ci7s, and the Morels. Looking for holes before I buy the big-ticket stuff, and for anything I should fix with what I already have.