E30 Coupe Subwoofer Boxes - No Longer Available

[e30fix]

dam iv never seen this set up. Im in for one too when they become available again.

[lonestar22]

Any update on the dimensions or where I can get these?

[Metallated]

Also interested in replicating if no longer available ..

Is it just a basic wooden box?

[m5james]

Bump

[audiquattrot]

Not sure if this is the same guy but the link below has a guy that makes these in much better quality

https://www.instagram.com/p/BtNJUkdAjMb/?utm_source=ig_share_sheet&igshid=studtx91voka

[g.ruff561]

I’m in for a pair of these boxes that fit JL 6W3. One box for each side. E30 coupe. Can someone pm me builder info if available.

[hendrixvodu]

Wow what an awesome idea !

[Gregs///M]

The woofer is firing directly against the door cards lol. How do you get any sound through those door cards?

Also, how do you get around bass cancellation when you have two woofers firing directly at each other. The bass output will cancel each other out.

[ArtFoodBMW]

These boxes were a huge pain in the ass to make.. I maximized the space as best as I could, but these subs could use more space to get better sound. They were a great addition to a stock sound system, but if you good bass, I'd recommend a luke box design which is what I ended up building for both my e30 and e34 touring.

[ForcedFirebird]

The woofer is firing directly against the door cards lol. How do you get any sound through those door cards?

Also, how do you get around bass cancellation when you have two woofers firing directly at each other. The bass output will cancel each other out.

They only way they would cancel out is if one was wired in reverse. SPL would be increased with two speakers, even facing each other. It's actually common for people in stereo competitions to have multiple speakers on both walls, floor and ceiling of vans/SUV's with a hole facing the cabin.


As far as sound traveling through the panels, no different than them traveling through your back seat (like the lukebox design). If it's a true subwoofer, then it will probably have electronic/passive bypass so they are only playing the low tones.

https://www.youtube.com/watch?v=LBTw5978nJk

[Gregs///M]

They only way they would cancel out is if one was wired in reverse. SPL would be increased with two speakers, even facing each other. It's actually common for people in stereo competitions to have multiple speakers on both walls, floor and ceiling of vans/SUV's with a hole facing the cabin.


As far as sound traveling through the panels, no different than them traveling through your back seat (like the lukebox design). If it's a true subwoofer, then it will probably have electronic/passive bypass so they are only playing the low tones.


https://www.youtube.com/watch?v=LBTw5978nJk

Lol, you are crazy man. Woofers firing from the same plane will not have cancellation. Woofers firing at each other will have some sort of cancellation with the bass waves interacting with each other.

When you toss two pebbles in the water at the same time, do the waves get larger or do they mesh and cause disturbance?

I bet the SPL system in the video would be louder if the woofers were on the same plane not firing at each other. This is why some of the top SPL winners only have one woofer. Trust me, I've been competing in SPL and SQ competition for over 30 years in the manufacturers category.

[ForcedFirebird]

Lol, you are crazy man. Woofers firing from the same plane will not have cancellation. Woofers firing at each other will have some sort of cancellation with the bass waves interacting with each other.

When you toss two pebbles in the water at the same time, do the waves get larger or do they mesh and cause disturbance?

I bet the SPL system in the video would be louder if the woofers were on the same plane not firing at each other. This is why some of the top SPL winners only have one woofer. Trust me, I've been competing in SPL and SQ competition for over 30 years in the manufacturers category.

I have been out of the game since about 2000, but was designing isobaric, bandpass, and a mixture of the two boxes in the early-mid 90's. Not "that" crazy. Ever hear of Mad Mark's Hearse? I was purchasing from him when he was in his small shop in Bradenton, FL with a very similar box design to the one in the video I linked. ;) Going from memory he had something like 16 15" woofers in that thing with it's "bowling ball" paint job.



As far as sound waves, they are much like the double slit experiment. The only way they will cancel is if the speakers are reverse polarity. Again, it's a popular design to have woofers facing each other to increase SPL (see the video). Throw 2 pebbles in a pond don't create a smooth surface (ie cancel). There's too many reflective surfaces in an automobile - a car is nothing like a pond - maybe a small irregular shape box of water (full to the brim with water, at that, so sound is radiated in 3d, not a 2d surface tension). Sound is reflecting and absorbed by all the surfaces, and fully radiating in all directions, and many people use that to their advantage to cancel particular frequencies and add more bass/mid bass etc. Reflected waves can cancel, sure, but those cancellations cause higher peaks in some frequencies, but lower in others.



So, with this logic you speak of, and discussing sound waves in an e30, the kick panel speakers are useless since they are facing directly at each other? Or what about many other makes that put speakers facing each other in the back seat of a coupe?



Don't take this as an argument, not discrediting you age or credentials, but I do enjoy intelligent conversation - you are a pretty bright mind from what I have seen of your work/posts.


-J

[Gregs///M]

Speaking strictly in terms of sub frequencies, you do not want two or more bass generating speakers facing each other. The waves will cancel when direct at each other, although not completely. However, when facing on the same plane, those same two waves will combine. Its acoustical physics.

Aside from all the math and science, from experience, woofers in those pockets do not generate much bass, even the OP admits that. Especially with 8 inch woofers. One 10 or 12 in the trunk with a good amp will greatly outperform.

[ForcedFirebird]

Speaking strictly in terms of sub frequencies, you do not want two or more bass generating speakers facing each other. The waves will cancel when direct at each other, although not completely. However, when facing on the same plane, those same two waves will combine. Its acoustical physics.

Aside from all the math and science, from experience, woofers in those pockets do not generate much bass, even the OP admits that. Especially with 8 inch woofers. One 10 or 12 in the trunk with a good amp will greatly outperform.

Then how would you explain a classic high SPL that has 3 chambers. Two sealed (behind the speaker), with cones facing each other and a middle chamber that has a tuned port facing out - which will out-perfom two sealed enclosures facing the same direction? It's not much different than pulse tuning an intake manifold (or ITB's) to peak power at a specific RPM. You are using reflection and pressure/sound waves to amplify a specific frequency.



For instance, I had designed an isobaric/bandpass box when young once I discovered the physics behind amplifying a particular frequency for a pair of Kicker 12's. The woofers were mounted to a 3/4" plate, one wired reverse polarity, cone to cone. Two chamber box, one side was ported to enhance 60-80hz. Even though there was a 90db loss by being isoberic, the ported design gained close to that back on the ported side at 60-80hz. Sure mid bass sucked, but listening to some "feel the bass" would be a whole different experience to a couple 8" when my trunk lid was jumping 1/2" lol


Boy, those were the days, thanks for the flashback.

[Mwishlist]

Actually firing into the door cards are fine for subs, as long as they don't rattle it will help kill any highs the cross overs don't 100% catch. I think Richard Clark used material or baffles in front if his subs to accomplish this in his legendary Grand National system as a passive solution. It's like having a sub in your trunk, of course you can hear the bass even if it's pumped in behind the seats etc.

Sub waves are large, two subs firing towards each other from a few feet apart are not going to cause any noticeable cancellation. If that were the case, every car in the world that has two 6.5 speakers in the door panels facing each other would cancel all the mids and bass out. If you reverse the phase of one of those subs you would get massive cancellation, but that is regardless of how the subs are facing; its based on the waves being reversed and cancelling out.