12W6v3-D4 Early Summer Project

[KirK]

Hi Gang!

I thought I would liven this place up by informing everyone about my plans for undertaking another subwoofer enclosure project.

You can expect some images to be uploaded by late May to early June. I will work my best to document images of the project throughout its course.

I will also provide some pedagogical remarks (helpful tips) to the prospective DIYer who is anxious to embark on loud speaker cabinet design.

My kind regards,

KirK

[KirK]

Hey guys (in a generic sense!),

Here is the first of several images, I think I have uploaded it. The image is not Photo Shopped, that is actually two 12W6v3-D4 subwoofers. The one on the left was purchased from Creative Car Audio in mid March and the one on the right was bought at Earmark back in early February.

Because Earmark still has not attained the Authorized status I am inclined to keep the one I bought from Creative Car Audio and sell the other. It would be interesting if I could keep both, however, 100 A would just be a nightmare on my 120 A Valeo Alternator.

I'll put the one I bought from Earmark on eBay sometime between June 15 to June 20. I'll offer a 15 day Money-back-guarantee should the unit be DOA. Also, I am not interested in pursuing any other unsecure forms of transactions, so if you're interested just look for it on eBay. It is new, it just has been in my dorm this last spring semester collecting dust. The unit was not subject to power and was not installed. Us Civils are just constantly working on assignments and laboratory reports during a semester, so the unit was simply collecting dust, but in its shipping carton most of the time.

My only qualms with the W6v3 is its absence of a shorting ring. TC Sounds use shorting rings so consequently their drivers attribute high motor force BL factors. However, I find the W6v3's more aesthetically appealing than TC's drivers. What's more, it was astonishing that the 12W6v2-D4 had a BL > 20 Tesla meters back in '03, this was accomplished without a shorting ring. I am certainly not expecting higher motor force BL factors for the W6v3's; the NBR surround was a major selling point for me.



Sorry for no image yet, let me see what I can do.. (OK, disregard, got it...) That was just my damn Canon messing things up before... Let me know if you guys have any problems viewing at your end.

Enjoy!

KirK

[KirK]

Hey guys,

FYI, I am spending two weeks with my aunt and uncle. I'll upload some images of the enclosure and accompany it with some text in mid June. I just didn't want you guys to think I am MIA.

KirK

[KirK]

My bad, guys, I said between 15 - 20, but its 06/21... The 12W6v3-D4 is now up on eBay for auction for those interested.

I am still getting acclimated to PST, I crossed over two time zones when I was visiting.

I will begin generating some new images and accompanying text in the next several days. Sorry...

[KirK]

Sorry guys,

It has been unusually warm out, but here are some images of the enclosure project's progress.


The images show the dados and the side panels. The early stages of the project. Looks like the early summer project is becoming a mid summer project.

[KirK]

Hey guys, here are more images.


The first image gives a rough idea what the enclosure is going to look like. The second image shows a dado that accommodates an angled wall in the inner port wall. The third image shows another dado that will accommodate the same angled wall but in the left panel of the enclosure.

Now I know what you're thinking. A wedge enclosure inside a traditional rectangular prism enclosure is impractical for spatial reasons. While there's no disputing that, when I think of subwoofer enclosures I typically envision the Home Theater enclosures, which are almost always rectangular prisms. So I guess for me this constitutes the best of both worlds; the sound quality of a wedge and the traditional appearance of a subwoofer enclosure. Space usually isn't an issue for me, I have a cavernous trunk, and I am asocial so getting a family vehicle won't be an issue for me anytime soon, LOL. Stated simply, a spatial aspect is not of that much concern to me.

Here is the key to a wedge's sound quality:

In a traditional enclosure comprised of vertical walls, as the sound wave propagates from the rear of the cone to a back wall or port wall (vertical presumably), the wave contacts the wall forcing the wave to propagate back into the rear of the woofer causing superfluous oscillations that discernibly mar the sound quality of the enclosed system. This is known as a loaded or standing wave.

In a wedge, the sound wave propagates from the rear of the cone to an angled back wall or port wall, the wave contacts the wall and becomes deflected forcing the wave to propagate into the bottom of the enclosure, and thus not making subsequent 'direct' contact to the back of the woofer. All of this translates into the woofer oscillating only to the prescribed frequencies from the electrical signal and hence the intended sound quality. The key is the deflection of the sound wave. For best results, angle walls or port walls between 30 and 60 degrees.

[KirK]

Hey everyone,

Here is the image of the angled wall fitted into its dados. What a tight fit, my drafting really paid off!

Tomorrow, my father and I will be cutting the mounting hole in a 0.75 inch baffle and an outer hole in a 0.5 inch thick piece of MDF. The two together will form a depression in the front baffle the subwoofer will sit in. This has been popular for awhile now so it's definitely nothing new. The visible depression ring will be painted silver and coated with epoxy to accent the subwoofers cosmetics.

[KirK]

Hi everyone,

Here are some more images.

Unfortunately, today was a scorcher so we'll do the mounting holes tomorrow. The first image gives another idea of the overall shape of the enclosure as well as what's going on with the port. The second image shows the 280 mm diameter circle for the mounting hole in the front baffle along with my 8 year old compass. That compass is older than my nephew, LOL! The third image shows the dado in the front baffle that will accommodate a double layer left panel. The fourth image shows the inner back wall with its dados to accommodate the left panels, the inner port wall, and the right panel.

Tomorrow, a new grille will arrive for the 12W6v3-D4. This will come in handy to minimize any direct contact of the NBR surround so as to prevent any mishap in handling the woofer for any fine sanding in the likely event the mounting hole isn't quite right in some places. Tomorrow we'll tackle these mounting holes.

[KirK]

Hi everyone, here are more images.

The first image shows the actual cutting process of the mounting hole in the interior baffle. The second image shows the finished mounting hole in the baffle. The third image shows the 0.5 inch thick exterior front baffle that will form a depression. The fourth image shows a Birds Eye View of the grille resting on the transducer. The fifth image shows an angular view of the grille resting on the subwoofer. The sixth image shows a plexiglass viewing window made to order from Interstate Plastics.

The cutting process of the mounting hole is really where my father shines in his carpentry skills. Unfortunately, he always invariably uses his saber saw making the process more challenging than it has to be. I occasionally inform him that there are saws that can make such circular cuts at Lowes and HD, but his response usually entails that such a saw would require a modest horse power motor needed to supply the torque. Uggh! I don't know ... I am studying CE, not physics, so torque is seldom ever encountered in an engineering curriculum. We work with 'Moments', which is almost similar...

We didn't get to the other hole for the exterior baffle layer. It was too hot; the temperature at noon was 109 'F' degrees! And when I am using F I am not referring to Fahrenheit, its more like '@#$%ing', LOL!

Other images include a Birds Eye view of the grille that has arrived along with an angular view of the grille. About a week and a half ago, I ordered a 11 inch by 6 inch by 0.75 inch plexiglass that will act as a viewing window on the left side of the enclosure. The plexiglass will sit atop a 9 inch by 4 inch hole in the MDF in the left panel; that's why we used a double layer on the left side. I needed to think of some way to still admire the motor and satin black basket once the transducer was installed.

[KirK]

Here's the plexiglass window.

[KirK]

Hey everyone, I had trouble accessing carREVIEW yesterday, but here are more images.

The first image shows the 13 inch diameter cut out on the exterior layer of the front baffle. The second image shows the 0.5 inch deep depression that the subwoofer will sit in. The third image shows a cut made in the bottom of the enclosure that will accommodate the outer layer of the front baffle. The fourth image shows the same thing but the only difference is that it's the top of the enclosure. The fifth image shows some 12 AWG speaker wire that was bought from Crutchfield.

I did some number crunching the day before yesterday to calculate the actual net internal volume of the enclosure. It turns out, after the subwoofer displacement the volume is about 1.36 cu. ft. So, I would imagine with the caulk, speaker wire, and accent lighting that will go inside the enclosure will take us under 1.35 cu. ft. The nice thing about that is if we take it to two significant figures, we round down to 1.3 cu. ft.

I also was able to calculate depth clearances using some traditional right triangle trigonometry. The pole vent clearance is about 4 inches making for a 'happy voice coil' to quote Steve Turrisi. This clearance will work wonderfully with the PVAC. Our angled wall is angled at about 56 degrees using the same underlying trigonometry.

[KirK]

Hi everyone, here are more images.

Today we worked on dry fitting the enclosure, the 0.5 inch thick exterior layer of the back wall, and filleted some of the corners on the port walls. The first image shows us dry fitting the entire enclosure for the first time. The second image shows a very refined idea of what the overall enclosure is going to look like. The third image shows the external layer of the back wall; the back wall is comprised of two layers, a 0.75 inch thick internal layer and a 0.5 inch thick external layer. This will come in handy later when we make an access gate in the back to replace a small light bulb when needed. The light (LED, incandescent, halogen, xenon... we're not sure yet) will accentuate the main chamber, the frame, and motor structure of the subwoofer visible through the viewing window. The fourth image shows a filleted corner of the inner port wall. The fifth image shows a filleted corner of the intermediate port wall.

Rounding or filleting any sharp corners in the port area that high velocity air passes over is critical for the sound quality of a ported enclosure. JL Audio makes a pretty spot on analogy: "The mechanism that gives a whistle its characteristic sound is high velocity air passing over a sharp corner. A sharp corner in a port attributes a similar effect." The thing that plagues ported enclosures with ports without filleted corners is a low pitch whistling sound. This is actually caused from turbulence of the propagating air at the unrounded corners. Conversely, a rounded corner subjected to high velocity air will promote a laminar (smooth) passage of air exiting the port.

[KirK]

Hi everyone,

Today we just worked on filler pieces for superfluous dados. The reason being is when we dado the top and bottom we have to take the dado all the way across; we're not working with any extravagant carpentry equipment by any means. So tomorrow I'll upload some images of the top and bottom after the excess in the filler pieces has been sanded off.

Tomorrow we'll also be browsing around automotive places that sell the accessory accent lighting we're looking for. By evening, I would like to make the 6 inch by 11 inch hole that will accommodate the plexiglass as well as the 4 inch by 9 inch hole that will subsequently be behind it. In the mean time, you can enjoy the images in the preceding posts.

[KirK]

Hey everyone, I just thought I would clarify something I stated in an earlier post.

BL factor is a measure of how refined a subwoofer's motor system (magnet(s) and voice coil former) is in controlling the excursion of the woofer ( diaphragm, cone, driver, etc. ).

JL Audio does not necessarily take home the grand prize here. TC Sounds really backs up the motor of their transducers with not only Finite Element Analysis, but also with shorting rings making for a extraordinarily high BL factor (23 - 27 T * m). BL is measured in Tesla meters in partial homage of the Father of Alternating Current, Nicola Tesla ... my Avatar on carREVIEW, and a truly profound intellect of his time. The higher the BL the more linear the subwoofer is in reproducing the intended passband.

Motor and suspension systems subjected to the scrutiny of FEA usually translates to a better than average BL factor. Resonant Engineering Audio, TC Sounds, the earlier Adire Audio, and JL Audio constitute just a few of the major players for applying FEA in automotive transducer manufacturing. Daniel Wiggins has phenomenal patents for his transducers such as XBL^2.

Finite Element Analysis is a big deal in all branches of engineering. Fundamentally, its those optimization problems studied in Calculus 1 and 3. However, that's just the tip of the iceberg. Optimization is fully investigated in a course on Applied Partial Differential Equations. I have only taken Differential Equations since it is the highest math I needed for Civil Engineering, but I would imagine EEs would have to take Partial Diff EQ or something similar to it.

Anyway, just thought I would clarify...

[KirK]

Hi everyone, here are more images.

The first image shows a bolt hole circle traced with a compass along with a centerline. The second image shows the trim ring being used as a mounting template. The third image shows the bolt holes drawn after completion. The fourth image shows the bolt holes drilled in the front baffle.

Using a T-square, bolt hole circle facilitated by a compass, and a mounting template to get a subwoofer centered in the front baffle is a technique that has been around since early enclosure building back in the mid 20th century. First, you find the intended center point of the bolt hole circle by measuring the height and width of the front baffle. Second, you use a T-square to find the intersection point of the two centerlines; it usually helps to make a cross to locate the center. Third, take a compass and adjust it to the radius of the bolt hole circle and trace out the circle. Fourth, take a mounting template or trim ring and use two bolt holes opposite to one another to establish the bolt hole circle drilling scheme. It is critical to fasten the template down with tape or some other weak adhesive to prevent any unwanted translation. Fifth, start filling in the other bolt hole circles while maintaining an approximately uniform width from the mounting hole to the inner circle of the mounting template. Sixth, remove the tape and intuitively inspect the bolt hole circle scheme for uniformity. Seventh, use a drill press to establish the bolt holes in the scheme. I personally prefer a drill press since the bolt holes will be perpendicular to the mounting plane. Using a hand drill usually makes for skewed bolt holes.

So again, not necessarily a new idea but I thought I would take the time to explain that to any DIYers.

[KirK]

Just a few more images for tonight here.

The first image shows the filler pieces in the superfluous dados on the top of the enclosure. The second image shows the same but the bottom instead. The third image shows the 9 inch by 4 inch hole that will be behind the plexiglass viewing window. We'll get to the other one that accommodates the actual plexiglass tomorrow. The fourth image shows accent automotive lighting hardware purchased from Pepboys as well as wire purchased from Lowes nearby.

We haven't decided yet what we'll tackle tomorrow, but I'll keep you guys posted.

[KirK]

Hey everyone, here are five more images.

Did anybody here know that I have a fourth woofer? We had this woofer in our family for 13 years as of June 2013. The woofer is a Spaniel, Cocker Series, LOL! Just like the others, this woofer can get modestly loud, especially when we're eating lunch and dinner. I measured the brief outbursts to be an eardrum jarring 81 dB C Weighted, LMAO! For namesake, we call the little guy Buddy.

Joking aside, we worked on filing down the 9 inch by 4 inch hole in one of the two left panels. The 6 inch by 11 inch hole in the other was completed and filed down as well. One image shows the plexiglass fitted into the 6 by 11 hole and another shows somewhat of an idea what the two will look like.

Tomorrow, we'll work on the access gate in the furthest back wall of the enclosure. We'll also possibly browse HD for some rubber gaskets that will seal the perimeter of the access to the light within our angled wall.

[KirK]

Hi everyone,

Today we worked on the light access and fixture for the accent lighting that will go into the enclosure. Beforehand, we went into town looking for a rubber gasket which we eventually found at HD. This will be used to seal the access to our accent light. We hoped to find some black silicone for the caulking inside the enclosure since we'll be painting the inside black. However, we struck out at both HD and Wal-Mart. Although, we found some amazing spray paint for coloring the depression. We typically have always used Rust-oleum to paint the ports. We found American Accents bright metallic Silver, which IMO best fits the application for the depression, and believe it or not, we bought it at Wal-Mart. Albeit we bought some good spray paint, I would still like to use polyurethane as an overcoat. The nature of MDF is such that the surface texture is not necessarily completely consistent. To compensate for any non-uniform gradient, we'll still use a clear coat.

I have always been proud of my father's competence in wiring circuits. He rose through the ranks at Atlantic City Electric starting out as a Helper and retiring as a Commercial Energy Service Representative much to the contempt of his Blue Collar coworkers and In-laws. There were instances when I first got into car audio in mid adolescence that I contemplated pursuing EE after high school. However, he was quick to dissuade me from pursuing EE stating that most of the EEs' he worked with had egos inversely proportional to their height.

I think I found my calling with CE. We see these catastrophic failures of our infrastructure more and more frequently; the wretched work of Bean Counters (the politicians and economists that constrain such necessary engineering ventures). This country is in dire need of an infrastructure overhaul, and I sincerely hope that I can make a difference sometime in my life.

[KirK]

Hi everyone, sorry for not posting yesterday, I got distracted by Whose Line is it Anyway?.

Yesterday we worked on a couple things. We completed the lighting circuit as shown in one of the images and made sure it's operative. We'll run the positive inline with the 4 AWG positive going to the amplifier. I don't know much about circuits yet, but I know, intuitively, it would be a bad idea to run the positive inline with one of the positives on the subwoofer channel, LOL!

We worked on dry fitting the enclosure. There were a couple minor issues in some places, but they were resolved. We applied a second coat of silver spray paint to the depression. One image shows an almost complete idea of what the enclosure will look like, while another shows a back view of our port.

[KirK]

Hi gang,

We didn't do that much today. We made an access for a toggle switch for the lighting circuit. In one of the images you can see it in the left panel. We went into town and bought the elusive black silicone from Ace. A very kind employee there directed us right to the caulking. We also bought black spray paint and some new wood filler. The black spray paint will be applied to the port and the interior of the enclosure.

We also discovered that our angled wall is not completely even in its dado, so we'll have to cautiously sand it down on one side. Our estimated time of completion of the project is 07/25/13, next Thursday. We also discovered we don't have enough carpet, so I bought some charcoal grey at Crutchfield. This purchase is estimated to arrive next Wednesday, 07/24/13, which is perfect for our timeline.

[KirK]

Hi everyone,

I felt it necessary to complete the holes for the back access of the enclosure. I designed it big enough so I can fit a Phillips head in there with no problem. Tomorrow, we'll cut a 12 inch by 14 inch gate that will act as an access panel for changing the lighting inside the enclosure. I think that will be better than having to remove the subwoofer each time the bulb needs replacement, and, besides that light will only be on whenever I have the urge to admire the inside of the enclosure.

The back walls have been glued together so when we dry fit the enclosure tomorrow, we'll know definitively if the slanted wall is the issue for the top and back walls not fitting together tightly. After that, it's really only a matter of fine sanding, applying wood filler and filler pieces in some places to make the enclosure look consistent overall. Another coat of silver spray paint was applied to the depression making for three coats thus far. Pretty soon we'll be ready to assemble and glue the enclosure together with ... what else?
...
Gorilla Glue.

[KirK]

Hey guys,

We finished the back access today as well as installed a screw-in terminal cup in the access panel. We took about a sixteenth of an inch off of the angled wall, so now everything fits very well. The next couple of days will consist primarily of spray painting the inside of the enclosure black as well as continuing to paint the depression silver. We'll apply wood filler in some places as well as wood to make all the plane surfaces consistent. Then, we'll glue the enclosure up and once it's cured we'll apply some black silicone caulking on the inside. So, perhaps the next couple of days, images may be sparse. Sorry.

[KirK]

Hey guys,

It was raining off and on today so we just started painting the inside panels and port walls with black lacquer. Looks like there may be an onslaught of showers the next 2 to 3 days. Uggh! I swear, sometimes I think the small desert town my father lives in is the epitome` of inconvenience! We'll try getting done whatever we can in the next couple of days...

I also would like to clarify something a vast majority of consumer electronics reviewers seem to advocate these days concerning 'Break-in Periods'. I spoke with Mike West at JL Audio and he even stated there is NO Break-in Period for the W6v3's. So as long as the transducer is not subjected to clipped output from the amplifier, the subwoofer should be fine. I wonder if sometimes these consumer electronics reviewers deliberately fabricate this 'knowledge' to perpetuate their ignorance to others that have the misfortune of reading their biased review. I have long retired from composing reviews as it seems like the only reviews that have 'credibility' these days are of the subjective and biased type.

[KirK]

Hi everyone,

Today we glued the enclosure and allowed plenty of time for the Gorilla Glue to set as we started the gluing at 10AM. We applied some filler pieces that will subsequently be sanded to even out the planar surfaces. As you can see, the Gorilla Glue has expanded in some places. That's just the nature of the beast. My line of reasoning is too much glue is much better than not enough. There's an image that gives an idea of what can be seen through the viewing window.

A special guest paid us a visit the day before yesterday; you may know the guest from Harry Belafonte's Banana Boat Song. Anyway, s(he) inspected our progress and requested that we play the Banana Boat Song, ... LMAO! Fortunately, the rain has cleared up so we didn't have to work all night on a drink of Rum, LOL!

Tomorrow, we'll do some sanding and if time allows, we'll carpet the enclosure. We'll also possibly complete the drilling scheme for our plexiglass window; time permitting.

[KirK]

Hi everyone,

We sanded down the corners today and applied silicone on the inside of the enclosure. The charcoal grey carpet arrived today. Tomorrow we'll apply one more layer of silver spray paint to the depression and we will carpet up the enclosure. We'll establish the drilling scheme for our plexiglass window and will install the 0.75 inch window.

We'll be celebrating by hiking at a scenic state park. We'll have to reclaim those precious calories and reward ourselves with Fuddruckers afterwards.

When we come back, I'll install the 12W6v3-D4 in the enclosure. Don't worry, I'll upload plenty of images.

Take care guys.