The piece will be sized to have a 1/4″ overhang on the sides and rear, and the front will have up to 1.25″ overhang (which is how far out the woofer’s surround protrudes from the box). With the flexibility of waterjet, I couldn’t stand to leave it all straight, so I added a little contour on the front.

These will be cut at my local friendly waterjet shop. Each will weight about 55 lbs. Here are some requisite renders. The edges will be polished and there will be small chamfers in the top and bottom to minimize face/head damage of small children.

UPDATE 01/23/2013

Granite has been cut. Will have the edges profiled sometime in the next week.

The stone is called Labrador Green. This is very similar to, if not the same as, Uba Tuba.

Update 02/11/2013

Edge profiling of the granite sub tops are complete.

granite subwoofer top

This is the final arrangement of the speakers and subs. I had originally placed the subs on the inside of the speakers, to broaden the soundstage, but there was a resulting nul between 60 and 90 hz impacting the mains. Rearranging them took care of it. My next post will cover this in greater detail.

With a 3.67 year old, the only time my house is reliably quite is at night. Last night was my third is the last week of evening spent making pink noise and sine wave sweeps. My wife is sweet to tolerate it.

The first few times I will write off as experience. I had some troubles with my UCA-202 producing phantom signals sub 20 hz, so I’m using my M-Audio firewire solo, a Dayton EMM-6 (calibrated by CSL), and a Radio Shack SPL meter. The purpose of the measurements are to help create EQ filters for use with a balanced Mini-DSP 2×4.

NOTES: Unless indicated on the image, the graphs have no smoothing. All measurements were taken with a 60 hz crossover between the sub and main speakers, controlled by the receiver.

These are close-mic measurements taken 1 foot in front of the sub.

This is before any EQ, taken from the main listening position. Graph shows subwoofer alone, mains alone, and both together.

Here are the filters I used.

This is before and after EQ (of the subwoofer alone). I didn’t use very much EQ. A minor Linkwitz Transform to extend the -3dB point from 38 hz to 33 hz, and some filters to lessen the hump from 30 to 60 hz.
Because I have so much power on tap, I did not want to apply much boost to the low end. I plan on building a second one of these, and at that point I might try to find the very limit. For the time being, I am happy to preserve the natural roll-off of the sealed box. At least until Audyssey gets ahold of it (See below).

After the EQ I raised my sub trim slightly. The result is the pink line above. Not bad, but I have a hump outside the passband of the sub that I can’t touch with the Mini DSP. The blue line is after running Audyssey. It tames the 100-250hz hump.

So, nice and flat, right? I have some concerns about the boost in the sub 25hz area. There is a 10 db rise from 25 to 5hz. I don’t know if a little boost can create even more room gain – so I’m unequipped to reverse engineer this, but nonetheless, I am inclined to undo it for now.

This is a zoom in of the sub-40 hz region. Blue line on top is AFTER Audyssey. Pink Line is BEFORE Audyssey. And the green line is what I have AFTER disabling my little LT in the MiniDSP. I will probably be back to the drawing board with this. Though I may just leave it for now and reapproach after adding the second sub. It’s nice and flat, and as long as I don’t crank it up for the heaviest move scenes, I’ll be okay.

Here is the current home for the sub. I moved things around a bit. Moving the sub to the inside of the speaker gave help with a null I was having before. I’ve got room for another one on the opposite side when I have it built.

12/19 – Attaching the dowels to the baffle

I started by placing the baffle on the box – face up. Added the PL to the dowel, carefully avoiding the hole. Then lifted the baffle to put the dowel in place. I kept the baffle raised slightly until I got the bolt started, then used the power drill to get it close, holding the dowel in its proper orientation (I had marked the side I had determined best to be facing the cut out, and each dowel and hole were numbered). I got them plenty snug to stay put, but avoided burying the bolt head into the baffle.

I should note that I made the holes in the dowels somewhere between 1.125-1.25″ deep. The inserts are 0.78″ long. This gave me some room behind the insert to snug the 1.75″ bolts without messing with washers or finding shorter bolts. I figured it would also be good should I need/want to add a second baffle, and can’t find bolts exactly the right size to be tight right at the end.

Once they were all in place, I clamped the baffle to the cabinet roughly between each of the dowels. Checked to be sure they were all plenty tight against the other end, then removed the bolts.

The bolts had anywhere from 1-5 threads coated in the PL. Any more than a few threads could only have gotten “wet” upon removal. Then I took some varied-length clean 1/4-20 carriage bolts and threaded them in the holes to keep out any expanding PL. I unthreaded them a 1/2 turn or so every 45 minutes for a couple hours.

The minimal squeeze out toward the cutout was easily wiped away.

After clamping the baffle to the cabinet, this was the condition of the bolts.

Temporary bolts used to keep the PL out of the inserts.

All in place.

UPDATE 12/20

This morning I removed the carriage bolts – they all came out easily and clean. If there are any PL artifacts in the inserts, it won’t impede function. I kept the clamps on until late afternoon.

As much as I trust the PL, I was very cautious carrying this around.

Baffle side of the dowel.

As it sits now. Final gluing of the baffle to the box and the 8 dowels to the rear wall.

UPDATE 12/21 – COMPLETED (but not finished)

Assembly complete.

Lined the walls with a healthy amount of polyfill.

Gasket tape.

I was going to first install it with the rubber gasket that came with the driver, but I was too eager to drill the holes larger to fit my bolts.

Driver installed.

Problem #1. The PAPER THIN veneer on the plywood shaved off when I was flush mounting. The wort of this was at the back of one of the sides. I was leaning toward paint anyway, as my tests with wood finish on this veneer were not satisfactory. So in the end, this is a non-issue, thankfully. My initial test of flush trimming didn’t reveal this problem because it was where the side met the top – and the top and bottom were made from a different plywood with a thicker veneer. Live and learn.

Problem #2. The outer layer of the ply chipped in the upper right corner of the baffle.

Story continues with EQ’ing HERE.

Final non-baffle dowel installed. The driver cutout for the baffle is complete. The next step is to work on the dowels that will tie the driver to the cabinet – I need to make a jig to drill straight 3/8″ holes in the dowels to receive the threaded inserts.

Circle jig.

First pass.

Driver hole complete.

I used a brand new down-spiral bit. It was very nice to the veneer.

A small preview of the final box.

This was the last non-baffle dowel. A little wedge is clamping the wood into position.

This is the bolt and threaded insert that will attach the driver to the baffle by way of the dowels that stretch from the baffle to the rear.

— UPDATE 12/19—

There was a little bit of rub on the baffle from the inside edge of the mounting flange. It made it just a little tough to turn as I was positioning the driver for marking the mounting holes.

A tiny little roundover solved that.

Testing the fit, just before drilling the holes.

Ditto.

I wasn’t sure how I was going to do this – I had envisioned making some sort of captive sled for my drill which held the bit perfectly level, and a jig to hold the dowels, and a stop to set the depth… But then I remembered I had just bought a doweling jig recently and it would do just fine for this. First test with it was a keeper.

First one done, installed nice and straight.

The insert was installed just under flush.

This is why the inserts are offset from the center of the dowels. Positioning it off to one side was the only way to avoid encroaching on the driver hole. The added benefit is that I can swivel it a little bit if a mounting dowel is too close to one of the internal dowels. Of course I had drawn it all perfectly, but I’m sure some of my dowels are not perfectly on the mark.

These are the feet I am using. They are Penn Elcom 9106 – 1″x2.5″ – massive feet. They feel like they could hold my house. They attach with 1/4-20 bolts to knock-in threaded inserts.

12/19 PM

The rest of the dowels have been drilled and the inserts are installed. Two of the dowels may need to be sanded down a little bit at the top, as my un-centered hole may not have been un-centered enough. Should be easy though.

8 dowels complete.

This was the real hero of the task. This is a Bondhus t-handle hex wrench. I had the foresight to avoid the common slot-driven threaded inserts. With the very coarse threads on the inserts, having proper leverage is key to installing them straight. Using the hex-driven inserts that I have with a commonplace L-shaped hex wrench would not be much easier. The t-handle wrench allowed for full exertion of force while threading.

Not glued in yet – that is the next challenge.

 This project is continued HERE.

Cabinet will be constructed from a single layer of pre-veneered plywood from Menards. I had some left over from another project. All bracing will be from 1.25″ solid wood dowels. The net internal volume is calculates to 4.24 cubic feet. That includes .2 cubes as indicated by SI for the driver’s displacement. If there is any imprecision in that number, it is from the driver. But certainly this is close enough.

8 dowels will span from the front to the back, lining up with the driver’s 8 mounting holes. With a single baffle, I felt it was important to brace the front as much as possible, and to couple the driver to the cabinet as much as possible. In total, the dowels remove 0.2674 cubic feet volume from the enclosure.

This is going to be the means of attaching the driver. Eight dowels will line up with the mounting holes, and each will have a threaded insert in which the mounting bolts will attach. The dowels will reach to the rear of the cabinet.

 UPDATE 12/12

I had a material mismanagement issue halfway through the table saw work. I had to buy an extra 4×4 of a similar yet not congruent oak-veneered ply. The new ply is not quite as nice, but will suffice nonetheless. Top and bottom will be from one type, sides/front/back from the other.

UPDATE 12/14

Wood has been cut, and I’m 66% finished with the double rabbets. Should be able to finish them off tonight and start gluing it together.

UPDATE 12/14 (evening)

Dry fitting. Looks good.

First glue. Attaching top and bottom to one of the sides.

UPDATE 12/15

Gluing other side to bottom and top.

Double rabbets.

Dowel bracing. There will be more of this.

UPDATE 12/16

Preparing to attach the rear.

Rear in place.

I was glad to see that the excess glue (PL Premium) will come off nicely when I flush everything up. The dimensions of the cuts and rabbets were such that I’d have an 1/8th to trim from all overhangs.

This project is continued HERE.

.

.

The next and final step for this will be to add mahogany sides.

Here is a before and after. I failed to get many shots of the black casing before sending it off for coating.

I suspect the word “request” is an understatement.
————————————————–

This version is designed for the OPPO BDP-93 and BDP-95 Blu-ray Disc players. Comparing to the previous official release version BDP9x-61-1219, the major changes included in this version are:

1. Resolved the loading failure issue observed on several recently-released Blu-ray movies, mainly Universal Europe (EU) releases. Their US releases have no known issue. Sample titles include “Jurassic Park Trilogy (BD Box Set, 2011)”, “Kong Fu Panda 2 (BD, 2011)”, “Fast Five (BD, 2011)”, and “National Lampoon’s Animal House (BD, 1978 version)” etc. With the previous firmware, disc playback will automatically stop once you go to the Main Menu and select to PLAY. This firmware properly loads and plays all the above Blu-ray titles.
2. Improved general disc compatibility based on recent and upcoming Blu-ray releases as well as user-submitted disc samples including “Mr. Poppers Penguins (BD, 2012)”, “Dragons Gift of the Night Fury (BD, 2012)”, “Human Planet (BD, BBC Documentary)” and “Nine Inch Nails, Live – Beside You In Time (BD)”.
3. Per the request from the studios, the ISO file playback function has been removed in this firmware version. The previous firmware had the ability to play ISO files, but it was an undocumented function and was never officially announced or supported. Future firmware version will no longer support ISO playback.