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Discussion Starter · #1 · (Edited)
TC-2000 Subwoofer in Progress

I have been working with WinISD, BassBox, and Unibox for the past week or so and would appreciate some input! I know this driver really likes big enclosures, but I need to do something significantly smaller than 360L. More than likely this thing will end up in my 150 sq ft apartment bedroom. There is a slight chance it will wind up in our living room which is a whopping 200 sq ft. Yeah, good thing I'm not claustrophobic. I am considering a sonotube, but I have been leaning more toward a tall box, since it seems it would be more rugged.

Most of my listening will be music, somewhere in the neighborhood of 80-90%, the rest being HT of course. I have been focusing on a ported design, but if closed would be better for my situation, I will definitely go that route.

Priorities:
1. Bass must be smooth and tight. I'd like to get down in the mid-teen range.
2. It needs to be able to hold up on my drive back down to school.
3. Relatively small footprint (Results in a tall enclosure that will likely double as a corner table when not in use.)


Here is what I'm thinking:
220 L Effective Volume 44"x20"x20"
Tuned to 15.5 Hz - 6" Diameter x 33" long with sufficient damping and a possible flare inside

Unibox:



BassBox:





WinISD:






Let me know what you think! Suggestions are much appreciated!
 

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Discussion Starter · #2 ·
Well, I went ahead and cut all my MDF last night. I managed to squeeze it all out of one sheet of MDF. Is it okay to use hardwood ply for bracing, or do I need to go back to lowes and buy some more MDF? Also, will 8d x 1-1/2" wood screws be alright for screwing into the edges of my board, or should I run a little brace along the inside corner of the box?

One final design question, how bad will my standing waves be? The driver will be down-firing, and the parallel face will be 46.5 inches away. Of course I plan to install some closed cell foam on the ends. I was thinking about adding two braces with an inch separation and offset holes to the center of the box. Of course sound waves don't travel in straight lines so it wouldnt be entirely effective, but would this idea be useful in reducing standing waves?

Thanks!
 

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Never use screws with MDF. You are asking for trouble as it will split. Never nail it either. Glue and clamps are more than sufficient for a solid MDF joint. I would prefer that you use MDF for bracing, the plywood would probably be ok but MDF is more dense and gluing like materials is always a bit better. I've been woodworking for more than 20 years and have built dozens of speaker enclosures and subwoofers and swear by MDF. I've never once used a nail or screws in the enclosures. Just good elmers wood glue is enough. When clamping be sure to just snug it up, do not over clamp or you'll starve the joint of glue. Clamping should just be holding two or more pieces together NOT compensating for a poor cut. Take your time and be sure the cuts are square and straight and you'll be golden.

If you have no other alternative...IE can't afford or don't have enough clamps then you may want to try MDF screws. Be sure to pre-drill the ENTIRE depth of the screw or even those will split. Personally I stay far far away from mechanical fasteners with MDF.

You can visit my site to see what my bracing and enclosures look like. Visit the home theater section and look at the Tempest project, the Kit281, and the AV2.
 

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I did screw and glue my whole box together (not enough clamps, nor experience to just glue it).

make sure to predrill, or i guarantee it will split. also use a larger bit to provide countersink for the screw.

I ended up placing a 2x2 frame along the whole thing so that i was not screwing the MDF to MDF, it was MDF to the 2x2 frame. that way i could screw further into the MDF and into a stronger larger support.
 

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Discussion Starter · #6 ·
Thanks for the responses guys! Darren, that is some amazing work you've done! (That shelby you have your eye on is definitely a winner. I can't wait to see that!) Unfortunately I only have 3 pipe clamps to work with. I think I can manage with those as long as I have a nice straight 2x4 between the clamps and the mdf. If that fails, I'll move to screws! But hopefully it will work and I can return my countersink/pilot hole bits and screws. I'll try to make some progress today! Thanks again!
 

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Your standing wave problem will be shifted to a more manageable level if you have the driver 45% of the way up the front rather than at the bottom of a tall cabinet.

Grab yourself a copy of boxnotes to experiment with this phenomenon.

Standing waves can add a peak in response, which can be up to 6dB if it coincides with more than one resonance.

Closed cell foam on the offending surfaces can really help. (top and bottom)

Your idea of offset braces is unlikely to help with the low frequencies you are trying to minimise, and has the potential to cause whistling and turbulence inside the box.

Three pipe clamps will let you do a fair bit of constructing. You can also use rope tied around the box and twisted tight with a stick to get additional clamping
 

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Discussion Starter · #8 ·
Thanks for your help, Collo! I really appreciate it! In fact, it was your program that made me aware of the problem in the first place. I modeled the finished product in sketchup, and I think I prefer the looks of the front firing configuration! I'm sure it will sound better too!
 

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Discussion Starter · #10 ·
You'd better expect photos! I bought a new camera a couple months ago and haven't had a chance to use it.

I do wonder about one other issue, will having the 6x34 inch port vertically oriented be an issue? The driver has a mounting depth of approximately 8 3/4 inches, taking into account driver venting. With that in mind, the port will have to be offset from the centerline. This will give me about 3 inches between the outside of the port and the inside of the back wall. Will this cause my actual performance to diverge significantly from simulations? :dumbcrazy:
 

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Vertical port is fine, just make sure the cat can't fall in!

Moving the port closer to the back wall may change the tuning slightly, but I wouldn't worry about it. You will still have plenty of clearance between the the port intake and the other walls.
 

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Discussion Starter · #12 ·
You tha man, Collo! Thank you so much for your help! Ping pong balls are my biggest concern. I'm definitely going to have to put a grille on that thing. :)
 

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Discussion Starter · #13 ·
Thought I'd go ahead and post a pic. It's just a quick shot of the driver. This is one of the tall surround tc2ks. I'm excited. I am hoping to have a few braces cut tomorrow. We are in the middle of a move, so this may turn out to be the longest build in history. :)



 

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Discussion Starter · #15 ·
I have bad news... The movers destroyed my work thus far. With all the craziness going on right now, and half of my tools lost in boxes or back in Memphis, I'm going to go ahead and salvage what wood I can, and build a smaller sealed box. Some of you are probably groaning as you read this, I am too. One day, this driver will be in the beautiful box you see above, but not just yet. On the bright side, at least I will be able to fit it in my car for the 7.5 hour drive back to school. And in case you were wondering, I plan to file a claim with the movers for the cost of the mdf.
 

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Discussion Starter · #16 ·
Well I've routed the holes for the driver. I didn't feel like practicing, so I took my homemade plywood jig and made my cuts in a basement closet. Not the best idea... There is dust everywhere. But the circles came out great. TC Sounds suggested cutout diameter seems a little large. I measured the mounting ring diameter, and that one fits like a glove. I may have to sand it down a little more, since I expect the gasket to expand as the driver is bolted in.

What is the best way to mount the driver in mdf? I have the screws that came with the driver. Would mounting another 1.5" wide ring of mdf be substantial? Or should I cut some hardwood blocks and mount them for the screws?

Here are a few pics of my holes. :)



 

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well what i did was to double the MDF on the entire front and then to use T-nuts to secure the sub. The T-nuts are allot more removal friendly compared to screwing it in every time to the wood.

If you could do 2" wide, then glue the **** outta it i think you would be fine.
 

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Discussion Starter · #18 ·
Thanks for the reply ccdoggy. Will I also have to purchase new mounting screws? The driver came with some hex head wood screws, I wouldn't think that they would work with the t-nuts. Maybe a visit to the hardware store will clear some of this up for me.
 

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Discussion Starter · #20 ·
Yup! It was definitely disappointing. Luckily, I was able to use a good bit of what was left. I need to find some sandpaper and clean up my cuts. I think I'll try to laminate the two front panels together tomorrow. This little box has been neglected long enough! I neeeeed to hear this thing!

Another question for someone: I noticed that the surround on my driver overlaps the mounting holes. What is the best way to deal with that? Should I xacto out the holes, or should I just ignore the overlap? And what is the best place to find closed cell foam locally? I checked the Home Depot up here in KY, but didn't have much luck.
 
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