My 15" TC2000 LLT End Table Project

**tundraSQ** · **03-02-08, 10:35 AM**

I thought I would start a thread and keep all my thoughts and problems focused in one place. I have been all over the place with stupid questions and interrupting other peoples threads in trying to find answers to building a sub. Now I have my own page and I will post useless information during the build here, instead of getting in other peoples way.

The Driver: TC Sounds TC-2000 4ohm SVC 15" subwoofer
The current amp: ButtKicker BKA1000
Box design : 12 cut ft (net) LLT
Port: undecided.... either 3 4" 36" long ports or a single 6" 24" port.
room: 12' deep by 23' wide and 8'ft high

I want to thank everyone who has helped me in finalizing the design and pushed me to try to build an LLT subwoofer. I have built a million sealed subs and this will be my first ported design, and hopefully it will serve me for awhile. I have shown the following picture to my wife and she has signed off. So I will begin gather wood and parts today.

The plan is to build the box from a combination of 13ply BB and 3/4" MDF. I will trim it out in maple I think, and the top may be granite or corian as I have a piece of each I could use.

Now on to the questions:

1. I was hoping to avoid a down firing sub, but it would be easier to downfire this and hide everything underneath. I have read that TC sounds recommends against down firing, and I would like this sub to last. Is it OK to downfire a TC2000 15" driver?
2. Porting question....I have a ton of 4" PVC and if this isa better choice I will use it....but it would be MUCH simpler to do a 6" downfiring port assuming I know the recommended clearance of the port inside the box. I can also port to the side that will be hidden....just looking for advice here.

Thanks for looking, and thanks for any input.

**tundraSQ** · **03-03-08, 06:55 PM**

I am getting ready to order parts and I am going to order some damping foam for the walls. Is there a preferred material for a LLT box? I see both fiberglass and acoustic foam being used in sonosubs. I have always had a thing against using fiberglass batting as it would seem to be possible that the glass fibers could damage the woofer/ or blow out into the room.

My other question is how much fiberfill do people use to stuff the box? I'm guessing a very loose stuff? 1/3 of a pound per cuft?

**Warmon** · **03-03-08, 10:00 PM**

Most people are using the "egg crate" mattress foam from Wal-Mart. I agree with you, I wouldn't use fiberglass either. The pic in your first post - is this your inspiration?

**mrstampe** · **03-03-08, 10:22 PM**

I think I've seen that Mission-inspired sub posted somewhere. Very nice cabinetry! Is that one of your sealed models, or are you planning to build an LLT based on this design?

**tundraSQ** · **03-04-08, 05:11 AM**

Quote:

mrstampe wrote:

I think I've seen that Mission-inspired sub posted somewhere. Very nice cabinetry! Is that one of your sealed models, or are you planning to build an LLT based on this design?

I ran across that picture over in the HTGuide gallery. Its a downfiring ported design. I am going to a larger LLT version of that "look". Somewhere in the area of 30"high 36" wide and 24" deep. I can get 4 visable sides cut from a single 5x5 sheet of BB. the top and bottom and bracing will be MDF.

I have not decided where the sub and port will live yet. downfiring or side firing.

**tundraSQ** · **03-04-08, 05:12 AM**

Quote:

Warmon wrote:

Most people are using the "egg crate" mattress foam from Wal-Mart. I agree with you, I wouldn't use fiberglass either. The pic in your first post - is this your inspiration?

thanks egg crate it is...and yes that is not my sub, but I am using it as a guide. I saw that over at HTGuide.

**tundraSQ** · **03-06-08, 07:25 PM**

Today was spent tracking down some wood to build this thing with. I had received a quote yesterday for some BB..$72 for a 5x5 sheet and $89 for a 4x8 sheet...PLUS a $20 charge because they didn't normally stock that.

So I started looking into other options and other suppliers and came across a couple other BB type plywoods...appleply and europly. I could not find a dealer of appleply in my area, but I did find a 4x8 sheet of europly for $131.
That was the bad news....but the good news was this same dealer had 3/4" 5'x5' sheets of BB for $56 a sheet delivered...so it looks like thats the winner...but it won't be delivered for a week...but that should give me time to order in all the parts

**tundraSQ** · **03-06-08, 09:05 PM**

final size will be 11.5cu ft internal airspace "minus" whatever a 6"x27 in port will take up....and minus what the TC2000 takes up....is this big enough? I just figured it out to be 20" by 28.5" x 38.5" internal air space....so out of that space I need to subtract 3 braces....and one port...and one driver

**tundraSQ** · **03-09-08, 07:32 AM**

I keep thinking that with the LLT design i will lose too much "kick in the gut" sound.....so I am going to seriously consider ramping down to the something smaller.......I have my eye on the slot loaded 8 cuft design that army made for the SDX15....I wont have wood in hand until thursday so i still have time obsess ad nauseum

**SteveCallas** · **03-09-08, 01:15 PM**

If by "kick in the gut" you mean a less damped driver that will ring more and rolloff sooner, then yes, smaller with a higher tune is the way to go.

**tundraSQ** · **03-09-08, 03:57 PM**

Quote:

SteveCallas wrote:

If by "kick in the gut" you mean a less damped driver that will ring more and rolloff sooner, then yes, smaller with a higher tune is the way to go.

i'll take that as a "build the LLT and THEN if you don't like it build something else"

**tundraSQ** · **03-10-08, 08:26 PM**

OK.. getting down to crunch time....I figured out the FINAL cut list using 2 sheets of 5'x5' baltic birch. Internal volume comes out to 11.37..thats seems to be the largest I can make the box with 2 sheets. I still need to subtract the port area from that total....so the question is..

1. How do I calculate that?
2. How do I calculate what port length to even use with this size box?
3. How does this look so far? I feel like I am going to end up on the small side of a true LLT

The things I do no is that the internal dimensions are 18.5" x29.5"x36" (39 inches overall but I am subtracting 3 inch's based on 2 end pieces and 2 braces...each being .75" thick)

**Mike P.** · **03-10-08, 08:47 PM**

Box volume is 11.37 cu. ft. What tuning frequency do you want and what diameter is your port?

**tundraSQ** · **03-10-08, 08:51 PM**

Quote:

Mike P. wrote:

Box volume is 11.37 cu. ft. What tuning frequency do you want and what diameter is your port?

I may have answered my own questions....if it really is this simple:

http://www.bcae1.com/spboxnew2.htm

To came up with 15hz would need a port of 26.5 inches x6" and my total internal volume would dip to just about 11cuft.

**Mike P.** · **03-10-08, 09:03 PM**

Your numbers look right. When you start your build make sure you take lots of pics!

**tundraSQ** · **03-10-08, 09:10 PM**

Quote:

Mike P. wrote:

Your numbers look right. When you start your build make sure you take lots of pics!

Thanks...I will be sure to take lots of pics...wood should arrive Thursday and I will cut it up at work so as to be able to fit the pieces in my honda civic..plus I have a powermatic 66 5HP saw and a cnc router at work and only a delta contractor saw and jigsaw at home...

**tundraSQ** · **03-14-08, 08:55 PM**

Update: I have the wood cut...and I think I maxed out the 2 5'x5' sheets. I ended up with a piece about 18"x3" as a drop

Final Final internal measurements will be 18.5 x 28 x39.5. Adding in 2 internal braces and factoring in the driver and port is seems my net internal volume will be 10.658 and in order to tune this thing to 14.5hz i will need a port 6" long and 29.5" long... cutting that port by 2 inches raises the tuning to 15hz.

Heres my question....not having a computer to do any modeling....and the size of he box being the fixed size...is there a "best" port and/ or port lenght to use for this sub?

Pics to follow tommorrow

**tundraSQ** · **03-15-08, 08:07 AM**

first two pics

**SteveCallas** · **03-15-08, 12:18 PM**

Not a big deal at all, but with the final internal volume coming out to be 10.7 cubes, if you want to be a perfectionist, I'd probably make the port 26" long to raise the tune just over 15hz, as it yields a little stronger FR.

**tundraSQ** · **03-15-08, 12:27 PM**

I DO want to be a perfectionist , or at least as close as I am able to be. @6" sounds great to me, thanks!
Now I am downfiring the sub and would love to downfire the port for aesthetic value, but the height internal is only 28.5 plus 1.5" baffle leaves me 30"....leaving only 4" above the port. So now I need to come up with a solution...port it out the side, which will fire into a wall, I will have 6" or so between the side of the sub and the wall....or do I try to find a 6" elbow somewhere in vermont

**SteveCallas** · **03-15-08, 01:28 PM**

Elbows increase turbulent air flow. You should be able to mount the port at an angle inside the sub and have enough clearance. Also, shortening the port by an inch or two wouldn't be the end of the world

**tundraSQ** · **03-15-08, 02:19 PM**

cool..I never thought about angling the port...

**tundraSQ** · **03-15-08, 03:13 PM**

After mulling this over I think I am just going to port it out the side instead of trying to calculate the angle and how to cut the braces to support the port. This way I will be able to cut 6" inch holes for the port in the two internal brace pieces and the side piece on the CNC router all at once. I just wish I could find 6" flares someplace

**SteveCallas** · **03-15-08, 04:07 PM**

A 1" roundover bit will work.

**tundraSQ** · **03-15-08, 06:07 PM**

Looking for a 1" roundover bit seems to be a challenge as well....at least one that isn't going to cost me $100 bucks.

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