DIY Subwoofer: Would like some feedback!

**hddummy** · **09-12-07, 05:52 PM**

Hey guys. I've been around here before, but I've never really been an active member. I recently built myself a sub and I wanted to get some feedback from you folks. This project is done, but I could apply suggestions and advice to the next DIY I am planning to build for my brother-in-law.

Anyway...I love the way this thing turned out...it has a tremendous amount of bass and it makes me grin ear to ear every time I crank it up.

The stats:
TC 12db-500
115 Liter enclosure
Two 3" x 17" ports
Tuned 21.8 Hz
Walls lined with fiberglass batting
Butt Kicker Amp with 25Hz HP

One of my concerns was whether or not I should have used more internal bracing. Questions/Comments? Thanks for checking it out!!

**Geoff St. Germain** · **09-12-07, 06:00 PM**

Welcome to the Shack!

That's a great looking project... a great design to take advantage of the unused space behind the TV. The dB-500 is a great driver... especially for the price.

I would probably have added a couple of more window braces. If it sounds great, that's all that really matters though.

What paint did you use to finish it?

**WillyD** · **09-12-07, 06:08 PM**

I think I've seen this build somewhere before! I really dig it because it displays one of the best things about DIY...being able to fit a device to your particular situation. You wanted a sub but had to keep it hidden, so you built it to fit like a glove in the corner. Perfect!

Enjoy.

**Mike P.** · **09-12-07, 06:09 PM**

For the size and shape I'd say it's braced adequately. One way to tell for sure is play low frequency test tones and feel the cabinet with your hand to see how much vibration there is. A well braced cabinet will vibrate very little.

**JCD** · **09-12-07, 07:02 PM**

First, great execution!

As for the bracing, I have nothing scientific to back this up, but I might have added at least one more internal brace.. and if I were feeling frisky, I'd add two.

Again, just a gut feeling with absolutely nothing to back it up with..

JCD

**Sonnie** · **09-12-07, 07:08 PM**

Excellent build...

I liked how you adapted it to your situation and room.

**hddummy** · **09-12-07, 10:01 PM**

Thanks for the good woods guys!!! I appreciate you advice. I was thinking one more frame brace similar to the one at the bottom of the ports would have been helpful. I ran out of MDF and I thought...aaahhh go for it.

Germain: That is Rustoleum Flat Black Latex Paint. I didn't bother getting fancy since it is hidden from view anyway. I just wanted something to protect the MDF from humidity and such. As for sounding great....I like it, though you can see what I upgraded from in the first picture. Anything would sound good by comparison. I bought the db-500 because I thought it was a great value. I just bought TC's last one in stock because I now know it is a great value. I'll keep that one tucked away for a year or so until I start building a dedicated theater room.

WillyD: A few weeks ago, I posted pics over at AVSForum. You probably saw it there.

Others...thanks for the replies.

**Exocer** · **09-12-07, 11:15 PM**

Quote:

hddummy wrote:

Thanks for the good woods guys!!! I appreciate you advice. I was thinking one more frame brace similar to the one at the bottom of the ports would have been helpful. I ran out of MDF and I thought...aaahhh go for it.

Germain: That is Rustoleum Flat Black Latex Paint. I didn't bother getting fancy since it is hidden from view anyway. I just wanted something to protect the MDF from humidity and such. As for sounding great....I like it, though you can see what I upgraded from in the first picture. Anything would sound good by comparison. I bought the db-500 because I thought it was a great value. I just bought TC's last one in stock because I now know it is a great value. I'll keep that one tucked away for a year or so until I start building a dedicated theater room.

WillyD: A few weeks ago, I posted pics over at AVSForum. You probably saw it there.

Others...thanks for the replies.

Hmmm, dedicated HT room and two db-500's, sounds like maybe a dual ported sub is right up your alley? for the future larger room of course

Great job overall. If only my DIY projects looked so nice.

**hddummy** · **09-13-07, 06:23 AM**

I was thinking dual LLTs actually. My initial calculations show very promising response curves and that ButtKicker amp can definately handle both drivers at once. Though, that is another project for another day. I'll be sure to post all about it when the time comes.

**SteveCallas** · **09-13-07, 11:53 PM**

Sub looks fine - looks like 1" MDF, and with an enclosure that large for a 12" driver, pressure against the walls shouldn't be bad at all, so you should be fine without any additional bracing.

That said, the black levels and contrast on your display looks a little troubling

**Kermie** · **09-14-07, 12:03 AM**

hddummy,

I have been looking for a project just like yours for both my left and right front corners of the HT.

Can you tell me how you decided on the volume of the cabinet. I am looking at doing a down firing sub with the port facing forward firing towards the room (HT)

I have about 24 inches for the face of the triangle and about 17 inch for side A and B.

What are the dimensions of your sub?

**Mike P.** · **09-14-07, 01:30 AM**

Hi Kermie,
I'm "uklit" from AVS. I'm glad this is what you were looking for. What sub driver are you thinking of using for your corner subs?

**Fred33** · **09-14-07, 09:09 AM**

Welcome to the shack. Really like the use of shape and how you worked everything into a corner. Very cool.

**Kermie** · **09-14-07, 09:36 AM**

Quote:

Mike P. wrote:

Hi Kermie,
I'm "uklit" from AVS. I'm glad this is what you were looking for. What sub driver are you thinking of using for your corner subs?

uklit, thank you for this link. i think the largest i could fit would be a 12 inch. I have to look into a brand. I will have one in each corner of my front wall and have a Crown XLS 402 to run them both.

**Mike P.** · **09-14-07, 11:56 AM**

Just remember that the internal volume of your cabinets is 3.5 cubic feet. That will narrow down your choice of available sub drivers that you can use.

**Kermie** · **09-14-07, 01:56 PM**

typically how much cubic feet do bracing take up and the port.

do subtract the about of wood used in bracing and the whole port (If concidered a solid) from the over all cubic feet?

also can you expand on the choices of drivers?

thank you

**Mike P.** · **09-14-07, 03:02 PM**

typically how much cubic feet do bracing take up and the port.

That depends on how much bracing you use and how big the port is.

do subtract the about of wood used in bracing and the whole port (If concidered a solid) from the over all cubic feet

Technically yes. You can figure out every cubic inch and subtract it to get the net volume. Or you can build a box 1 cubic foot bigger then needed to allow for the displacement of the subwoofer, bracing and ports. In your case you know the biggest internal volume you can build is 3.5 cubic feet. So find a sub that will work in a slightly smaller net volume.

also can you expand on the choices of drivers?

Off hand, I'm not sure which driver would meet your needs. Hopefully someone else who is familiar with 12 inch subs can make a recomendation. You can download WinISD and do some simulations if you're inclined to.
http://www.hometheatershack.com/foru...30-winisd.html

thank you

Anytime.

**Joe L.** · **09-15-07, 07:38 AM**

Great use of the unused space behind the TV. Very nice adjustable stand for the TV too.

You were not really limited to 3.5 cubic feet unless you wanted the sub to be below the level of the equipment rack. You probably could have fit a much larger enclosure back there if you had made it taller.

If made taller, you could then have painted it the same color as the walls in the room instead of black, and it would have been nearly invisible to anyone looking at it through the equipment rack.

Of course, if you made a bigger/taller enclosure, you would need more bracing.

Joe L.

**Mike P.** · **09-15-07, 07:57 AM**

Quote:

Joe L. wrote:

Great use of the unused space behind the TV. Very nice adjustable stand for the TV too.

You were not really limited to 3.5 cubic feet unless you wanted the sub to be below the level of the equipment rack. You probably could have fit a much larger enclosure back there if you had made it taller.

If made taller, you could then have painted it the same color as the walls in the room instead of black, and it would have been nearly invisible to anyone looking at it through the equipment rack.

Of course, if you made a bigger/taller enclosure, you would need more bracing.

Joe L.

Just to clarify, the pictures are of Matt's subwoofer. It is Kermie who wants to build a similar shaped sub and he is limited to 3.5 cubic feet.

**Joe L.** · **09-15-07, 10:11 AM**

Thanks for the clairification.
I understood it is Kermie who wants to build similar shaped enclosures for subs in the front corners of his Home Theater. He gave 17 inches for the left and right sides, 24 inches across the baffle, but did not specify the height. If the enclosures don't have a screen have above them, he may not be limited to 3.5 cubic feet volume, since the enclosure height may be adjusted accordingly.

I built a 260 Liter sonosub using an 18" diameter Sonotube and a 6" port out the top tuned to just under 17 Hz. It is not very much different in its footprint on the floor than his proposed enclosures with 17" sides. It is a lot more than 3.5 cubic feet internal volume since it is 6 1/2 feet tall.

I can tell him about one thing for sure. Corner placement will result in a LOT of bass coupling to the adjacent walls. If there are doors, pictures, or anything hanging on the walls nearby, they will rattle.

I had to weatherstrip my closet doors when I put my sonosub in the corner adjacent to a wall. They easily rattled in their frames until I put the weatherstripping in place. I even had to wrap the same foam around the doorknobs shafts, so they would not rattle as the door vibrated. (I was using a 15" Adire Tempest driver that displaced 2.5 liters of air.)

Moving my sub a foot or so away from the corner made it bearable in my room.

Joe L.

**hddummy** · **09-15-07, 11:48 AM**

Sorry...can't respond right now.....I'll be busy for a week or so. I just didn't want to leave everyone hanging. I'll get back to you when I can.

**Kermie** · **09-15-07, 09:24 PM**

Quote:

Joe L. wrote:

Thanks for the clairification.
I understood it is Kermie who wants to build similar shaped enclosures for subs in the front corners of his Home Theater. He gave 17 inches for the left and right sides, 24 inches across the baffle, but did not specify the height. If the enclosures don't have a screen have above them, he may not be limited to 3.5 cubic feet volume, since the enclosure height may be adjusted accordingly.

I built a 260 Liter sonosub using an 18" diameter Sonotube and a 6" port out the top tuned to just under 17 Hz. It is not very much different in its footprint on the floor than his proposed enclosures with 17" sides. It is a lot more than 3.5 cubic feet internal volume since it is 6 1/2 feet tall.

I can tell him about one thing for sure. Corner placement will result in a LOT of bass coupling to the adjacent walls. If there are doors, pictures, or anything hanging on the walls nearby, they will rattle.

I had to weatherstrip my closet doors when I put my sonosub in the corner adjacent to a wall. They easily rattled in their frames until I put the weatherstripping in place. I even had to wrap the same foam around the doorknobs shafts, so they would not rattle as the door vibrated. (I was using a 15" Adire Tempest driver that displaced 2.5 liters of air.)

Moving my sub a foot or so away from the corner made it bearable in my room.

Joe L.

I am sorry, I didn't want to hijack this thread for my stuff. I just love the corner sub idea. the height i have to work with is 36 inches. I am limited. It will be roughly 3.2 cubic feet (17x17x36)/2 for volume

**Owen Bartley** · **09-18-07, 01:47 PM**

Nice build Matt. I know that most sub material is "omnidirectional" but in reality, I think most people can localize subs, so I bet it's nice having it directly behind your TV. That's the most appealing thing to me about the custom TV stand, etc. subs.

**hddummy** · **09-24-07, 11:50 AM**

Ok...I'm back....let's see what we've got.

Enclosure is made from 3/4 MDF. I cranked it up the other day and put my hand on the outside to feel for vibration. I didn't feel too much vibration compared to the rattling in my head from being that close, so I guess I'd say it is built well enough.

Black levels on the plasma look awful because the camera flash reflected off of the screen and those pics are artificially brightened so you can see all the goods. It is actually calibrated quite well using both Avia and DVE.

When I designed this enclosure, I was looking for the volume that would give me the flatest anechoic response. I don't think I get much room gain since my living room is part of a large open floor plan common to the dining room, kitchen, foyer and stairs. I also didn't want a super large enlcosure because that would increase my risk of pushing the driver past it's excusion limits with the amount of power my amp has. Although I could have made it as much as 1.5 cuft larger because I wasn't limited by height, I am please with the final result.

Thanks for comments on the TV stand...That was another of my projects. I didn't trust the base that comes with the TV and there are no wall mounting options when the TV is in a corner. I also like it because you can't easily see the stand from the front, so it looks like the screen is just floating there. Not to mention it would take at least 30 min for a thief with the right tools to try and make off with my plasma because that sucker is bolted down.

Base coupling to the walls....uhm..yeah. the windows to the right rattle like you wouldn't believe if I crank it up high enough....which is almost any movie that I watch when no body else is home.

No worries about discussing other projects here. That's the idea..to help everyone accomplish their subwoofer dreams.

**Owen Bartley** · **09-24-07, 01:20 PM**

Matt, how about a few pics of your stand? I didn't even notice it first time around, but after reading your comment above I went back to check it out and it does look really cool. Could you give us some more details on it?

Advertisement