first diy sub project.....help needed!

[Meteora_LP]

hey guys im new to this forum and this whole diy thing!

i just recently bought myself a surround sound setup. the only thats missing is a sub :P

so instead of just buying some cheap subwoofer from futureshop or best buy i wanted to build one myself. i would like to limit my budget to maximum 400$ or lower. i love huge bass sound when i listen to my music....and i like to listen to all genres of music.

i would like to build a subwoofer for 80% music and 20% movies.

ive been surfing around the web and tried to research as much as i could but in the end it just got a little confusing with all the calculations and t/s parameters and all the software programs there are......

DRIVER
what i need to get is a driver and amp and i will buy the sub enclosure myself.
ive been looking at the Dayton DVC310-88 12" DVC SERIES SUBWOOFER and the DAYTON RSS315HF-4 12" HIGH FIDELITY SUBWOOFER. I honestly dont know the difference between the 2. any suggestions and advice?

AMP
what plate amp should i get? and what wattage? should i get a dayton to pair up with the dayton? i was planning to get the 250W amp from dayton, is that enough power for the driver? again, any suggestions and adive?

SUB ENCLOSURE
how do i design the enclosure? are there any good software programs that i can use? what material should i use? should i go sealed or ported?

please help and thank you!!!

[ThomasW]

First question, $400US or $400CDN?

Second question how big a box can you live with?

Sealed or ported basically depends on the size of the box. If you can live with a bigger box then ported becomes a possibility. If you want a small box then your only choice is sealed.

There are other options in drivers. One is the 12" TC2+ from www.oaudio.com. Another option is the AV12" from www.aespeakers.com/

[Meteora_LP]

hey and thx for ur reply
$400CDN and i guess ill go with the sealed! however, i dont want a super high quality audiophile sub, just something that is powerful and loud from a range of something like 19-60Hz without distorting. wouldnt one of the dayton drivers be good enough for that? im just asking because they are cheaper right now....and please tell me if there is a big performance gap between the drivers u suggested and the daytons.

also, wat plate amp would go along with these drivers? is 250 watts enough?

what is the difference between single voice coil and dual? is dual louder?

[ThomasW]

Okay that's ~$345USD

For subs it's all about how much air they can move. That means the driver with the highest Xmax wins.

The 12" TC2+ Oaudio driver has the highest Xmax. That means it will play the loudest and handle the most power

If you can afford the 300 or 500 watt BASH amp would be best. The 240/250 watt amps will work, but won't play as loud.

For your use there's no difference between a SVC and DVC driver.

[Meteora_LP]

ok sounds good, but if the 12" TC sounds TC2 DVC is only 5$ more than the SVC, shouldnt i buy that instead of the SVC?
and for what use is there a difference between DVC and SVC?

[Brian Bunge]

You'll want the SVC. It has a single 4 ohm VC, whereas the DVC has dual 4 ohm coils. You'll either have to wire them in series for an 8 ohm load, which will reduce output from the amp, or wire them in parallel for a 2 ohm load which will cause the amp to overheat and probably shut down during bass heavy passages in music and movies.

[ThomasW]

:agree: ....

[Meteora_LP]

alirght! now that we got the driver and amp figured out i decided to go along with these 2:
Driver: 12" TC Sounds TC2+ SVC -------------$139US
Amp: BASH DIGITAL SUB AMPLIFIER 300W ----$150US

ok lets talk about the enclosure.....

[J-Dub]

Hi, Meteora!

I'm happy to hear you have found your driver and amp!

Thomas & Brian will correct me if I'm wrong but 19Hz-60Hz sounds like it is geared more toward home theater than music. If I'm not mistaken I think you are probably looking for something more in the range of 30-150Hz with the possibility of going down to 20 Hz for music.

In my experience sealed subs sound great for music but need a lot of power to get down low. This is probably your easiest choice. Ported subs have the ability to "dial in a tuning through the port and will require less power in that tuning range to get louder results if that is what you are looking for.

Good luck with the project!

[ThomasW]

In post #2 ..

How big a box can you live with?

[Meteora_LP]

hmmm i guess i wouldnt want the measurements to exceed 50cm in length, height or width....so i guess the box would be big enough to accommodate a port?

and according to Jdub ported subs are better for producing lower frequencies when u have less power wattage so should i go with a ported box?

[ThomasW]

Ported boxes provide more output at the tuning frequency compared to a sealed box. Ported boxes are slightly more efficient, so they do better with less power

If your 80% music/20% movies statement is really what you want, then a sealed box is the better choice.

To tune a box to reasonably low frequencies one needs ports that are ~25" or so long. That's a bit of a problem in a 50cm box.

I think you are probably looking for something more in the range of 30-150Hz with the possibility of going down to 20 Hz for music.

Subs should be run as low as possible, 150 Hz is to high for any sub.

[Meteora_LP]

ok then a sealed box it is! what software programs do i use to calculate the box size?
and what material do i use?

[ThomasW]

Asking this for the 3rd time, how large a box do can you live with?

Fundamentally there's nothing to calculate with a sealed sub. You build the largest box you can comfortably live with.

[---k---]

So many threads about first time subs, it is getting difficult to keep them all straight. He said up there in post #11, that he was willing to go with a 50cm cube. I quickly modeled the TC2+, if I got it right, that looks about perfect.

Check out Unibox:

http://home20.inet.tele.dk/kou/ubmodel.html

It will let you model the size. But like Thomas said, with a sealed sub, bigger is better, but being slightly smaller than perfect isn't going to make a huge differance - it will still be good.

[ThomasW]

Oops my bad that's right. Okay then build a 50cm cube....

I'd make the box from either doubled 3/4" MDF or a mix of 3/4" MDF outer layer with a 3/4" OSB inner layer.

If you want a lighter weight box, use 3/4" Baltic Birch ply (1.5" front baffle) Note that BB ply is a 13 layer ply, not the cheap 5 layer stuff sold at the big box stores.

Use a bracing pattern something like this....

[Meteora_LP]

hi, im pretty new to woodworking so i am not totally sure what MDF or OSB is......are there any guides reguarding box building?
what glue do i use etc?
thx!

[ThomasW]

Google is your friend for generic stuff like this...

MDF = medium density fiberboard (not the same as particle board)

OSB = oriented stand board this is also called flake board

I use a standard yellow wood glue, so Titebond II or Elmers Professional Wood glue.

How you make the box depends on how you intend to finish it, and your woodworking skills.

Using nails or screws isn't the best idea with MDF since it tends to break. If you have a small air nailer then brads work well for holding the stuff in place while the glue dries. Otherwise use clamps.

MDF is nice because mistakes can be covered up with Bondo. The newest thing for noobies is to use truckbed liner as the finish coat. It's tough and hides a myrid of sins.

Look at our sticky thread called the "DIY subwoofer showcase" to see what others have done before you.

Sorry but trying to cover the complete construction of a sub step by step, isn't something I have the time or patience to do....

The link below shows a lot of info about the construction of a box sub

http://www.danmarx.org/audioinnovation/tcsounds.html

Also look through the sub threads on this forum. There's lots of info if you're willing to take the time to read them.

[Meteora_LP]

sowhen u say double MDF you mean that i glue two MDF boards together for each side of the box? and should the internal dimensions be 50cmx50cmx50cm according to k?

[ThomasW]

Yep doubled 3/4" = 1.5" thick surfaces if you're going to use MDF or a MDF/OSB combo.

Trying to assemble 1.5" thick pieces is difficult since they're so heavy

In the long run it's much easier to fabricate an outer box of 3/4" materials, then slide in the inside pieces to make the total wall thickness 1.5"

50cm are the interior dimensions if you want optimal performance.

[Meteora_LP]

should i make the holes for the driver/amp on each separate layer of MDF? or should i cut the holes on the two layers at the same time?

would two of the braces that u have shown me be enough?

[ThomasW]

Completely assemble the box, then cut the holes.

Two braces will be fine.

[Meteora_LP]

I have 2 more questions:

-with what tool and how do you cut the perfectly round hole for the driver?? a jigsaw? if so, how to do you cut the perfect looking round hole? do you just do a rough cut and then smoothen it down with a router or sandpaper?

-can i smoothen down the edges of the box without any problems or would that weaken the whole structure?

[---k---]

A Plunge Router with a jig is best. Thomas has an example on his website: http://home.comcast.net/~audio-worx/...tTutorial.html

But, many people have done it with a jigsaw. You just have to spend more time.

[chasw98]

I have 2 more questions:

-with what tool and how do you cut the perfectly round hole for the driver?? a jigsaw? if so, how to do you cut the perfect looking round hole? do you just do a rough cut and then smoothen it down with a router or sandpaper?

-can i smoothen down the edges of the box without any problems or would that weaken the whole structure?

When I built mine, I found it invaluable to make some test cuts with the router before doing it for real on the enclosure. Remember, if you assemble the cabinet and then cut the holes for the driver, you only get one chance or you will find yourself building a second box!

Chuck

[ThomasW]

For dozens of year I used a jigsaw. Once I bought a router and a circle cutting jig, I felt silly for not buying one many years earlier. I made up for it and own 4 routers now ...:wink:

If you have a router you can use a 1/2" -3/4" round-over bit to 'ease' the edges of the cabinet. This will also make the box appear smaller than it is..

[dyazdani]

Completely assemble the box, then cut the holes.

Two braces will be fine.

I am planning on making a 3 x .75 = 2.25" front baffle. Will I be able to get the upcut bit that deep without the collet or something hanging up? It doesn't look like it will work, but I obviously haven't tried it.

[ThomasW]

One trick is to use a router that has a 1/2" collett with a 1/4" bit adapter. The adapter can be used to lower the bit further than it would normally cut. But sorry not even this trick will cut through 2.225" thick material. Sooo...

Make the top layer a separate piece that's cutout before it's mounted.

[Meteora_LP]

ok thank you guys very much for all the input!!! i will keep you posted and ill be sure to ask anymore questions that pop up! haha this is gonna be so much fun.

Norman

[dyazdani]

One trick is to use a router that has a 1/2" collett with a 1/4" bit adapter. The adapter can be used to lower the bit further than it would normally cut. But sorry not even this trick will cut through 2.225" thick material. Sooo...

Make the top layer a separate piece that's cutout before it's mounted.

Thanks, that is what I was planning, but I thought someone might have a neat trick...

[---k---]

CJD helped me with my front baffles. He prefered to cut them without them attached to the box. This allowed us to flip it over and cut it from both sides to avoid the problem you are describing. Both ways have their pluses and minuses. So, practice with your new shiney router and see which way will work better for you.

[cbj]

I ended up cutting my front baffles (also 3 x 0.75") away from the box. The way I did it was to get the baffles lined up like they would be in the box and then drilled a hole through the center of the stacked baffles where the driver-cutout would be. Then once I cut the driver opening in each of the three pieces I just used the pre-drilled hole for my jasper jig. Sure enough the driver-cutouts all lined up. The reason I did it that way was so I could keep the clamped & heavy shells inside and just take the baffles outside to do the routing.

[Meteora_LP]

hey.....i just bought all the materials today and i was surprised at how heavy my sub is going to be lol......i estimate 100+ lbs.!!!!
anyways, i have two questions....
1. Do i have to stuff/line the sub with some dampening stuff?
2. Do i have to seal the subwoofer edge where it screws onto the MDF with rubber lining? also same for the amplifier? (to prevent leaking)

[ThomasW]

Sealed subs are stuffed with damping material at a rate of .5-1.5 lbs per cu ft of volume.

Fiberglass batting is best, if you don't like working with it use loose fill polyfill

Neoprene weather stripping tape works well for both the driver and the amp.

BTW you might want to read some of the other DIY sub threads posted here for anwers to these types of questions, since the answers are pretty generic.

[Meteora_LP]

hey!
ok i finally finished my subwoofer last night and all i can say is that it sounds better than awesome!!!!! i have it plugged into my home theater receiver via a subwoofer cable (LFE) and when nothing is playing my sub creates an annoying buzzing sound when the receiver is on, when i turn the receiver off the buzzing sound gets 2 times louder! how do i get rid of this problem?

i will post some pictures later

[SteveCallas]

Try a cheater plug on the amp.