I am going to build a subwoofer.

[Number1]

See next post for actual project.

Context:

Here is my current system:

Receiver: 5.1 Sony STR-K900 OK for now, I hate the fact it doesn't have bass and treble adjustment knobs. I am using the small speakers this unit came with with the Rurabrand home theater/DVD player upstair.

Subwoofer: SonySW-WP780, 8", underwhelming and the port is really noisy.

Front A: Cerwin Vega 12 in 3 way. They don't have the original woofer and they sound a bit like a tin can. I am on the lookout on Kijiji for replacement woofer and I am in no hurry. There is always a pair of Cerwin Vega for sale somewhere.

Front B: Wharfedale E70: Not used for now. I picked those up Monday for $40.00. They sounded pretty good at the guy's place but when I got home I realized the 4 mid ranges needed re-edging. I ordered 2 kits and this should be here in 10 to 15 days. Darn shipping from the States to Canada cost $25.00 :-(

Centre: Bastard I made myself from parts laying around. I am on the lookout on Kijiji for a better one or I will build a new one eventually.

Rear: Pioneer 4 way CS-J825Q towers. I will replace them with the wharfedales or cerwin vega once I have the Whaferdale fixed. They are going into storage ASAP.

TV: Hitachi Ultravision 42HDS69 Plasma 1080i

Cable Box: Motorola DCT6416 III HD DVR.

PC: See sig, hooked up to the TV via HDMI. Audio from motherboard is linked to the receiver via optical SPDIF for movies DD and DTS. I built and use a Multi channel cable for games.

Pictures Gallery.
Password is : AnandTech

This setup sounds OK. I think a good subwoofer could make a significant difference when watching movies and listening to music. I can work with wood, MDF is cheap, and I have a lot of room.

See next post for actual project

 

[Number1]

I like to watch movies and listen to music so I decided on a vented box design for the extra bass. Hopefully this thing will be able to shake the frames off the walls.

I have no experience at building subwoofers and I don't know much about it. I have been reading on the net for the last few days and been experimenting with BassBox 6.

The budget is fairly limited so the cheaper the better.

These are the parameter I ended up with using the software:

Fb: 18.04 Hz
F3: 22.83 Hz
QL: 5.792


Volume: 6.844 cu ft.

Vented box 36.86" X 22.78" X 14.08" inside dimension.

Vent, double flared 3" pipe 7.66" long.

No damping material inside the box.

6 internal braces .75" thick and 2" wide, 2 each on each X Y Z axis. I have provided for this volume in the calculations.

The Amp will be mounted on the rear of the box in an 8.5 X 8.5 cut out. I have provided for this volume in the calculations.

Walls: 2 layers of .75" Medium Density Boards (MDF) glued and screwed together for a total thickness of 1.5".

Electronics:

Subwoofer: Dayton DVC385-88 15" DVC Series $142.62 The Qts is .36, well suited for a vented box.

Amp: Dayton SA240-B 240W Subwoofer Amplifier with Boost $109.00

Vent: Precision Port 3" Flared Port Tube Kit $12.25

Total for electronics $272.00 plus shipping and taxes.

If anybody has any experience building these feel free to comment and make suggestions.

A few questions:

Damping material: I don't plan on using any. What are the pros and cons?

Would thicker bracing inside, say 1.5" instead of .75 make a difference in the rigidity or the box? Since I will be using 1.5" walls do I even need bracing?

Can gluing and screwing panels of MDF together cause problems like rattling? I will be using regular wood glue and drywall screws and pre-drill all the holes to keep the MDF from splitting.

Does the box needs "feet" or is it better just to place it directly on the floor?

I want to order the parts before the 28 of Jan.(the sale ends at part express). I wonder if they ship free to Canada? ya right!!!!

I will have access to a table saw and start building the box next weekend. I have never build something that needs to be this precise so I will be taking my sweet time measuring 4 or 5 time and cutting once. The centre speaker I built turned out looking OK but I will need to be more precise for this project.

 

[Nohr]

I look forward to seeing your project. Anything you build can only be better than the Sony subwoofer.

 

[vi edit]

Since you are in Canada, look at the CSS driver
http://www.creativesound.ca/details.php?model=SDX15

They have a sealed build on their sheet. These things can also flatten a house in a sonotube or large (9 c/f) ported boxes with 1000 watt amps stuck to them.

 

[Number1]

Since you are in Canada, look at the CSS driver
http://www.creativesound.ca/details.php?model=SDX15

They have a sealed build on their sheet. These things can also flatten a house in a sonotube or large (9 c/f) ported boxes with 1000 watt amps stuck to them.

Wow they have nice stuff on that site. Ill be checking it out.

 

[YOyoYOhowsDAjello]

You want this
http://www.avsforum.com/avs-vb/showthread.php?t=1189404

Danley DTS-10 "Super Spud"

 

[Number1]

You want this
http://www.avsforum.com/avs-vb/showthread.php?t=1189404

Danley DTS-10 "Super Spud"

Awesome and a good read but the WAF is insurmountable here LOL.
Then there is the price at about $1000. plus shipping.

Ill stick to my design unless somebody can show me something better or how to improve it at a comparable price.

 

[YOyoYOhowsDAjello]

Awesome and a good read but the WAF is insurmountable here LOL.
Then there is the price at about $1000. plus shipping.

Ill stick to my design unless somebody can show me something better or how to improve it at a comparable price.

Awww, I wanted to see the first Anandtech member build one

 

[tweakboy]

That's a fun project. I read your long post. Those are good parts and good size.
So your going to put 2 sub woofers back there, have you decided on that yet ?

You will need a dedicated amp for the woofer, and another amp for speakers.. let us know.. gl

 

[vi edit]

I'd personally go with a different driver. The CSS one I linked to save on shipping is a very highly reguarded one. It's just a much better built, beefy driver than the Dayton. And I'd do a 500 watt amp with it.

You don't need to double up/laminate the sidewalls of the box. .75" MDF/Ply is fine. I'd only double up the front baffle so that you can go flush mount with the driver. And yes, you need internal bracing. A simple "window" brace across both sides would be sufficient.

Here's a 12" Dayton RS-HF sub that I built:
http://pics.bbzzdd.com/users/viedit/sub9.JPG
http://pics.bbzzdd.com/users/viedit/sub8.JPG
http://pics.bbzzdd.com/users/viedit/sub10.JPG

 

[Number1]

I'd personally go with a different driver. The CSS one I linked to save on shipping is a very highly reguarded one. It's just a much better built, beefy driver than the Dayton. And I'd do a 500 watt amp with it.

You don't need to double up/laminate the sidewalls of the box. .75" MDF/Ply is fine. I'd only double up the front baffle so that you can go flush mount with the driver. And yes, you need internal bracing. A simple "window" brace across both sides would be sufficient.

Here's a 12" Dayton RS-HF sub that I built:
http://pics.bbzzdd.com/users/viedit/sub9.JPG
http://pics.bbzzdd.com/users/viedit/sub8.JPG
http://pics.bbzzdd.com/users/viedit/sub10.JPG

Wow nice work on your cabinet. I don't intend to build anything this nice. I am going to follow your advise and not double up on the MDF but put a lot of bracing in the box.

The shipping fees and custom fees from PE are outrageous so I am going to get my parts from a Canadian site. CSS as you suggested looks good.
I have to keep the cost for the electronics as low as possible, between $300 and $400 including shipping so the 1000 W amp and SDX15 drivers you suggested are out of the question.

I think I can build a decent vented box with the following parts:
CSS TRIO12 $144.00

CSS BASH300 $160.

3" flared port $17.00

Shipping $44.00

Total $365.00 plus taxes

Some of CSS's trio kits retail for this approximate price but the drivers are much smaller. They use passive baffle and I have no idea how those kits would perform compared to a vented box with a 12 in sub.

The SDX10 driver is affordable but does not compare favorably in Bassbox 6 to the TRIO12. The SDX15 had a somewhat better frequency response then the trio 12 but the trio12 is $100 cheaper.

BassBox recommends a vented box of 4.038 cu Ft (Vb) for the TRIO12 driver. Would building a bigger box have a negative impact?

 

[Number1]

I could do it the easy inexpensive way and get this

Pioneer Subwoofer

 

[vi edit]

I don't really know much about the trio. I do know that you are better off spending a wee bit more right now and being happy than having buyers remorse a few months down the road. I haven't modeled that 12" trio driver but a 3" port for a box that size seems small. The box I built was around that size and with a 4" port was tuned for around 20hz. I'm thinking that this is probably going to wind up in the 25hz to 30hz range, no? That's just not where you want to be if this is going to be a HT sub.

The price difference between the 12" and 15" isn't *that* much in the grand scheme of things. But the output is pretty considerable. I bought a 12"..should have listened to others advice. I now have a 15" sub. And looking to move up to a couple 18" in an infinite baffle arrangement for my next setup.

Here's a nice looking "sealed" build of a 15" driver.

 

[vi edit]

Oh, and here's a sweet SDX15 build

http://www.hometheatershack.com/for...974-first-subwoofer-build-css-sdx15-pics.html

 

[Number1]

Oh, and here's a sweet SDX15 build

http://www.hometheatershack.com/for...974-first-subwoofer-build-css-sdx15-pics.html

The link is broken

Ill post the modeling information for the TRIO12 soon.

 

[Number1]

I modeled the TRIO12 using WindISDpro .50a7 and BassBox 6.

I ended up with a 4.256 Cu Ft box.

Tuning freq is 20.73 Hz in WindISD and 18.78 Hz in BassBox

The vent is flared at both ends and is 3" in diameter. WindISD recomends 7.84" and BassBox 11.73" in length.

I want to use the biggest vent tube I can but the most practical diameter is 3" . The bigger the tube, the longer it needs to be. Would there be much difference using a bigger tube? How about using more then one vent?

For all the technical data and graphs, see my SmugMug gallery page 2 and 3.

I am going to model the SDX15 sometime today and see how it compares.

 

[vi edit]

Check your port velocity. At that tuning and port size you wil probably have very significant "chuffing".

 

[Number1]

CSS TRIO12 versus CSS XDS15.

The TRIO requires a 4.256 cu ft box. The tuning frequency (Fb) is 18.78 Hz. F3 is 19.75 Hz (BassBox)

The XDS15 requires a 7.769 cu ft box. The tuning frequency (Fb) is 17.4 Hz. F3 is 20.36 Hx (BassBox)

How much of a difference in sound would there be between the 2 boxes?

 

[Number1]

Check your port velocity. At that tuning and port size you wil probably have very significant "chuffing".

It is significantly higher then with the XDS15 box design but I also modelled it with a 4 in flared tube.

Ill experiment with this and see how much I can lower it.

 

[Number1]

Here are some measurements with a 4 in Vent. The peak speed went from 47 to 26 in BassBox. 72 to 40 in WindISD.

 

[vi edit]

Definitely try to get that port velocity below 30. If you can't do it with a 4" pre-made port tube, then maybe look at doing a slot port.

 

[Number1]

Definitely try to get that port velocity below 30. If you can't do it with a 4" pre-made port tube, then maybe look at doing a slot port.

Sounds good. Let me work on that.

 

[Number1]

OK so far here is my solution.

CSS TRIO 12

BASH300 Sub Amp

Box: 4.256 Cu Ft
Size: 21" X 15" X 26.88"
Tuned to 18.78 Hz
F3: 19.75 Hz
Vent: Square 3.75", 23.08" long (BassBox) or 22.52" (WindISD)
Internal bracing.
No fill.

 

[Number1]

I had a look at all the Car subwoofer driver on sale at Future Shop and modeled most of them in BassBox.

Nothing come close to the performance I get out of the CSS TRIO12 at any price except maybe for the Infinity Karppa 122.7w
The problem with it is the cone excursion (Xmax) is only 12mm compared to 20 for the TRIO.
The Qts are similar, .456 compared to .43 but the killer problem is the $200.00 price tag.

All and all, the TRIO is a better deal at $144 plus shipping.

I reduce the vent air velocity in my TRIO box SIGNIFICANTLY from about 21 M/sec to a bit above 12 M/Sec by changing the dimension from 4" X 4" X 26.56" to 1.75" X 15" X 47.6"

This is a much longer and bigger vent. I simply use the bottom and back walls of the box to form one side of the vent.

I have seen this design in commercially available subwoofer so I would imagine it will works well.

As of now the box will measure 23" X 15" X 30.04". Big but manageable for my room.

 

[Number1]

I ordered the Amp and Driver today from CSS
Total $381.94 including shipping and taxes.

BASH300
TRIO12

I also purchased some hardware at the local store

Wood Glue
T-Nuts, bolts and washers to fasten the driver.
Saw Guide
SheetRock screws
Drill bits for the T-Nut and for pre-drilling the screw holes.

Total for hardware $42.43

Ill get the 3"MDF sheet tomorrow and start building the box.