Where do I start?

[twowheeled]

Hi everyone, this is my first post on diyaudio. A few years ago I dabbled in DIY, built a pair of book shelf speakers as well as a very crude cabinet for some subwoofer drivers I was given for free. I'm interested in building a real subwoofer this time but I don't know where to start. This forum contains a huge amount of information but it all seems very disorganized, where would I brush up on recommended reading as well as some of the popular choices out there people are building? What would be great is if I could find some sort of listing outlining cost/complexity and performance of the popular DIY subwoofers.

In any case, here are some general goals I have set.
-use for home theater and stereo listening
-powering an 18x30 foot room enclosed by 3 walls
-cabinet size can be reasonably large but would perfer a box design rather than tubular
-performance down to 20hz, I will also be adding bass shakers to the couch for low freq's.
-build cost $500-800 drivers and amp

[nunayafb]

Yes it is disorganized, it is a forum. I don't recommend starting here, get a book, Vance Dickasons loudspeaker cookbook for example, and learn all of the fundamentals, learn the glossary of words used in audio (there are actually websites dedicated to this) and then come back with specific questions and search for the answers first. I can almost guarantee any questions you might have have been asked and answered at least 3 times on this site alone.

-use for home theater and stereo listening
Same requirement as far as I am concerned, although the HT sub needs to go down ~20Hz whereas the music sub rarely needs to, and f3 of 30-40Hz should do for most music. But my opinion, if you are willing to sacrifice space, get a big woofer and get music quality bass that extends down to where you want it to.

-powering an 18x30 foot room enclosed by 3 walls
Could you elaborate on this, is the missing fourth wall behind you or behind the speakers, what are the dimensions of this space? (dining room/kitchen/halfwall?)

-cabinet size can be reasonably large but would perfer a box design rather than tubular
I haven't built it yet but I've modeled a subwoofer using two Dayton 18" Classics in an isobaric configuration, see pics and winisd plots.

-performance down to 20hz, I will also be adding bass shakers to the couch for low freq's.
If you want the smaller box, I would recommend the 2.5ft^3, with either a LT (Linkwitz Transform) or an Eq, I have the Behringer DEQ2496 and a 15" IB woofer in a U-frame dipole and the bass rolloff is quite similar to the 2.5 ft^3 model, it eq's +- 0.5dB on 1/3 octave resolution.


-build cost $500-800 drivers and amp
Dayton 18" x2 ~$200
An amp like the Behringer EP1500 or 2500 $300- $350 respectively (never owned one but plan on buying them based on user reviews)
Behringer DEQ2496 $300

All available from parts express

[nunayafb]

The CAD model:

[twowheeled]

Originally posted by nunayafb
Yes it is disorganized, it is a forum. I don't recommend starting here, get a book, Vance Dickasons loudspeaker cookbook for example, and learn all of the fundamentals, learn the glossary of words used in audio (there are actually websites dedicated to this) and then come back with specific questions and search for the answers first. I can almost guarantee any questions you might have have been asked and answered at least 3 times on this site alone.

-use for home theater and stereo listening
Same requirement as far as I am concerned, although the HT sub needs to go down ~20Hz whereas the music sub rarely needs to, and f3 of 30-40Hz should do for most music. But my opinion, if you are willing to sacrifice space, get a big woofer and get music quality bass that extends down to where you want it to.

-powering an 18x30 foot room enclosed by 3 walls
Could you elaborate on this, is the missing fourth wall behind you or behind the speakers, what are the dimensions of this space? (dining room/kitchen/halfwall?)

-cabinet size can be reasonably large but would perfer a box design rather than tubular
I haven't built it yet but I've modeled a subwoofer using two Dayton 18" Classics in an isobaric configuration, see pics and winisd plots.

-performance down to 20hz, I will also be adding bass shakers to the couch for low freq's.
If you want the smaller box, I would recommend the 2.5ft^3, with either a LT (Linkwitz Transform) or an Eq, I have the Behringer DEQ2496 and a 15" IB woofer in a U-frame dipole and the bass rolloff is quite similar to the 2.5 ft^3 model, it eq's +- 0.5dB on 1/3 octave resolution.


-build cost $500-800 drivers and amp
Dayton 18" x2 ~$200
An amp like the Behringer EP1500 or 2500 $300- $350 respectively (never owned one but plan on buying them based on user reviews)
Behringer DEQ2496 $300

All available from parts express

I have read up on loudspeaker design and do have a book on it. However I am not looking to reinvent the wheel or so to speak, I would perfer to copy a well known and proven design rather than build it from the ground up. What looks good on paper doesn't always sound good when built, which is why I don't want to take my chances selecting a driver and designing my own enclosure for it.

The missing wall is a side wall to the right of the listener, it opens up to the rest of the the basement. Opening would be about 18 length by 10 foot ceiling. Box size is a non-issue I don't mind having a large cabinet.

Is there no sort of listing for catagorized common builds? Sorted by driver size, enclosure design or cost?

[2100]

Since you are not aiming to reinvent the wheel (eg try horns, pro audio drivers etc) and home theatre is the equation, my best solution to offer is try the SVS PB12+/2 and PB12+. Very competitively priced that you don't really save much by DIY. Premium veneers too. It has loads of SPL for home theatre, and since you are trying out DIY, the multiple tuning options by vent plugging would please your fingers.

http://www.svsound.com/products-sub-box-plus1.cfm

http://www.svsound.com/products-sub-box-plus2.cfm

I guess you are in Canada, so shipping is low.

[owdi]

What are your woodworking skills? If you are just looking for a good value, it's hard to beat the kits at Parts Express.

Dayton T1503 15" Titanic Mk III Subwoofer Kit
http://www.partsexpress.com/pe/showd...number=300-764

The parametric eq should let you tune the low end to taste. With a 15" woofer and 20mm of one way throw, you don't need a ported box.

Don't know if they ship to Canada though.

Dan

[twowheeled]

Originally posted by owdi
What are your woodworking skills? If you are just looking for a good value, it's hard to beat the kits at Parts Express.

Dayton T1503 15" Titanic Mk III Subwoofer Kit
http://www.partsexpress.com/pe/showd...number=300-764

The parametric eq should let you tune the low end to taste. With a 15" woofer and 20mm of one way throw, you don't need a ported box.

Don't know if they ship to Canada though.

Dan

I consider myself pretty good at woodworking, so complexity of the enclosure doesn't really concern me.

[simon5]

First you need to know the parts suppliers for subwoofers...

In canada :
http://www.creativesound.ca/

In USA :
http://www.partsexpress.com/
http://www.acoustic-visions.com/
http://www.aespeakers.com/

There are many others but those are my favorites.

Then you need to read this WHOLE website... DIY Subwoofer page :
http://www.diysubwoofers.org/

After that, you'll have alot of knowledge and you will know better what do you want and we will be able to help you better.

Here is some software that can help you design better subwoofers :

WinISD Pro :
http://www.linearteam.dk/default.aspx?pageid=winisdpro

UniBox : (need Microsoft Excel since it's a Excel program)
http://home20.inet.tele.dk/kou/ubmodel.html

HornResp : (primary for bass horns and horns in general but can be used for everything, very powerful)
http://mywebsite.bigpond.com/dmcbean/

SubSim :
http://www.geocities.com/f4ier/newsubsim.htm

My personal recommandation for a first serious subwoofer since you are good at woodworking and you already built one would be a big box with passive radiators since your budget is high enough.

Cost would be : (from creativesound.ca in $CDN)
SDX 15" subwoofer driver for 239$
LT1300 ED 1300 watts plate amplifier for 389$
2x PR1821 18" passive radiator at 139$ each so 278$
Total : 925$ (Yeah I exaggerate, like always!)

Then a 4' x 8' sheet of 3/4" baltic birch plywood ~75$
Glue ~10$
Wires ~5$
Paint ~20$
Weatherstripping double sided tape
Etc.

Anyway, that's my personal opinion, but that subwoofer would be awesome.

Good luck !

[simon5]

I also saw that you don't want to reinvent the wheel...

Then you could use whatever Creative Sound Solutions, or Acoustic Elegance, or PartsExpress, or Acoustic Visions recommends for the drivers they are selling.

Some of them will even give you plans. My first subwoofer was made following a Adire Audio plan, it was very well done. I guess you could use it with another driver since they don't sell subwoofers anymore but it's their plans so maybe there would be a copyright issue.

[owdi]

simon5 - nothing personal, but I really don't like your recommendation to use passive radiators. You could get superior performance by dropping the PRs, buying two drivers, and going sealed. Arrange the drivers in a push-pull configuration, keep the box the same size, and use the bass boost built into the amp to fill in the low end.

This gets you lower distortion, group delay and price. You loose some efficiency around the tuning frequency, but gain it everywhere else. Overall power handling goes up too.

Dan