Proven sub designs

**cynical2** · **11-23-07, 08:53 AM**

Greetings, speaker geniuses!

I don't know anything about designing speakers, but am pretty handy with woodworking...and, like everyone else, I'm always interested in getting the most value for my $$$ on anything I buy.

So, I'm toying with the idea of building a sub and/or speakers for my HT.

I'd like to simply reapply a proven design (again, since I know nothing about speaker design).

My question: Is there a place that has a "library" of DIY speaker designs? Ideally, I'm looking for a list of known builds, with the design details (with enough information to allow me to execute the build myself), expected results (frequency response, etc), and a list of materials needed for that build. An idea of cost for the respective design would also be helpful.

TIA for any help!

**BoomieMCT** · **11-23-07, 10:40 AM**

There are several. Here are some;

Parts Express Project Showcase
Zaph Audio
DIY Loudspeaker Projects
DIY Audio projects
Speakerplans
Single Driver Speakers DIY

There are lots more, this is just a quick sampling. Many driver manufacturers also give designs on enclosures for their products. Also, most forums have info on builds as well.

**Warpdrv** · **11-23-07, 02:28 PM**

I think that as far as sub woofers are concerned, you may well find everything you need right here in a ported sub, possibly a LLT design... unless i'm reading your post wrong and your looking to try a more extravagant enclosure design...

**cynical2** · **11-23-07, 06:25 PM**

Thanks, guys. Definitely will read through the links. I'm just at the "thinking about it" stage at this point, and trying to understand what's out there and makes the most sense for me.

In my dedicated HT, I've got Klipsch 4.2 mains and a Klipsch center. Surrounds are inexpensive in-walls (that sound fine for their purpose). No sub.

Receiver is an Onkyo SR605.

I'd like to find a sub design would be as inexpensive as possible while delivering...

(1) Adequate (low enough) frequency response at "normal" movie listening levels...not so worried about being able for the neighbors to hear me, or for that matter having it shake me out of my seat. I probably need some help understanding what is "low enough" for a Home Theater application...20Hz? 15Hz? 12Hz? I've seen various opinions on this, and I'm not sure (practically speaking) what's adequate.

(2) To answer one of the questions asked...definitely not looking for an extravagant design. I'm a "function over form" kind of guy. The simpler, the better.

(3) The simpler to build, the better. After all, if I end up doing this, it will be the 1st time. Don't want to bite off more than I can chew...

Any specific sub design recommendations are also welcome, as well as recos on how to best drive the sub...

Thanks again.

**ccdoggy** · **11-23-07, 07:13 PM**

I think the biggest question is if you can accomidate a LLT sub. they are very popular and in my opinion produces the most output, clarity, and dynamic out of just about any design i have heard. It also is usually cheapest in output vs $.

Its also easy enough to make, mine is just a big box with interior supports, with a 6" port out the top of it. some go the Sonosub route and thats supposidly "better" due to the cyndrical shape but i like mine just the way it is.

for about $800 i built my FI car audio Q 15" sub, in a 12 cuft box powered by a EP 2500. I am only using half the power of the amp so i can add another one later if needed.

**BoomieMCT** · **11-23-07, 08:22 PM**

This is a very open ended question. Let's start with three questions; What size room do you have? Is it sealed? What is your total budget (for a sub)?

**Warpdrv** · **11-23-07, 08:59 PM**

Also, how much room do you feel you can accomodate to a subs footprint... getting into a LLT design usually means a good amount of room for a box, but a cylindrical design takes up less realestate but is quite tall....

**cynical2** · **11-23-07, 10:43 PM**

Room is 18'x15'x8' ceiling...basement room. No windows. One double door (regular hollow core bedroom type door...48" wide with "normal" installation) that is closed during movie time...

Drop ceiling.

The one exterior wall is insulated. The other 3 walls are internal to the house and back up to other areas of the basement, and are not insulated.

No treatments...

To be clear, I'm far from an "audiophile" and am not really striving for that level of perfection. We only use the room for movies/satellite...no music...so perfect accuracy also isn't as big of a concern. This is a theater for my wife and two pre-teen kids...and lots of friends of the kids (seem they have taken quite the liking to the new HT).

As far as where I could put it...the two most convenient locations would be (1) right under the center of the screen...a long open area is there now. It could be 2x2x??? as long as the ??? dimension can be along the screen wall, laying under the screen (may not be possible acoustically?), or (2) standing in a rear corner...could be a tube that's up to 18-20" in diameter.

Regarding budget...I haven't set one primarily because I don't understand the technology/choices well enough, and a setting a budget at this point would be entirely arbitrary. I'd like to spend the least I can, while getting a sub that will add significantly to my current setup. But, as I said, I don't need audiophile performance...I just want to make the theater "come to life". I know I'm missing a lot on the low end now, as my Klipsch mains are -3db at 36Hz. So, I'm looking for that "sweet spot", where I can get a lot of value for my $$ without going overboard (in both cost and the pursuit of more performance than I really need).

Hopefully, you guys can give some insight on how much my budget should be given my description of what I'd like to accomplish. I'll be able to live with whatever the cost is...but, the more it costs, the longer it will take me to save enough $$ to start the project.

**avaserfi** · **11-23-07, 10:52 PM**

While this might not be the exact idea you are looking for I would recommend looking into getting four of these this subs placed in each corner of your room if possible. This simple, inexpensive, solution will likely be better than most any single sub. Using four of these subwoofers will give you great output with inaudible distortion and will add in quiet a bit of self-treatment because of the nature of having four woofer interacting together.

Just another inexpensive easy option that will likely be better than building a single great subwoofer.

**BoomieMCT** · **11-23-07, 11:10 PM**

I asked the size of the room (and whether it was sealed or not) just to get an idea of how big of a sub might be needed, and what type of enclosure would work best. With a sealed 2200 cubic foot room you should have a decent amount of room gain to boost your low end. I have a similar configuration to my HT and two sealed 12" subs (in my case Titanic III's) work very well for me. A single 15" LLT sub should also work pretty well and would probably be a bit cheaper. It sounds like your free corner would be great to stick a sonosub into. For how to make an enclosure sonosub.exe should be a big help.

I asked about you budget not to try to push an "audiophile" solution, but rather to give a better idea for suggesting designs. If you go with a sonosub the enclosure will run you about $70 for the sonotube, $25 for some MDF, $10 for the carpeting and $20 for miscellanious materials (screws, spray glue, dowels, paint, etc.). So you are looking at $125 for a good sized enclosure before buying an amp or driver.

On the cheap (but still good) side something like a Dayton 15' DVC or Dayton Reference 15" HF would probably work well. Both are proven performers and are relatively inexpensive ($137 and $150). I'm not sure if there is anything as good for the same price (maybe someone can fill me in).

For power a Oaudio500 watt BASH amp ($230) or Dayton 500 watt HPSA amp ($240) would work. Both have some PEQ capability that can be very useful. Or you can use a good rack mounted amp - lots can be found on Craigslist or ebay.

So all-in-all you're looking at $600 give or take. There are cheaper options and more expensive ones as well. IMHO something like I described should match your system well.

**cynical2** · **11-23-07, 11:30 PM**

Quote:

BoomieMCT wrote:

I asked the size of the room (and whether it was sealed or not) just to get an idea of how big of a sub might be needed, and what type of enclosure would work best. With a sealed 2200 cubic foot room you should have a decent amount of room gain to boost your low end. I have a similar configuration to my HT and two sealed 12" subs (in my case Titanic III's) work very well for me. A single 15" LLT sub should also work pretty well and would probably be a bit cheaper. It sounds like your free corner would be great to stick a sonosub into. For how to make an enclosure sonosub.exe should be a big help.

I asked about you budget not to try to push an "audiophile" solution, but rather to give a better idea for suggesting designs. If you go with a sonosub the enclosure will run you about $70 for the sonotube, $25 for some MDF, $10 for the carpeting and $20 for miscellanious materials (screws, spray glue, dowels, paint, etc.). So you are looking at $125 for a good sized enclosure before buying an amp or driver.

On the cheap (but still good) side something like a Dayton 15' DVC or Dayton Reference 15" HF would probably work well. Both are proven performers and are relatively inexpensive ($137 and $150). I'm not sure if there is anything as good for the same price (maybe someone can fill me in).

For power a Oaudio500 watt BASH amp ($230) or Dayton 500 watt HPSA amp ($240) would work. Both have some PEQ capability that can be very useful. Or you can use a good rack mounted amp - lots can be found on Craigslist or ebay.

So all-in-all you're looking at $600 give or take. There are cheaper options and more expensive ones as well. IMHO something like I described should match your system well.

Thanks, Boom. Lots of great info!

I didn't take your question about budget that way (that you were pushing an "audiophile" solution)...budget is a very real constraint and definitely needs to be considered. Unfortunately, I just don't have a good answer for it. Some of the designs/builds I see just blow me away, and I just didn't want anyone to think that I was after the "king of all subs".

Your info helps me understand from the standpoint of how much $$$ this will cost, once all is said and done.

What are people's thoughts about going with multiple small subs, per avaserfi's suggestion (thanks for bringing it up...I thought about 2 subs, if needed...but hadn't even considered 4)? My intuition tells me that the bass as I move around the room would be all over the place (that in some places there'd be constructive interference between the 4 subs, and other places destructive)...but that intuition is based on very little real knowledge of subwoofer interactions. Is that also an idea worth serious consideration?

**avaserfi** · **11-23-07, 11:40 PM**

Quote:

cynical2 wrote:

What are people's thoughts about going with multiple small subs, per avaserfi's suggestion (thanks for bringing it up...I thought about 2 subs, if needed...but hadn't even considered 4)? My intuition tells me that the bass as I move around the room would be all over the place (that in some places there'd be constructive interference between the 4 subs, and other places destructive)...but that intuition is based on very little real knowledge of subwoofer interactions. Is that also an idea worth serious consideration?

Having one single sub in a room causes uneven room response as well but the addition of another helps this problem (assuming proper phase/gain/crossover settings). The addition of 2 more subs making a total of four not only increases output but again with proper settings you can have an extremely even low end response throughout the room. As with any multiple subwoofer setup you run the risk of destructive/constructive wave interaction, but with proper setup this need not be a large concern.

The previously mentioned subs were suggested due to their low distortion and linear response coupled with their ultra low price.

**cynical2** · **11-23-07, 11:43 PM**

Quote:

avaserfi wrote:

Having one single sub in a room causes uneven room response as well but the addition of another helps this problem (assuming proper phase/gain/crossover settings). The addition of 2 more subs making a total of four not only increases output but again with proper settings you can have an extremely even low end response throughout the room. As with any multiple subwoofer setup you run the risk of destructive/constructive wave interaction, but with proper setup this need not be a large concern.

The previously mentioned subs were suggested due to their low distortion and linear response coupled with their ultra low price.

Cool stuff...thanks for the info! I actually have 4 places that I could put small-ish subs, so it would be an option physically.

**thxgoon** · **11-24-07, 12:41 AM**

You sound like a perfect candidate for a smaller LLT sub design. You're not looking for reference output but are looking for the extra sub 36hz info. Read Steve's LLT Explained thread at the top of the DIY sub forum, you will love the extension and if form over function is your method you could definitely get away pretty inexpensively. An EP2500 is about $300 and a good 15" driver is around $175 or so. You could have a sweet 15" LLT for around $500. One big sub will have more output and extension than 4 smaller subs placed in different places.

**Warpdrv** · **11-24-07, 08:36 AM**

I would say that 2 subs would be more then adequate in that room... possibly dual 15" LLT powered by a single EP2500 for easily less then $1K... Probably more then you will ever need, and never have to upgrade...

**brent_s** · **11-24-07, 09:23 AM**

My current sub is a DVC15 in 5.9 ft^3 net, tuned to 17hz. Dedicated theater room is 24x16x9, so a little larger than yours. With corner placement, it measures flat to 10hz with 100dB sweeps using REW. It'll play louder, that's just the maximum output sweep I've run. I very seldom do, but it's capable of doing THX reference level at the seats without any signs of strain. It's fair to note that I'm sitting relatively nearfield with about 7' to the sub.

Simplicity to build? Home Depot carries .75x16x48 MDF shelving for $5/each. Five of those and you can easily build a 16x17.5x49.5 enclosure. Only cutting required is cutting two 16x17.5 pieces from the fifth panel to make the top and bottom. The rest of that panel can be used to make bracing. FWIW, that 48" dimension is more like 48.75.

The cabinet could just as easily be a suitably sized sonotube.

Throw in a 4" Precision Port and amp of your choice and you're done. Paint to taste.

-Brent

**BoomieMCT** · **11-24-07, 09:49 AM**

Quote:

cynical2 wrote:

Thanks, Boom. Lots of great info!
What are people's thoughts about going with multiple small subs, per avaserfi's suggestion (thanks for bringing it up...I thought about 2 subs, if needed...but hadn't even considered 4)? My intuition tells me that the bass as I move around the room would be all over the place (that in some places there'd be constructive interference between the 4 subs, and other places destructive)...but that intuition is based on very little real knowledge of subwoofer interactions. Is that also an idea worth serious consideration?

This is a sort of controversial topic so you'll probably get a range on answers. IMHO If properly set up multiple subs can give you a larger sweet spot in the room. I was able to get much better bass with my two subs than with a single corner mounted sub. However If improperly setup they can give you much less even bass and possibly less bass overall as one sub can cancel out another. I'd recommend multiple subs if you have the room to move them around the HT and if you have to patience to set them up right. It is not a trivial thing to do and I wouldn't even attempt it unless you have RoomEQ wizard and a decent mike.

There are some threads in this forum about setting up mutiple subs. I'd do a search and check those out.

**Warpdrv** · **11-24-07, 09:55 AM**

I agree... dual subs smoothed out the bass in my room so nicely, I would never go back to a single sub... I had no idea how much better a second sub would improve my setup. My room is much larger and oddly shaped open to other large rooms (8200 cu.ft.) and not a sealed rectangle, which can be more problematic.

Excellent example btw brent... nice looking sub there...
Seems far cheaper to build then a sonosub...

**thxgoon** · **11-24-07, 11:49 AM**

Ya dual subs will even response for multiple listening positions. I built 2 subs for this very purpose. A common misconception though is that 4 subs will sound 4 times better than one in all respects. What is closer to the truth is that the 4 subs will have no more extention and not much more output than a single sub, with the exception of where room placement will play in favor. Here it sounds like he is looking for extention under 36hz. That is already pretty low and it should be pretty easy to load multiple seating positions with 1 sub for that narrow band. But two would definitely be a bonus. Was there ever a budget mentioned? For $1k you could build something that would qualify you in every category but if your budget is half of that, IMO a single larger sub with a BFD would be a better solution.

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