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Dual 15" sealed beasts

post #1 of 32
Thread Starter 
Hey guys im thinking of trying to build a pair of 15" sealed subs powered by a Behringer EP2500. So far from what I understand on the very limited research I have done is this amp will give me 1,200 watts per sub. Basically I am trying to recreate dual drive hsu uls-15's or Rhythmic F15's. I would like it to be tuned as low as possible as this is for my home theater. I coms to you in search of resources to help me with this project. Such as, templates, 15" drivers for my purpose. Sub software? Can I buy a box prebuilt or would it be smarter to build my own box from scratch? I am good with handtools and can get a discount at Lowes but at this point I would have no idea how the insides work or how to even make my first cut. Thanks
post #2 of 32
Quote:
Originally Posted by Mpray1983 View Post
Hey guys im thinking of trying to build a pair of 15" sealed subs powered by a Behringer EP2500. So far from what I understand on the very limited research I have done is this amp will give me 1,200 watts per sub.
3rd party tested to put out ~800w/ch @ 2ohm @20hz with less than 1%THD. I would figure 8-900w/sub if they're 2ohm each. 650w/sub if 4ohm each.
Check the amp testing thread in the sticky at the top of the DIY forum.

Quote:
Originally Posted by Mpray1983 View Post
Basically I am trying to recreate dual drive hsu uls-15's or Rhythmic F15's. I would like it to be tuned as low as possible as this is for my home theater.
How you tune a sealed enclosure is with volume. The driver does the rest of the work. You can EQ it though and change the frequency response.

Quote:
Originally Posted by Mpray1983 View Post
I coms to you in search of resources to help me with this project. Such as, templates, 15" drivers for my purpose. Sub software? Can I buy a box prebuilt or would it be smarter to build my own box from scratch? I am good with handtools and can get a discount at Lowes but at this point I would have no idea how the insides work or how to even make my first cut. Thanks
Software: WinISD Pro
Box: you can buy one, build one, or have someone build one for you. That choice will be dependent on your needs and capabilities.
post #3 of 32
Thread Starter 
I have been playing with winisd for a few hours now and it really doesn't tell me anything. I'm looking for the plans on how to build the box and can find that anywhere.
post #4 of 32
Quote:
Originally Posted by Mpray1983 View Post

I'm looking for the plans on how to build the box and can find that anywhere.

Ck the master index on this forum.

http://www.avsforum.com/avs-vb/showthread.php?t=1104368

and ck here as well

http://www.hometheatershack.com/inde...wooferprojects

I used the two forums to get ideas about box sizes, drivers and amps. The people on this forum and the other forum listed are very knowledgeable.
post #5 of 32
What drivers are you using?
post #6 of 32
Browse through the master list of DIY Subwoofers already built.
http://www.avsforum.com/avs-vb/showthread.php?t=1104368

Though some links are still be functional, it will atleast give you an idea of what sealed sub you'd want to go with- matching driver, box size and power.
Depending on the driver, the box size could be as basic as a 22" cube.

There has been some great threads within the last week about 15" drivers and what application they work best in. With box size and modelling (Winsd) Qtc mentioned
eg http://www.avsforum.com/avs-vb/showthread.php?t=1341034

15" Drivers on the DIY'ers budget
http://www.parts-express.com/wizards...AT&srchCat=835

For starters, a really nice build
http://www.avsforum.com/avs-vb/showthread.php?t=1051665
post #7 of 32
Thread Starter 
Im interested in using the Dayton reference RSS390HF-4. I want to build two sealed boxes that can dig deep.
post #8 of 32
Quote:
Originally Posted by Mpray1983 View Post

Im interested in using the Dayton reference RSS390HF-4. I want to build two sealed boxes that can dig deep.

The HF is a great driver. Each sealed box will have to be atleast 4.5cuft to 6cuft.

What is your budget and room size?
post #9 of 32
Thread Starter 
My room size is 2500 cf but it has 3 large openings to a hallway and a kitchen. Right now I have a paradigm dsp-3400 which Im sure I could sell for $500. I was planning on a hsu uls-15 which is over $1000 then someone said to just build a couple since I would really like to have two subs. That was I get a larger amp and dual 15's for the same price. Dual uls-15 will get to 10hz when properly eq'd so that is the goal but I'm not holding my breath. I also really enjoy building things so the idea of making this myself seems like a great idea. I'm currently on winisd now and it won't give me box measurements which to me feels like it defeats the entire purpose of the program. All it does is show me a few graphs which to me don't mean anything until I can actually try the sub out in my room.
post #10 of 32
With the Dayton driver you're looking at 4.5cft is a perfect size. Making it bigger has very minimal effects.

I'm not sure when but I believe Kevin@DIYcable is bringing out the new Tempest drivers. Anyone have updated info on that?
post #11 of 32
Thread Starter 
I found someone else who did 21.75x21x21.75. Would those be a good
Measurements to start with? The 21" section...is that the depth, height or length? 2x4's for bracing and R13 for insulation unless anyone has a better idea. 2 pieces of 3/4 MDF for the front and top. I see the word baffle written alot but
Not sure what that is. Is it smarter to just use 2" cuts of MDF for the bracing rather than the 2x4's. Would it be better to use say 3/4 oak ply so I can stain/paint after more easily than use a veneer on top of MDF?
post #12 of 32
Thread Starter 
Winisd won't give you the box dimensions in the free version?
post #13 of 32
In the alpha version it won't. The beta version has recommended dimensions but the program itself isn't as good as the alpha version.

You can build it any dimension you want so long as the total volume is the same as what you modeled. Want a 1 cubic foot box...12"x12"x12". Want to change it up a bit 12"x10"x14.4". Still 1 cubic foot. Apply that to any enclosure size recommended.
post #14 of 32
Thread Starter 
These plans look relatively easy to follow...one thing i do not understand is the back pieces labeled port wall inner, middle and back. I have no idea if there is 3 of them and i have no idea if they are not touching. What is the purpose of that?
LL
LL
post #15 of 32
Here are a couple of links I found useful. Hopefully they will help you out a bit



http://www.hometheatershack.com/foru...me-calculator/

http://www.hometheatershack.com/foru...inisd-pro.html
post #16 of 32
when modeling in WinISD pro make sure to check out the excursion table, 90% of the time the excursion (xmax) of the sub will be the limiter on how much power the sub will take, not the power handling of the sub in home theater applications. Car audio is different since most music doesn't reach below 30hz. Case in point, the Dayton HF, its rated for 500wrms but in the recommended 4.5cf sealed box the excursion starts limiting power handling to below 500w around 35hz and drops off to ~250w around 20hz. I've seen a lot of people modeling boxes/amps without taking the cone excursion into account. Then they come back and ask "whats this strange noise my sub is making when I crank it up?" question.
post #17 of 32
post #18 of 32
so far, my 2 MFW-15s in 3cf boxes gave me flat down close to 10hz (mostly due to room gain).

http://www.avsforum.com/avs-vb/showthread.php?t=1334025
post #19 of 32
you might want to double the drivers and build something like this:

http://www.htguide.com/forum/showthr...0&page=1&pp=35
post #20 of 32
Thread Starter 
After taking a lot of your advice into consideration I have decided to go with two Dayton RSS390HO-4 in two separate sealed enclosures measuring 21"Hx20.5"Wx22"D. I decided on the HO over the HF due to box size for each. Since this is going in a living room in a condo it doesnt really matter and the smaller wont hurt me. Volume of this box is 110L accounting for the driver. The Vas is 109L. I think I managed to get this pretty damn close. I am going to build a mockup demo box out of MDF soon after the 4th and if it sounds better than my DSP-3400 then I will be sold on this and I will never buy another commercial sub again. I plan on making my two boxes out of furniture grade 3/4 inch birch or oak. If there a difference between the two?
post #21 of 32
Thread Starter 
Should I add polyfill or foam to the walls considering the box is right at manufacturers spec? Should I make the box 20% smaller and add polyfill?
post #22 of 32
What, no one is recommending the MFW15 driver? Can you do x4 90l enclosures (20x20x20)?
post #23 of 32
Two dual opposed boxes using four MFW-15's powered by an EP2500/4000. You could even power 4 dual opposed boxes and get some serious lfe. $77 per driver is hard to beat.

$300 for the amp.
$320 for 4 drivers or $640 for 8
$150 for EQ.
post #24 of 32
Thread Starter 
I found the 4 mfw-15's and will order them this week. Ordering all 4 will put a serious delay in my build overall. I plan on buying a EP4000 for the amp and an eq. I'm still looking for recomendations on the eq. Will dual opposed give me a noticeable difference over two separate single sealed enclosures? Or should I build one dual opposed and then wait a few weeks and build the 2nd enclosure? I'm planning on two 4.5cf enclosures. My fear is buying the two mfw-15's for one enclosure and when i order the 2nd pair they are all sold out. Thanks
post #25 of 32
Quote:
Originally Posted by Mpray1983 View Post

My fear is buying the two mfw-15's for one enclosure and when i order the 2nd pair they are all sold out. Thanks

From what I've learned last Monday there were about 145 total available at the two sources that I know, DIY Group and GR Research. I now have my 8
post #26 of 32
Quote:
Originally Posted by Mpray1983 View Post

I found the 4 mfw-15's and will order them this week. Ordering all 4 will put a serious delay in my build overall. I plan on buying a EP4000 for the amp and an eq. I'm still looking for recomendations on the eq. Will dual opposed give me a noticeable difference over two separate single sealed enclosures? Or should I build one dual opposed and then wait a few weeks and build the 2nd enclosure? I'm planning on two 4.5cf enclosures. My fear is buying the two mfw-15's for one enclosure and when i order the 2nd pair they are all sold out. Thanks

Go big or go home.

4 15" quality drivers for $440 shipped is a great deal. The EP4000 isn't going anywhere, the drivers are not going to last long.

Also, 2 15"s sealed subs are not beasts, but 4 15"s gets you closer to the beast nickname
post #27 of 32
Thread Starter 
Okay deal I'll order 4 on Friday
post #28 of 32
Quote:
Originally Posted by Mpray1983 View Post

Okay deal I'll order 4 on Friday

Good choice. I have four reserved that I will be buying soon. I thought about getting 8, but really don't have the room...
post #29 of 32
Quote:
Originally Posted by Mpray1983 View Post

I found the 4 mfw-15's and will order them this week. Ordering all 4 will put a serious delay in my build overall. I plan on buying a EP4000 for the amp and an eq. I'm still looking for recomendations on the eq. Will dual opposed give me a noticeable difference over two separate single sealed enclosures? Or should I build one dual opposed and then wait a few weeks and build the 2nd enclosure? I'm planning on two 4.5cf enclosures. My fear is buying the two mfw-15's for one enclosure and when i order the 2nd pair they are all sold out. Thanks


I would go a touch bigger on the boxes, 6cf dual opposed is just about Ideal IF you have good control over your power input, a ~10hz HPF, and the 2 fingers you use to turn the volume nob. 5cf dual opposed is perfect for 500w to each cube with not worried about over excursion down to 4hz.

with 3/4 material a 24" double baffled cube is just under 6cf with drivers and bracing and a 23" double baffled cubs it just over 5 ft with drivers and bracing.
post #30 of 32
Thread Starter 
The boxes are 5.29cf before accounting for driver volume and bracing. I plan on using long thin pieces for the bracing. I'm going to add 1 lb of polyfill per cf. I wish I could
Make them larger but at this point in my life I have about reached the maximum size for the allotted. 20w x 23.5d x 24h. These measurements, L & H match up perfectly with my tv stand and will help hide the boxes a little for WAF. Will the BFD1124 help me boost the low end properly?
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