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Discussion Starter #1 (Edited)
Hello,

I'm looking to build a subwoofer that can rumble for movies but also handle music fairly well. I listen to pretty much all types of music. The only size restriction I have is that I would like to be able to fit it inside of my truck bed with a tonneua cover over it. This limits me to about 18" x 48" x 60" on the absolute max. I don't really know what I want in terms of SPL levels because I've never had a real sub before. I just know I want something that can help my bookshelf speakers during music and also provide the rumble during action movies.

Budget is around 500 USD.

I've been looking at the Dayton Reference series subs and am still confused about the difference (in terms of how I would design an enclosure) between the HF and HO for both the 12 and 15 and I've recently discovered the Dayton Ultimax line and those seem as though they could be a good fit in a ported enclosure.

For amps I was looking at either a bash 300W plate amp or the Behringer NU1000DSP. The idea of having the DSP seems very helpful and the size of it doesn't really matter for me as I have a full size truck to move all of this around.

I either need high level inputs on my amp like the bash plate amp or the ability to accept from RCA connection as my current home theater amp does not have sub level output.

I'm also lost on what "tuning" a box means and how I discern the tuned frequency of a box I am designing.

Thank you in advance
 

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Welcome to HTS!

Dayton makes great stuff; I don't think you'll go wrong there. Something to keep in mind are your other speakers. A lot of a larger sub's potential can sit unused if the main speakers can't produce enough output.

How big is your room? That will help you decide whether to do a sealed or ported box (big room, go ported - I have two sealed 18s and they run out of steam in my basement; I'd love to build a couple dual 18 ported enclosures)

If you're looking to build on your own, awesome, there are TONS of great builds out there - the sky's the limit. But if you don't want to make sawdust and worry about fit, you can get pre-cut "flat-packs" from places like diysoundgroup - for example, the link here is for a Dayton 12 (http://www.diysoundgroup.com/sealed-subwoofer-flatpacks/2-sub-flat-pack.html).

There are so many more experienced members here that will chime in, but you will have your mind blown with good bass (and you'll just want more...).

Look up the Marty Sub - I helped a friend build two MartyCubes with Stereo Integrity HT18s and WOW those things sound great!
 

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"Or the ability to accept RCA connections as I don't have sub level out"? What does that mean? What receiver do you have?

Sent from my XT1575 using Tapatalk
 

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Why does it need to be able to fit in your truck? This is for a mobile setup? Or just prepared to move to your next residence? Is your current home theater unit an HTIB unit with a passive sub? Like was asked, what do you have now? How complicated a build are you willing to do? You want to try a folded horn type? Maybe want to take a look at BFM's various build plans?
 

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Discussion Starter #5 (Edited)
I'm currently a college student who has to move too and from home and school during the summer so I need to be able to transfer this around. I'm not sure how feasible this is but I was hoping to build this sub as something to grow into more next summer when I either build my own front mains or buy some. For now I have speakers from goodwill/garage sales to use as mains and I would hope I can turn this sub down enough to balance with whatever speakers I have. I currently have an old preamp, power amp combo made by Kenwood that I use to power two smaller bookshelf speakers in my room at 125 WPC. I also have at home two old large Jensen 3120 which are three way mains. I plan to use the Jensens in my house next year at school along with this sub for movies/music during parties with friends. The sub is certainly something I plan to grow into more and I am always on the lookout for a better receiver/mains setup.

Right now I am modeling a system using the Dayton Ultimax 15 in a 7ft^3 box with a 2x13in 30.28in long rectangular port in it which I believe tunes me to 17hz with peak port air velocity at 17hz being about 20m/s. The issue with this setup is that I get cone excursion of 22mm at 27hz. I believe I've seen people saying that this ultimax can take it but I'm not sure. I'm still figuring out how this setup would lay out on wood and overall dimensions using Nx (CAD program provided by my university). This is with 800 W system input power and a third order butterworth highpass filter at 17hz which I found from someone else's dayton 15" ultimax build. They did there build in a 10 cubic foot box which I hope I can shrink down to 7 as to get it to fit in my truck much more easily.

Is this current setup at all feasible? Sorry if I'm way off in left field or asking for things that aren't reasonable I've read through a lot of posts on here and I am getting mildly overwhelmed and really just looking for something that will work, sound good and allow me to grow into it.

Also I am capable of building any type of build as long as it can handle music and hopefully still rumble for movies and fit in my truck bed and costs near 500$ including wood.
 

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Discussion Starter #6
So I have a new design and this time I'm providing all the information I can because I think this may be my final assuming it will work.

So this design is a heavy modification of the marty cube. The entire project will be made from .75" MDF unless otherwise specified. I have 2 ports that are 1" x 14.56" and that are 35.48" deep. The overall dimensions are 18"x24"x42". I have 4 support beams running across that are going to be 1" dowel rods. The ports are right along the wall of the enclosure so I will be mounting those to the walls which I believe should make this thing very stiff overall. The front panel is going to be two pieces of .75" MDF glued together to allow me to recess/flush mount the subwoofer.
Attached are an image of my mockup in CAD along with Cone Excursion, port velocity and cone excursion. I have included the project from winISD aswell which is a modification of one posted by Mike P. in another 15" Ultimax thread.

So my question for you all is what do you think of this design, will it be a sub capable of music and also capable as a beast of a home theater sub?

Thank you all in advance for your input
 

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The back, top, and bottom of the enclosure will need bracing, not just side to side, and the outer port walls will need bracing (the inside of the ports is braced with the doweling, but the outer walls of the ports are not) - they will flex! My sealed 18s are made with 1" mdf, but I don't think there's internal bracing, because the walls do flex noticeably - I can't set stuff on top of them. Very nice having NX at your disposal! I love that system.
 

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Discussion Starter #8 (Edited)
Re: 12"/15" Subwoofer for 50% music 20% movies and 30% gaming

The ports will be mated right to the outside walls of the overall structure, so there is only a 1 inch gap there. Do I really need bracing in there? I will add vertical bracing later tonight when I should have more time to work on the model. Do you think that this design overall will be sonically pleasing for both movies and music? I'm not overly familiar with all the readouts from winISD and was hoping someone could provide some feedback on that. The dual port design should be functional right?

Do I need any sort of foam to line the inside of the box with? I'm going to be caulking the seals so that they're air tight, is that needed? Anything else I'm forgetting? Recall that I'm fairly new to this hobby and go ahead and tell me something is bad if it's bad or should be done differently I'm here to learn instead of just blindly going into this project.

Thanks for the feedback so far
 

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Your airspeed is below 18 m/s, so you're good on that. The 1" gap doesn't keep that outside face from flexing - remember, the port will have air oscillating rapidly in it, so a resonant frequency will be induced at some point on the spectrum (meaning at some freq you may hear something obnoxious). The Marty Sub has bracing subdividing the port for that reason. I think you'll be fine with your excursion - 800 rms is a lot, and what amp are you using? Your 17 Hz filter may be superseded by the highpass filter in most amps.

Don't worry about music vs movies - if it can handle movies well it will handle music well.

Foam is a preference thing from everything I've ever learned about subs - you can try some of that eggcrate foam, or poly-fil from pillows, etc. but lots of builds I've seen don't use anything. I'm assuming by your comment about using NX that you're in school for some type of STEM program; therefore, experiment!

Definitely caulk. How will you be mounting the driver? You can go all pretty and use hex head screws and inserts, but honestly if I were building right now I'd just glue some hardwood blocks behind the mdf to screw a deck screw into.
 

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Discussion Starter #10
Your airspeed is below 18 m/s, so you're good on that. The 1" gap doesn't keep that outside face from flexing - remember, the port will have air oscillating rapidly in it, so a resonant frequency will be induced at some point on the spectrum (meaning at some freq you may hear something obnoxious). The Marty Sub has bracing subdividing the port for that reason. I think you'll be fine with your excursion - 800 rms is a lot, and what amp are you using? Your 17 Hz filter may be superseded by the highpass filter in most amps.

Don't worry about music vs movies - if it can handle movies well it will handle music well.

Foam is a preference thing from everything I've ever learned about subs - you can try some of that eggcrate foam, or poly-fil from pillows, etc. but lots of builds I've seen don't use anything. I'm assuming by your comment about using NX that you're in school for some type of STEM program; therefore, experiment!

Definitely caulk. How will you be mounting the driver? You can go all pretty and use hex head screws and inserts, but honestly if I were building right now I'd just glue some hardwood blocks behind the mdf to screw a deck screw into.
The outer port wall is going to be double thick right now if you can wrap your head around that. I've attached a screenshot that hopefully can clear that up. Do you think that would be strong enough to not flex?

I am planning on using the Behringer iNuke NU1000 with DSP for my amp in bridged mode. This is shown to deliver 1000 watts into 4 ohms but I've recently read that Behringer's number is fairly over estimated. As for the 17hz tuning I have read that you can change Behringer's 20hz high pass down to 17hz but have not looked into the exact details.

Mounting the driver I'd like to use threaded inserts with black headed hexs for the looks as I plan on doing a nice glossy black finish on the box. Also on the note of mounting the driver I just saw pictures where a guy took and has supports running lengthwise to support behind each screw he is using to mount the driver, do you think that this is needed in my design?

I can certainly try different fills after getting the sub up and running.

Thanks again
 

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Gotcha on the double thick. That should be good. I know just the build you're talking about - the baniels one, right? I would take any of his builds as prime examples; some beautiful work (though you definitely don't need that much supporting with the double thick baffle). When you get to adjusting the filters on the iNuke, you'll find it's pretty straightforward. Download the amp software from Behringer and play around with it. There are a few tutorials out there on adjusting to get the lower highpass.
 

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Discussion Starter #12 (Edited)
Gotcha on the double thick. That should be good. I know just the build you're talking about - the baniels one, right? I would take any of his builds as prime examples; some beautiful work (though you definitely don't need that much supporting with the double thick baffle). When you get to adjusting the filters on the iNuke, you'll find it's pretty straightforward. Download the amp software from Behringer and play around with it. There are a few tutorials out there on adjusting to get the lower highpass.
Thank you so much for your guidance, I'll be doing this build in a few weeks after I'm done with classes. Planned it out now to order parts so I can have everything available day one.

I just had a good point mentioned to me, this is going to be in a college house, do you think I could get away with putting a sheet of plexiglass on top of the sub to catch spills or would this vibrate too much even at low volumes to be useful as a table? I can't imagine this thing vibrating too much seeing as to how it is going to weigh about 200lbs when done.

Got another question too, what do you suggest in terms of subwoofer feet for a 200lb box? Cheaper the better
 

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If it's well-braced it could definitely be used as a table. Plexi's not a bad idea to protect it. I've seen quite a few end table subs that you'd never know were subs, but bracing really is the key to an inert enclosure (not only good for putting drinks on but keeping all the energy as sound and not vibration). It's really remarkable how much panel movement those drivers can cause.
 

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Discussion Starter #14
I just want to thank you again for all your guidance in my endeavor to construct and plan this build. Keep a look out for build photos in early may.
 

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One other note... if you're gonna be transporting this beast to/from your university accommodations, put in some handles. Maybe figure out a way to get some wheels on the back end. This thing is going to be pretty heavy when it's all finished and you won't have any fun at all getting into and out of the bed of a pickup truck if it's all smooth surfaces and pretty rounded corners. Also, if there are stairs involved on either end of that journey, your friends will hate you unless you come up with a way to make it less horrible to move.
 

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Discussion Starter #16
How important do you guys think having the ability to remove the bottom cover of the whole enclosure is? My father is suggesting that I make it so that I can remove the bottom panel in case I ever need to access anything inside. I know I can reach through the hole after removing the sub driver but since my enclosure is so long I would more than likely not be able to reach the back. Do you think that I should consider this in my design?

I also will be spending some time figuring out a method for moving this behemoth around now that you mention it, possibly having removable casters on the bottom plate. I worry that a handle on this would be an eyesore because I cannot figure out a way to have them easily removable that will not mar the finish.
 

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I wouldn't worry about a removable panel - the only things inside are insulation (if you add that), wires, and binding posts. Just put your binding posts closer to the driver hole, and there won't be anything out of reach. As for sealing, just make sure you caulk every seam and you're good.

Less eyesore-ish could be wheels and handles for musicians'-type equipment (they sell them on Parts Express, handles, wheels). They're recessed, strong, and generally look pretty nice... they're also kind of expensive. If you really are planning on moving this thing around all the time and want it to last you may want to consider stuff like that.

Also, gloss finish is going to get trashed in a hurry - you may want to look into bedliner material like Duratex. It actually looks really nice and is very durable (obviously, since it goes in truck beds!)
 

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I wouldn't worry about a removable panel - the only things inside are insulation (if you add that), wires, and binding posts. Just put your binding posts closer to the driver hole, and there won't be anything out of reach. As for sealing, just make sure you caulk every seam and you're good.

Less eyesore-ish could be wheels and handles for musicians'-type equipment (they sell them on Parts Express, handles, wheels). They're recessed, strong, and generally look pretty nice... they're also kind of expensive. If you really are planning on moving this thing around all the time and want it to last you may want to consider stuff like that.

Also, gloss finish is going to get trashed in a hurry - you may want to look into bedliner material like Duratex. It actually looks really nice and is very durable (obviously, since it goes in truck beds!)
I would also avoid a removable panel, especially on a subwoofer. If you need to get in there, just pull the driver out. By having a removable panel, mostly what you do is introduce the possibility that it will get loose and start to rattle.

I started writing a reply with a link to recessed handles from PE, but apparently I was too slow.
 
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