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Discussion Starter #1
I can build subs, but I get hung up on the design and modelling phase.

With that said, I came into possession (2 long stories) of two new UM15-22 woofers and got a great deal on a new Behringer NX3000D to drive them.

I am trying to come up with a design that works well with the UM15, but it seems like it was sort of an "odd duck" for DIY subwoofers. Most say that it needs a box to be large to be effective, and thus the reason most people just jump to a UM18 instead (or other 18" driver).

That is fine, but I already have these two UM15s in my possession.

My two current subs in my theater are an older SVS 20-39 PCi (cylinder style sub) and a DIY clone that I made after someone modeled it up for me a couple of years back. They measure almost identical even though my "clone" DIY subwoofer isn't in a cylinder shape.

I have not yet decided if the new subs will flat out replace the two 12" subs that I already have, or be in addition to them long term. For the short term they will go behind my 2nd row of seats, and long term might end up behind my false screen wall.

Room is 14' x 24' x 8' so just under 2700 cuft.

Current subs are tuned with REW and a MiniDSP and work well, but like I said, I came into possession of these new UM15s for almost nothing (like really, almost nothing) and with potentially 900Watts from the amp per subwoofer (on paper anyway), I thought that this would make a good late summer/early fall project, but I need to get my design sorted out.

I was looking at one of the Marty style. I know that the UM15 claims that it needs 11cuft to really hit optimal specs, but if these go behind my seating, they might not pass the "wife test" being that big, but at the same time, if I need to "hide them" behind the screen wall to make them really perform, then I might be open to doing that sooner rather than waiting until later.

The main reason that I wouldn't just put the new larger 15" subs up front is that it would mean either putting the two mis-matched looking 12" subwoofers in the room somewhere (again, doesn't look great) or getting rid of the current two 12s completely.

So thoughts on a box design/size that would a good one for the UM15-22 woofers? Thanks all.
 

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Discussion Starter #2
As I said, I am terrible at modeling, but I've been trying.

In WinISD, I modeled the following:
Full 18" Marty sub flat pack from GSG, but with a cutout for a 15" woofer
Mini 18" Marty sub flat pack from GSG, but again with a cutout for a 15" woofer
Marty 15 sub flat pack from GSG
Kuda 15 sub flat pack from DIYSG
Parts Express' 3cuft SEALED flat pack (just as a reference of what a number of people seem to have done. I don't want to go sealed.)

The Full 18" Marty seems the "winner," but I'm not sure how much "better" it is over the Mini 18" Marty that is 8" shorter (and easier to get wife approval, or at least fewer wife complaints. LOL)

Any thoughts from people?

Again power will come from a NX3000D (rated at 900 watts per channel at 4 ohms, but heard this is closer to 600 watts in reality.)

Thanks.
 

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This is what I came up with using "Speaker Box Lite" app on my phone. With a 6.5cuft net enclosure and a 18hz port tuning you'll have a -3db point of about 21hz. Now with a 8cuft enclosure you'll have a -3db point of about 19hz, with the same 18hz port tuning. My app shows you'll still be under xmax with 900w rms with both the 6.5cuft, and 8cuft net enclosures. I'd have someone run this through WinIDS to get more accurate results.
 

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The inuke3000 puts out around 600 watts or less for sub duties at 4 ohms. The bigger you go, the more efficiently those watts will be utilized as you are probably aware. FWIW, I built two 3 cft sealed cabs with these subs and tried to power them with the inuke 3000 and it just wasn't enough juice. We stepped up to the nx6000 and that did the trick.

You will likely be fine with the 3000 and ported.
 

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Discussion Starter #5
This is what I came up with using "Speaker Box Lite" app on my phone. With a 6.5cuft net enclosure and a 18hz port tuning you'll have a -3db point of about 21hz. Now with a 8cuft enclosure you'll have a -3db point of about 19hz, with the same 18hz port tuning. My app shows you'll still be under xmax with 900w rms with both the 6.5cuft, and 8cuft net enclosures. I'd have someone run this through WinIDS to get more accurate results.
Thanks...

So again I am a modeling newbie. How do I set the "tuning" or is that a net result of the design parameters?

If you were building dual 15" ported subs, what would you target for a box design (size, port type/size)?
 

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Sorry, I don't even have WinISD. You'll have to wait until until a experienced WinISD user chimes in and helps you out.
 

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Thanks...

So again I am a modeling newbie. How do I set the "tuning" or is that a net result of the design parameters?

If you were building dual 15" ported subs, what would you target for a box design (size, port type/size)?
The tuning is somewhat going to be a net result of the design. It'll kind of depend if you're targeting a certain frequency or just trying to go as low as possible? If trying to go as low as possible, you'll need to set the port length as long as reasonably possible in your layout. If you're targeting a frequency, then you'll somewhat have to build your box around that.

I dont think you can go wrong with the GSG packs.

I also have dual UM15's, and I went with this design (Dual 15” Dayton 390HO Nearfield Slim Build). It's too small for the UM15's, so I do lose some low end. Because of that, I have a V2 that I'm currently doing and making slightly larger. The trade off for me? Maximum WAF because the subs are 100% hidden behind the couch. I'm still very happy with the sub's and performance.

Go for the mini marty if you need a compromise with the spouse? Or, totally DIY and get something that maybe fits your situation a little better.
 

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The Marty 15 looks to be only about 2db at 20hz compared to the Mini Marty you're contemplating. If the the Marty 15 having about 2db less output at 20hz isn't that important to you, I'd go with the smaller, less expensive Marty 15. Food for thought.
 

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Discussion Starter #10
OK. So I just finished a long weekend with my youngest daughter getting married, and while there is still days worth of things to do (returning rental items, sorting through decor, gifts, moving her stuff, etc), I want to get back into planning this.

Anyone have any design advice for the UM15-22s? Thanks to those that chimed in with thoughts on the box size, but I still struggle with what would be ideal port sizes, or if the previously mentioned flat packs for 18" woofers would still work with 15" woofers for overall volume and port sizes, etc...

Thanks again.
 

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this link, in post 8 Dual 15” Dayton 390HO Nearfield Slim Build

I pm'd the builder, as I have 3 of the 390HO's
as there is only 1 pic in the post and
there are no dimensions listed for the port, no cut sheet
but
if you pm'd the designer, LTD02, and referenced that build thread,
and that you're wanting to use the UM-15"
the important thing here is the port dimensions, box size may not change much and that slim depth is a good feature
the tune is 22 hz, iirc
I think you could pull it off, maybe with a slightly deeper tune
 
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Discussion Starter #12
this link, in post 8 Dual 15” Dayton 390HO Nearfield Slim Build

I pm'd the builder, as I have 3 of the 390HO's
as there is only 1 pic in the post and
there are no dimensions listed for the port, no cut sheet
but
if you pm'd the designer, LTD02, and referenced that build thread,
and that you're wanting to use the UM-15"
the important thing here is the port dimensions, box size may not change much and that slim depth is a good feature
the tune is 22 hz, iirc
I think you could pull it off, maybe with a slightly deeper tune
Part of the problem is that the UM15-22, so I've been told, needs a big box to really perform.

Maybe I will mention him in this post and he could consider providing some pointers... I hate blindly calling someone into a discussion though. It comes across as "demanding" something from someone, which I really don't like doing.

OK @LTD02 , if you have time to interject some advice on ported box and port size for two UM15-22 subs powered by a single Behringer NX3000D, I would really appreciate it. If you don't, I completely understand and am sorry to have bothered you. I was hoping to keep things as far under the "recommended" 11cuft as possible, but do know that I will need something with some larger size to be effective with the UM15-22. Thanks.
 

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so you are going to run all these subs ? anyhow...im running 2 12's in a ported box at the moment but I did order 2 ultimax 15's and I dont have time for all the wood work so I ordered the sealed boxes from PE for them at same time. All of it was on sale so that pushed me to get them also. I will let you know how they sound soon as I mount the subs. I am going to run them off a Crown XTi2000 which I believe to be better amp than that behringer . I know totally not what you are going for but I will add my results sealed just for reference.
 

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so you are going to run all these subs ? anyhow...im running 2 12's in a ported box at the moment but I did order 2 ultimax 15's and I dont have time for all the wood work so I ordered the sealed boxes from PE for them at same time. All of it was on sale so that pushed me to get them also. I will let you know how they sound soon as I mount the subs. I am going to run them off a Crown XTi2000 which I believe to be better amp than that behringer . I know totally not what you are going for but I will add my results sealed just for reference.
I am going to play with running the two 12's up front and the two 15's in the rear of my theater. It could prove problematic with the different woofer sizes though. If so, I will probably look to sell the 12" subs and put the 15's up front.

The sealed box from PE isn't going to cut it for me. Too small, and I need/want ported. Mixing ported and sealed subs in the same room is more problematic than the different woofer size problem that I will have to try to sort out. The Ultimate 15s really need a large ported box (around 11cuft) to hit their rated numbers too. I do like the idea of the small 3cuft size though, but even if it stuffed full to "simulate" a large box, that is still like half the size of the ideal size. That is information that I've gathered from other people though that were going off of their understanding of the woofer and cabinet needs, and I don't think that any (or much) of that is from information from people that actually built that smaller box and put it in a room with other ported subs. A few reviews of the box did say that it lacked low end or that people were going to "upgrade" to ported at some point, but again, too many variables in their setups to know what they were working with for their room or amplification to know what issues they were experiencing.

Yeah, the Crown XTi2000 is a nice amp, but it was a chunk more money and isn't available any longer. The current model XTi2002 is $780 new. I got my NX3000D for $350 new. If the XTi2002 55% better than the NX3000D? Probably not.
 

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I checked at PE, 11 cu. ft.
My Honda sub, using a um-10, didn't have enough room to make a box big enuf for the ports . .
and if we had a pic of your space and the placement places and important stuff like that
it could help
but, to keep within the need for the smaller box but looking for the lowest tune
the PE tech suggested using PR's to replicate the "physics" that a port would, for the most part, produce the desired / bodacious tune,
it's an inquiry that might help

 
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Discussion Starter #16
Space is 14' wide x 24' deep with a ceiling just under 8'.

Space behind my two rows of seats is plenty wide and tall and about 27" deep between it and the rear wall. I mean I could put full marty setups back there, but if I can get by with something a little smaller with most of the benefit, that is the goal.

If I ever move them up front behind my screen's false wall, I have about 30" of depth, 30" of width, and tons of height to fit within.
 

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well, ya know,
IF that huge frontal space IS so available 30 x 30. . .and the 15's . . .
ask over at the Bill Fitzmaurice site if the um is an acceptable driver for a THT / THTLP.
join and ask . . .
actually, you can start to do that by comparing specs over at PE.
the 390HO is one recommended driver for those 2 designs and some variance is allowed, based on questions I've noticed over a few years. I built 3 of the THTLP's with that driver and as a major ROI for clean effortless woofage, they will blow you away, even the nx3D is also most too much . I cannot run my 3 x BASH 300 amps at full crankage
but co-location wrt MLP would really up the ROI for running EQing both off 1 channel.
While the boxes do get large, 19 cu. ft and above , behind the screen space would be very tempting .
the THTLP depth is only 18" and with a 15, you could go as wide as 36". the extra width makes for smoother response.
the one down side isthat the design rolls off at 22 hz but there is the possibility for room gain and extra that may be added by applying DSP.
the THTLP has a design for side firing which would be looking good in that space as it would then be firing into the room.build 2 at 28 or 30" deep and buckle up.
if you were to post the specs for each, some guru here might be able to discern the negotiable differences.
also, I recently made a stand to have my 24" sub fire down at the floor, loading distance is 18" or so. in a corner.
The result was immediately huge.
also, post more room specs
 
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specs in post 16 -missed that
at 14" wide behind the screen, 4 THTLP's 24" or 30' wide firing downward, 2 on each channel of the berry.
each would be about 19 or 23 cu, ft.
large? yes.
This is where the debate of FLH vs. ported vs, cleaner bass vs no HPF needed vs. power unlimited and high efficiency and on and on . .
risers an easily be built out of uni-strut.
 

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As I said, I am terrible at modeling, but I've been trying.

In WinISD, I modeled the following:
Full 18" Marty sub flat pack from GSG, but with a cutout for a 15" woofer
Mini 18" Marty sub flat pack from GSG, but again with a cutout for a 15" woofer
Marty 15 sub flat pack from GSG
Kuda 15 sub flat pack from DIYSG
Parts Express' 3cuft SEALED flat pack (just as a reference of what a number of people seem to have done. I don't want to go sealed.)

The Full 18" Marty seems the "winner," but I'm not sure how much "better" it is over the Mini 18" Marty that is 8" shorter (and easier to get wife approval, or at least fewer wife complaints. LOL)

Any thoughts from people?

Again power will come from a NX3000D (rated at 900 watts per channel at 4 ohms, but heard this is closer to 600 watts in reality.)

Thanks.
if your up for some wood working

id suggest if your going for the max spl fq down into the 20s an xmax go with a pair of the Fi Car Audio IB315 v2 S2

at 2 ohms an feed it 775 watts from a crown xls 1502 (which i have myself)

i plan to use in my build its a ported 2.905ft3 cabinet tuned to 19.85hz
all the wall of the cabinet are to be 1.5in thick

assembled from
26 Pressure Treated Lumber beams at 2-in x 12-in x 10-ft #2 Prime

cut into four 13 layer stacks two for each cabinet when sandwiched togather

each cab will be 19.5in wide by 56in tall by 13.75in deep a sallow footprint

with a 72.5in labyrinth flare port

the total cost of wood with shipping a tax is 350$ near the same price for both

the 15in an 18in marty twin packs but before ther shipping an tax

i had a custom metal stencil made by send cut send that will allow me to make flawless
router cuts plus ill use some 3in drywall screws between each layer plus some

Loctite PL Premium Polyurethane Construction Adhesive


3028127



3028124


3028125

if your interested this is the link to my google cloud to access the winisd config file an the dxf file to have send cut send do it up from .125in mild steel
it ran my under 160$ to have it made an delivered

iv yet to get the wood

 
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