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I am totally new to building DIY subs. I have order Dayton Audio UM18-22 18 and iNukeNX6000D. Can anyone please guide me about the box dimensions and the internal bracing. Where i live it was pretty hard to get these alone so cannot get the box kit form parts-express :(/
 

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this one would be about 4.75 cubic feet net.

if those dimensions are no good, then they can be adjusted. anything from about 3 c.f. to as large as you want to go can work with your driver and amp.

4.75 c.f. is small enough that you most likely won't be able to overdrive the um18 on the low end with too much excursion. watch your power though and no sine waves. :)











good luck with your project.

you are the second guy in pakistan that i put a cab design together for this week. his was a big marty though. :)
 

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this one would be about 4.75 cubic feet net.

if those dimensions are no good, then they can be adjusted. anything from about 3 c.f. to as large as you want to go can work with your driver and amp.

4.75 c.f. is small enough that you most likely won't be able to overdrive the um18 on the low end with too much excursion. watch your power though and no sine waves. :)











good luck with your project.

you are the second guy in pakistan that i put a cab design together for this week. his was a big marty though. :)
Thanks a lot .... Actually the project if for a friend of mines... i am stuck off with Klipsch spl-15... very had to get these bad boys... but will defiantly get it some day ;)
 

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Thanks a lot .... Actually the project if for a friend of mines... i am stuck off with Klipsch spl-15... very had to get these bad boys... but will defiantly get it some day ;)
I just built a pair of sealed UM18s in dimensions very similar to those John provided you (a touch larger) - They pound. Your friend should be very happy with them.

I did set the limiter on my NX3kD to ~550 watts for each driver, as modeling showed I would be over xmax at about 450 if I recall correctly.
 

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I just built a pair of sealed UM18s in dimensions very similar to those John provided you (a touch larger) - They pound. Your friend should be very happy with them.

I did set the limiter on my NX3kD to ~550 watts for each driver, as modeling showed I would be over xmax at about 450 if I recall correctly.
xmax on that driver is overhang.

real xmax is up around 28mm. i'm not sure where the damage point is, but is likely way up in the 30's or so.

you can probably up your limiter somewhat. modeling for 28mm excursion at 10hz would be safe, though even higher should be fine.

also, the rest of the chain may have some rolloff, so excursion under 10hz probably won't be as high as models show.
 

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xmax on that driver is overhang.

real xmax is up around 28mm. i'm not sure where the damage point is, but is likely way up in the 30's or so.

you can probably up your limiter somewhat. modeling for 28mm excursion at 10hz would be safe, though even higher should be fine.

also, the rest of the chain may have some rolloff, so excursion under 10hz probably won't be as high as models show.

Excellent! I will re-model and bump up the limiter then.

Thanks for the info John!
 

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Excellent! I will re-model and bump up the limiter then.

Thanks for the info John!



Keep in mind, once the coil leaves the gap, there is still some fringe magnetic field. ( more for wider gap widths ) I'd expect the impedance to drop significantly ( regardless of frequency ) when the coil leaves the gap, towards the DCR of the driver.



Be careful approaching the limits.
 
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ah, found it:

so...
overhang = 22mm
gap height = 12mm
coil height = 56mm

therefore, xmax as calculated as overhang + 1/3 gap = 22 + 4 = 26mm
usable is typically at about overhang + 2/3 of gap or so = 22 + 8 = 30mm
coil leaves the gap at 22 + 12mm = 34mm (this is typically what is referred to as xdam or xmech, but i don't think this driver hard bottoms at that point)

winisd is "small signal" and in reality excursion doesn't go quite as high as model, so modeling for 28-30mm in your box with your power is probably aok.

"Our listed Xmax spec is "geometric" Xmax - the coil extends above and below the top plate by this amount (22mm).Because acceptance of Klippel specs isn't quite universal yet (but getting there), we give geometric Xmax instead of BL-limited Xmax to keep out of trouble, and it's also the most conservative measure. So coil height = top plate thickness + (2*22mm).

The top plate thickness for the UM18-22 is 12mm. So the overall coil height is 56mm, or just over 2.2"."

https://www.avsforum.com/forum/155-diy-speakers-subs/1500023-dayton-audio-um18-22-18-ultimax-released-15.html#post26312977

@smcmillan2
 

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I just built a pair of sealed UM18s in dimensions very similar to those John provided you (a touch larger) - They pound. Your friend should be very happy with them.

I did set the limiter on my NX3kD to ~550 watts for each driver, as modeling showed I would be over xmax at about 450 if I recall correctly.
I'm running 1200 watts into each of my UM18-22 drivers without any issues. I also do have 2 other subs so 4 subs sharing the load. See the Thread below as it breaks down the power numbers in a 6000DSP. I know you are using a NX3KD but the info in that thread is very useful.


https://www.avsforum.com/forum/155-diy-speakers-subs/2911854-nu6000dsp-amp-rundown-8.html
 

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4.75 c.f. is small enough that you most likely won't be able to overdrive the um18 on the low end with too much excursion. watch your power though and no sine waves. :)
Yes. Don't ask me how I know....:rolleyes:
 

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this one would be about 4.75 cubic feet net.

if those dimensions are no good, then they can be adjusted. anything from about 3 c.f. to as large as you want to go can work with your driver and amp.

4.75 c.f. is small enough that you most likely won't be able to overdrive the um18 on the low end with too much excursion. watch your power though and no sine waves. :)











good luck with your project.

you are the second guy in pakistan that i put a cab design together for this week. his was a big marty though. :)

@LTD02, I really like the bracing design you made on this. My sealed sub build for the UM18 which I am in the processing of building is 23" high 23" wide and 23" deep, can you please advise me will this bracing design actually be sufficient or shall I follow the parts express bracing style and try to create something like that?

Your design would be much easier to make, I would literally cut out the same driver cut out I did for the front baffle x 2 then use one of the boards to cut in half on my table saw and glue them together as your picture, however my only concern would be by looking at your picture there is no bracing for the first half inside the box, is this ok?

Thank you.
 

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I know a mini marty will provide lower and louder bass than a sealead enclusure. But what size for an enclosed enclosure would I need to go to get that performance ? Size isnt that much of an issue, but the build process is easier with a sealed box and to me it has better asthetics.
Thx.
 

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@LTD02, I really like the bracing design you made on this. My sealed sub build for the UM18 which I am in the processing of building is 23" high 23" wide and 23" deep, can you please advise me will this bracing design actually be sufficient or shall I follow the parts express bracing style and try to create something like that?

Your design would be much easier to make, I would literally cut out the same driver cut out I did for the front baffle x 2 then use one of the boards to cut in half on my table saw and glue them together as your picture, however my only concern would be by looking at your picture there is no bracing for the first half inside the box, is this ok?

Thank you.
tough to say exactly. since yours will be a little deeper, if you are concerned, a second layer is always an option. :)

i made the rear section a little longer so the braces would meet the circle (or close enough). that's just aesthetics though. equal spacing would be strongest, but i suspect it will be strong enough as shown. :)










and there is always 2x4's. :)

21.5" x 8.



 

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tough to say exactly. since yours will be a little deeper, if you are concerned, a second layer is always an option. :)



i made the rear section a little longer so the braces would meet the circle (or close enough). that's just aesthetics though. equal spacing would be strongest, but i suspect it will be strong enough as shown. :)





















and there is always 2x4's. :)



21.5" x 8.







Thank you so much LTD02. I Absolutely love the bracing in r1 - r5 with double inner panels. I assume the way the bracing will be within inside the box will not have any affect on the subs performance will it? Thank you so much for your help. I will do this method and post some pics later today :)

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...
I assume the way the bracing will be within inside the box will not have any affect on the subs performance will it?
...
so long as there is good room for air flow through and around the braces, it will not affect performance at all. r1-r5 is a very open layout, so no problems with that design. i look forward to seeing what you build!
 

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so long as there is good room for air flow through and around the braces, it will not affect performance at all. r1-r5 is a very open layout, so no problems with that design. i look forward to seeing what you build!
Thank you @LTD02. I was prepared to cut the bracing as you advised which would have been alot easier for me to do, when I noticed that the bracing mdf I cut was not the exact dimensions when placed vertically so it meant that I either had to get 12 pieces cut again with the correct sizes or I could make bracing that would fit horizontal into the box. So I had no choice other than creating my own measurements with bracing and trying to make them look like the parts express bracing system :) here are some pics... Again thank you so much for all your help. As always its very much appreciated and a shame I couldn't go that route as this way was very time consuming.



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I will do this method and post some pics later today :)
I was a skeptic but you proved me wrong, you are motivated!

Looking good.



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