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Discussion Starter #1,121
I did more experimentation with top hatch Minis, this time with a SAN 214.50, the results are surprisingly good for a 21" in 40x25.5x24. The sim is 1000 watts with a 18Hz 3rd order HPF active. Tune works out to 19Hz.





 

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Yamaha RXa2060 - HTM12 / Pa460 3way LCR - Volt10s atmos - HT8s rears - (4) Dual JBL Devs - (2) F20s
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@Red Five
If the mini v2 high compression is only 5 inches.... 6 inches (?) taller but gains almost 5db on the left and has almost similar tune, why would you want to sacrifice that much for 6 inches?

I’m not discrediting you, I am only questioning for research purposes.

I do like the top hatch design but how much gains are you really getting vs what you already have?
 

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Discussion Starter #1,123 (Edited)
@Red Five
If the mini v2 high compression is only 5 inches.... 6 inches (?) taller but gains almost 5db on the left and has almost similar tune, why would you want to sacrifice that much for 6 inches?

I’m not discrediting you, I am only questioning for research purposes.

I do like the top hatch design but how much gains are you really getting vs what you already have?

That sim is running 91 volts, so that is around 1600 watts into 5.2 Ohms vs this sim 1000 watts normalized. 4 cuft can add about 2db of output at the same tune. Velocity is on the high side for the V2. If you are space bound and really want a 21" this would let you push power into it for about 118db. I would compare the Mini V2 against the Mini V3, since both occupy the same volume at slightly over 18 cuft. The V3 will give you the deeper tune at 17Hz as a trade off that was made. This I would compare to something in the same form factor, Mini 18 V5 or Mini 18 V1. This one could handily beat them by 3db since it can handle more power than either of those two boxes since it is loaded with a 21" and not an 18".
 

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Discussion Starter #1,124
Mini Devastator 21" Version 3 HCR

The top access panel is awesome for stuffing longer vents in a cabinet :) This means another Mini Devastator version is very much necessary. Very similar to the Version 2 Mini the Version 3 Mini adds a longer vent to the mix for a 17Hz tune. The simulation is based on the SAN214.50 receiving 1000 watts of power with a BW 17Hz 3rd order high pass filter active. See more detailed screen shots of the top hatch in the 18" Mini Version 5 post.


























Cut list (in.) based on 3/4 material



 

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Hey gang. The build is almost done! Just finishing the sides and edges, and waiting for some components. Along with the subwoofers...

Yes... the subwoofers aren't here. But the boxes are done...

:(:(:(

I read in some build threads the importance of fitting the subwoofers BEFORE completing the build.

Are there any precautions that I can take to ensure the subwoofer has clearance?

I cut the baffle to the 16.6 inch specification on the B&C site.

Should I just place, mark the outside to ensure that it is center, then pre drill?

Or should I replicate my cutout on another piece of wood to mimic?

I will have the build mostly complete this weekend, but will not get my plexi glass until next week.

As always appreciate any advice, and much love my DIYvastator friends!

Edit:

Concerning the plexiglass, it will be glued to the front panel, and I do not have visibility of the front opening at this time.

I guess I could cut a strip out of the front and fix it for when the plexi will be applied worst case scenario.
 

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Discussion Starter #1,126
Hey gang. The build is almost done! Just finishing the sides and edges, and waiting for some components. Along with the subwoofers...

Yes... the subwoofers aren't here. But the boxes are done...

:(:(:(

I read in some build threads the importance of fitting the subwoofers BEFORE completing the build.

Are there any precautions that I can take to ensure the subwoofer has clearance?

I cut the baffle to the 16.6 inch specification on the B&C site.

Should I just place, mark the outside to ensure that it is center, then pre drill?

Or should I replicate my cutout on another piece of wood to mimic?

I will have the build mostly complete this weekend, but will not get my plexi glass until next week.

As always appreciate any advice, and much love my DIYvastator friends!

Edit:

Concerning the plexiglass, it will be glued to the front panel, and I do not have visibility of the front opening at this time.

I guess I could cut a strip out of the front and fix it for when the plexi will be applied worst case scenario.

The good news, you have an open front, if the alignment is that off you should be able to see it. If you could put the cabinet on saw horses you could check the alignment from the front side before committing to drilling holes or even pencil marking. If it looks good from the front, take a pencil and outline the woofer, you should see if you are centered once the woofer is removed. :)
 

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Hey gang. The build is almost done! Just finishing the sides and edges, and waiting for some components. Along with the subwoofers...

Yes... the subwoofers aren't here. But the boxes are done...

/forum/images/smilies/frown.gif/forum/images/smilies/frown.gif/forum/images/smilies/frown.gif

I read in some build threads the importance of fitting the subwoofers BEFORE completing the build.

Are there any precautions that I can take to ensure the subwoofer has clearance?

I cut the baffle to the 16.6 inch specification on the B&C site.

Should I just place, mark the outside to ensure that it is center, then pre drill?

Or should I replicate my cutout on another piece of wood to mimic?

I will have the build mostly complete this weekend, but will not get my plexi glass until next week.

As always appreciate any advice, and much love my DIYvastator friends!

Edit:

Concerning the plexiglass, it will be glued to the front panel, and I do not have visibility of the front opening at this time.

I guess I could cut a strip out of the front and fix it for when the plexi will be applied worst case scenario.

The good news, you have an open front, if the alignment is that off you should be able to see it. If you could put the cabinet on saw horses you could check the alignment from the front side before committing to drilling holes or even pencil marking. If it looks good from the front, take a pencil and outline the woofer, you should see if you are centered once the woofer is removed. /forum/images/smilies/smile.gif
Hey, Red!

Thanks for the reply. Sadly my front is not open, and I am flying the plexi directly to the front panel 😞

Should I just go ahead and cut it open 😕

Hmmm...

I could make the hole a little bigger and build a small circle ledge and affix the subwoofer to that?
 

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Discussion Starter #1,128
Hey, Red!

Thanks for the reply. Sadly my front is not open, and I am flying the plexi directly to the front panel 😞

Should I just go ahead and cut it open 😕

Hmmm...

I could make the hole a little bigger and build a small circle ledge and affix the subwoofer to that?

Trial and error would be the best approach, drop the woofer in close to what you think is centered pencil around it, see how much it needs to move in any give direction. It will probably take a couple tries.



Edit: if you have a picture of where you are at to share that can also help us with ideas.




-John
 

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Hey, Red!

Thanks for the reply. Sadly my front is not open, and I am flying the plexi directly to the front panel 😞

Should I just go ahead and cut it open 😕
Hmmm...

I could make the hole a little bigger and build a small circle ledge and affix the subwoofer to that?

Trial and error would be the best approach, drop the woofer in close to what you think is centered pencil around it, see how much it needs to move in any give direction. It will probably take a couple tries.



Edit: if you have a picture of where you are at to share that can also help us with ideas.




-John
Got it! 😉

Thanks again. I’ll mess around with it to see where I land. Currently all but the finish work, paint, hatch, and accessories are left 🙂

Really dig the new low tune build with the top hatch btw! As Juju said, my mind is already looking at placement for more little ones haha... that Quad JBL is rockin’.
 

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I read in some build threads the importance of fitting the subwoofers BEFORE completing the build.

Are there any precautions that I can take to ensure the subwoofer has clearance?

I cut the baffle to the 16.6 inch specification on the B&C site.

Should I just place, mark the outside to ensure that it is center, then pre drill?

Or should I replicate my cutout on another piece of wood to mimic?
As long as you cut it to spec, no clearance issues.

As for centering the driver...
The cutout is 16.6”, and the driver is 18” OD.

Take a sharpie, and tape a piece of coat-hanger or heavy wire to it like so:



Excuse the phone drawing.

Set the wire to allow you to draw a roughly 1” offset on your cutout. Doesn’t have to be exact size at all.

Visually center the driver in the drawn circle, and it will be centered in the cutout.

Chris
 

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Anybody knows if a PA460 would work in a BMD Ultra Shallow ?
After a quick look at the PA dimensions, i think it’s going to fit in this box but will it play well ?

I have a Beringer EP4000 that is sitting here, collecting dust ! I need to do something with it and my system definitely need more punch.
I already have 4 sealed UXL powered by 2 NU60000 and they give me plenty of ULF but lack in the midbass region.
So i’m looking to build 2 DEV that are going to be placed behind my A/T screen with my 1099 LCR. I only have 18’’ behind the screen so the Ultra Shallow would perfectly fit there.
 

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The top access panel is awesome for stuffing longer vents in a cabinet :) This means another Mini Devastator version is very much necessary. Very similar to the Version 2 Mini the Version 3 Mini adds a longer vent to the mix for a 17Hz tune. The simulation is based on the SAN214.50 receiving 1000 watts of power with a BW 17Hz 3rd order high pass filter active. See more detailed screen shots of the top hatch in the 18" Mini Version 5 post.
Where's the bracing issue in the front chamber pertaining to using the front panel as a hatch?
 

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Yamaha RXa2060 - HTM12 / Pa460 3way LCR - Volt10s atmos - HT8s rears - (4) Dual JBL Devs - (2) F20s
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Anybody knows if a PA460 would work in a BMD Ultra Shallow ?
After a quick look at the PA dimensions, i think it’s going to fit in this box but will it play well ?

I have a Beringer EP4000 that is sitting here, collecting dust ! I need to do something with it and my system definitely need more punch.
I already have 4 sealed UXL powered by 2 NU60000 and they give me plenty of ULF but lack in the midbass region.
So i’m looking to build 2 DEV that are going to be placed behind my A/T screen with my 1099 LCR. I only have 18’’ behind the screen so the Ultra Shallow would perfectly fit there.

I already had a conversation with Red about this.


 

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Hey, Red!

Thanks for the reply. Sadly my front is not open, and I am flying the plexi directly to the front panel 😞

Should I just go ahead and cut it open 😕

Hmmm...

I could make the hole a little bigger and build a small circle ledge and affix the subwoofer to that?

Trial and error would be the best approach, drop the woofer in close to what you think is centered pencil around it, see how much it needs to move in any give direction. It will probably take a couple tries.



Edit: if you have a picture of where you are at to share that can also help us with ideas.




-John
Not a picture of the current dilemma, but wanted to share 🙂

Using self leveling expoxy on the front to make sure the plexi is flat (had some out of square the fix with the ledge).

Black grill will be on the left.

And ofc will be treating with duratex.
 

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I read in some build threads the importance of fitting the subwoofers BEFORE completing the build.

Are there any precautions that I can take to ensure the subwoofer has clearance?

I cut the baffle to the 16.6 inch specification on the B&C site.

Should I just place, mark the outside to ensure that it is center, then pre drill?

Or should I replicate my cutout on another piece of wood to mimic?
As long as you cut it to spec, no clearance issues.

As for centering the driver...
The cutout is 16.6”, and the driver is 18” OD.

Take a sharpie, and tape a piece of coat-hanger or heavy wire to it like so:



Excuse the phone drawing.

Set the wire to allow you to draw a roughly 1” offset on your cutout. Doesn’️t have to be exact size at all.

Visually center the driver in the drawn circle, and it will be centered in the cutout.

Chris
Thanks for the tip, Chris. I may have a compass I can tape up.
 

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Discussion Starter #1,136 (Edited)
Where's the bracing issue in the front chamber pertaining to using the front panel as a hatch?
It becomes a long list of issues now that I have thought it over. The cab would most likely end up with a double baffle wall, about about a dozen additional parts in the front chamber. I am cutting out about 20 some odd inches of the front rails, they are what give the Dev it structural integrity. Most rear bracing is for panel resonance, not inertial dampening. The front rails even on a clear fronts are really what is keeping things from vibrating, they are not going to resonate or let the front panel resonate much. The front hatch would require more bracing that what I have done for the rear hatches. The rear chamber has much larger cross sectional area in most cases by the driver, the energy will have disappated over a larger area versus the front chamber where I am a little under a 2:1 ratio. Definitely extra mass on a front hatch

Some unknowns with how bacing in the QW will effect end response. A few parts can be taken out of the back and switched up somewhat. The only benefits for the front hatch I can come up with are the same port routing options as the top hatch and a bit easier driver install. I am adding complexity and losing displacement efficiency as a couple trade-offs. I have put a lot of effort into eeking as much as I can out of the gross volume. The assembly order would most likely need to be rethought, it will require some special considerations at a glance without really diving deep into a mock-up. If you are very picky with fit an finish, having a hatch on the front might not be the best thing for OCD and getting it perfect.
 

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Discussion Starter #1,137
This is the smallest box for cramming a 21" on the inside of a Devastator with a 20Hz of less tune.
@tarponater just a heads up this box is going to exist!
 

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I have OCD and I never bothered to paint my enclosure in 8 years! Ease of speaker installation and voicecoil venting are my only concerns when it comes to enclosure construction.
 

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That enclosure in an SUV or minivan would be AWESOME!
 

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I already had a conversation with Red about this.


Wow, that’s exactly the kind of info i was loooking for !!!
Looks like there’s going to be 2 new BMD Ultra Shallow behind my screen in the next weeks :)

Thanks !
 
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