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Discussion Starter · #1 · (Edited)
The number of versions and different builds of Devastators keep multiplying, it would be nice if some of this information were kept more neatly in one place. This thread will be a work in progress and is on the project list :) I will add new variants to this thread and link below. Note, the SAF version is getting a revision that shrinks it down more yet keeps SPL mostly the same. If you are interested in custom Devastator please send me a PM. The boxes are listed in chronological order.

I would suggest taking measurements of different locations in your room and then select boxes that best fits the location. The goal is using peaks in locations so you get a strong summation of those multiple locations at the MLP. Some locations might peak well with a BMD, other locations might peak better for the Mini or just a regular Devastator. The Devastators offer higher efficiency over a direct radiator configuration in most cases (30Hz on up) or keeping the 20Hz to 30Hz region more flat than a BR cabinet with the same displacement. Why not leverage the efficiency as much as possible? :)


Does my UM18 work in a Devastator? The short answer is no, it does not work in a Devastator. This is a UM18 in a Mini Devastator 18 Version 6.



As you can see the woofer gets a very sharp peak at the resonant point of the front horn of the cabinet. You might be thinking why not just EQ that peak? Here is the problem, the UM18 will ring when loaded in a Devastator, the cone stays in motion after a impulse. This is the UM18 vs the 18TBW100, pink is the UM18, green is the TBW. Notice how the cone on the TBW stops moving relatively quickly. Some subs are designed to work well in higher order band pass boxes, others are designed to work in lower order band pass boxes. There is a simple method for finding a good woofer using a specific metric. Efficiency Bandwidth Product (EBP), the woofers Fs value divided by its Qes value. The Devastator starts working once a value gets around 70 or so. Values closer to 100 are better, but not absolutely necessary. If you have a woofer with a value higher than 70 and are curios to see how it looks, just post a message in the thread :)



21" comparison chart of common variants (thanks Chris!) 1000 watt normalization with HPF active.






PLEASE SHARE BUILDS IN THIS THREAD!!! (including pictures)

Designs (note first link has most of the guiding information in the original Devastator thread + the Mini Devastator build guide near the bottom of the post)

Broken down by woofer size:

24"
21"
18"
15"
12"
Build threads/other
Guides
 

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This is a great idea and will make things much smoother for people wanting to build these.

Sent from my SM-N950U using Tapatalk
 

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Discussion Starter · #3 ·
This is a great idea and will make things much smoother for people wanting to build these.

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That would be very helpful! If the pictures were in order with one sentence summaries of what needs to happen at each step that would be very helpful.
 

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That would be very helpful! If the pictures were in order with one sentence summaries of what needs to happen at each step that would be very helpful.


I’ll be honest that was my original intent but you get so caught up in the build you forget to take pictures of every step. Super good idea red five hats off to you for your help and support.

Ps don’t forget to add the MBM ;) that will be coming to to a home very near me!


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Discussion Starter · #5 ·
I’ll be honest that was my original intent but you get so caught up in the build you forget to take pictures of every step. Super good idea red five hats off to you for your help and support.

Ps don’t forget to add the MBM ;) that will be coming to to a home very near me!


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The Mini MBM, the LBM, BMD MAX, 30" wide almost v1 and a new 18 inch version are on the eventual list. I should make an MBM version of the v1 tuned around 28Hz. :)
 

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Maby list the response for each in the first post. The names don't tell the full story. Like the -3db or -6db response.
Gives a nice and fast overview.

Ps. Great work on the designs :)
 

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Discussion Starter · #7 · (Edited)
Micro Devastator MBM 15"

Here is the Micro Devastator MBM! (going with micro something else might be a mini....) Comes in at an external 7.5 cuft, nice small foot print. Primary function is a two way configuration with the BMD MAX NSW to hit the mid bass really hard. Though it should work well with big ported HT drivers that lack the chest kick. Recommended crossover point is 60Hz. A 2nd order HPF for the micro and a 4th Order filter for the accompanying sub is recommended.


Sub drivers of choice. The Lavoce WAF154.00 or the B&C 15TBW100. Note not that usual panel overlaps. The Dayton PA380 is also viable, but power handling and excursion is more limited. Screen shot attached at the bottom.





2000 watts or 107.7 volts of power 45Hz 2nd HPF.






Particle velocity with 2000 watts of port and horn. Dark Port light horn 45Hz 2nd Order HPF active.










More detailed screen shots in the attachments!
 

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Discussion Starter · #8 · (Edited)
The BMD MAX 21"

This is the BMD MAX! The sub is built to handle the wrath of the Eminence NSW6021-6. Not too much has changed from the base BMD model. HPF 19Hz 2nd order should keep things in check. 95 volts = roughly 2.38 kw with 3.8 Ohms of load. The main goal of the design was keeping port velocity under 25m/s.











 

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Discussion Starter · #9 · (Edited)
The Mini Devastator 18" Box Size 40"x25.5"x24"

Tune on the box is 20Hz, this was squeezing all I could into the space, if you want a lower tune you can plug ports. The first port usually drops the tune 4Hz or so. External volume is only 14.2 cubic feet :) Preferred drivers are the LaVoce SAF184.03 and the SAN 184.03, the PA460 will work. I would also assume the 18TBW100 will work very well and the 18DS115 will work, but port velocity is high due to the stronger motor and higher excursion capability. The center of the sub woofer cutout is 10 inches from the top of the baffle panel. Assembly guide.






1300 watts or 87 volts, 20Hz 2nd order HPF.






PA460 1w1m vs the VBSS






Assembly order is mostly the same as a regular Devastator, the rear port board goes up the back panel and that is the main change.


















EQ setting for close to flat.

 

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Here is the Micro Devastator MBM! (going with micro something else might be a mini....) Comes in at an external 7.5 cuft, nice small foot print. Primary function is a two way configuration with the BMD MAX NSW to hit the mid bass really hard. Though it should work well with big ported HT drivers that lack the chest kick.


Sub drivers of choice. The Lavoce WAF154.00 or the B&C 15TBW100. Note not that usual panel overlaps. The Dayton PA380 is also viable, but power handling and excursion is more limited. Screen shot attached at the bottom.

OMG now your killing me. I've been debating replacing my entertainment center (link) with two larger shelf type units (one with AVR+5channel amp + Sources, the other with my 4 sub amps) and then spacing them out wider (moving to a 85" TV soon) and then using the area previously taken up by that entertainment center (63"W x 28"H x 20"D) for subs and my future center (which is 14" high).......

Two of these would fit in there side by side decently and work with the height I was wanting to go with too. I'd cover them (and the doors on the towers) with speaker fabric and they'd be "stealth"...

OK, is there going to be a flatpack of these by any chance? If not, I'd likely talk to the folks Mike uses in Chicago to at least cut everything down for me..... but a flatpack would still be easier (albeit more costly)......


GRRRRR ****Wheels spinning****
 

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Discussion Starter · #11 ·
OMG now your killing me. I've been debating replacing my entertainment center (link) with two larger shelf type units (one with AVR+5channel amp + Sources, the other with my 4 sub amps) and then spacing them out wider (moving to a 85" TV soon) and then using the area previously taken up by that entertainment center (63"W x 28"H x 20"D) for subs and my future center (which is 14" high).......

Two of these would fit in there side by side decently and work with the height I was wanting to go with too. I'd cover them (and the doors on the towers) with speaker fabric and they'd be "stealth"...

OK, is there going to be a flatpack of these by any chance? If not, I'd likely talk to the folks Mike uses in Chicago to at least cut everything down for me..... but a flatpack would still be easier (albeit more costly)......


GRRRRR ****Wheels spinning****

I have not had a conversation with Kevin about any of the variants yet... for now it is full DIY.
 

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I have not had a conversation with Kevin about any of the variants yet... for now it is full DIY.
No worries, in my excitement I failed there was a reason it was smaller....... it uses smaller drivers.... *DUH*...

I need larger drivers given the amount of space I have to fill, and the distance from the main LP...

I may still do something like that, but I'd likely need the larger variants (using 18 or 21" drivers)......

Thanks for letting me know these are full DIY. Makes sense.

Thanks for at least putting together all the graphs and plans. Thats a huge undertaking....
 

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Discussion Starter · #13 ·
No worries, in my excitement I failed there was a reason it was smaller....... it uses smaller drivers.... *DUH*...

I need larger drivers given the amount of space I have to fill, and the distance from the main LP...

I may still do something like that, but I'd likely need the larger variants (using 18 or 21" drivers)......

Thanks for letting me know these are full DIY. Makes sense.

Thanks for at least putting together all the graphs and plans. Thats a huge undertaking....

Well diaphragm size matters less as the frequency goes up. For every octave you go down, you need 4x the displacement to achieve the same level of efficiency. That is a good zone for running a 15 inch woofer. It only has to reach into the mid 50s region. 134db, is 134db with bass, but a 18 in a bigger box with a stronger motor could get a few more db potentially.
 

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I'm really curious about how this models with the PA460 vs the VBSS cab. Any chance you could plot this?
 

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Discussion Starter · #15 · (Edited)
I have the apples to apples comparison normalized to 1w1m. Then there is the 330 watt graph pushing close to 11mm of excursion which is the max for the 460. The outcome is expected, down about 8 db.





 

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Well diaphragm size matters less as the frequency goes up. For every octave you go down, you need 4x the displacement to achieve the same level of efficiency. That is a good zone for running a 15 inch woofer. It only has to reach into the mid 50s region. 134db, is 134db with bass, but a 18 in a bigger box with a stronger motor could get a few more db potentially.
Gotcha. Once I get things kinda finalized I will PM you with the space I've got available and what parameters I'm looking at, and we can discuss if any of these are a good idea. The issue is likely going to be my limited (for a horn) depth at around 22-24", which may limit the driver size choice for a horn, but not as much for just ported.

**Off Topic** Right now I've got WinISD open with a pair of 21's in 16cf tuned to 15hz @ 3m and the sims look good with port velocity in check.
 

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Discussion Starter · #17 ·
Gotcha. Once I get things kinda finalized I will PM you with the space I've got available and what parameters I'm looking at, and we can discuss if any of these are a good idea. The issue is likely going to be my limited (for a horn) depth at around 22-24", which may limit the driver size choice for a horn, but not as much for just ported.



**Off Topic** Right now I've got WinISD open with a pair of 21's in 16cf tuned to 15hz @ 3m and the sims look good with port velocity in check.
Well we can talk about it later. If you go 30 wide I can get an 18DS115 to do a lot. The horn cross sectional area is relative to the subs Sd. An 18 will be easier to keep shallow vs a 21".
 

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Tune on the box is 20Hz, this was squeezing all I could into the space, if you want a lower tune you can plug ports. The first port usually drops the tune 4Hz or so. External volume is only 14.2 cubic feet :) Preferred driver is the LaVoce SAF184.03 the PA460 will work. I would also assume the 18TBW100 will work very well and the 18DS115 will work, but port velocity is high due to the stronger motor and higher excursion capability. The sub woofer cutout is 10 inches from the top of the baffle panel.






1300 watts or 87 volts, 20Hz 2nd order HPF.









Assembly order is mostly the same as a regular Devastator, the rear port board goes up the back panel and that is the main change.
















Hello Red Five,


Can you explain more on "The sub woofer cutout is 10 inches from the top of the baffle panel." Should I mark 10" from the top and use it as the center for the circle?
 

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Discussion Starter · #19 ·
Hello Red Five,


Can you explain more on "The sub woofer cutout is 10 inches from the top of the baffle panel." Should I mark 10" from the top and use it as the center for the circle?

Correct, I will change the wording.
 
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