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Discussion Starter · #1 ·
When I built my Maelstrom X sub, Army was instrumental in helping me with my design, so I was hoping he (and possibly others) would give me his/their opinion on another design.


The design will incorporate 4 EHQS 12 (4ohm version) drivers in a tower configuration with a slot port at the top (or bottom).


The inner dimensions of the box are 20" wide x 60" tall x 21.5" deep for a gross internal volume of 14.93 ft^3. After subtracting out .675 ft^3 for bracing, drivers, and port material, I come up with a net internal volume of 14.26ft^3.


The slot port measurements are as follows: 20" wide x 3.75" tall x 23" deep for what I believe (or was told) to be around a 23hz tune.


For an amp, I will be using a Buttkicker BKA1000-4A (1000watts into 4ohms) or 250watts into each of the four drivers. The four drivers will be wired in series/parallel to deliver a 4ohm load to the amp. Hopefully, it will not burst into flames-


The specs for the drivers are as follows:

Qts : .375

Qes : 0.49

Qms : 1.506

Fs : 25 Hz

Re : 1.8

Vas : 157 L

MMS : 90g

BL : 7.2 Tm

SPL : 89.1 dB

SD : 510 M^2

Xmax : 9.1 MM


Magnet Width : 5.25"

Cutout : 11.00"

Mounting Depth : 5.00"

Total Height : 5.60"

Displacement : .04 cF

Outside Diameter : 12.00"


I am including a drawing of a side view of the port construction, a dimensioned front view, and a crudely rendered drawing of the cabinet.


So, I guess I would like to know:

1) Is the design sound?

2) Will I have to worry about over excursion issues with this amp?

3) Any improvements that you would suggest?


Any input that you (and others) could give me on this design would be very much appreciated.


Thanks,

Micheal

Attachment 150672

Attachment 150673

Attachment 150674


 

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Quote:
Originally Posted by michealpuccini /forum/post/17042731


Hopefully, it will not burst into flames-

That would be funny... if it wasn't a real possibility



I didn't get a chance to look over your plan as it's late but wanted to let you know I haven't seen army around for quite some time... Maybe he's still lurking but just hasn't been posting for the last year or so? Looks like his last post in this forum was in November 08 and his last activity on the forum was in April.
 

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Discussion Starter · #3 ·
Well I guess it's been a while since I built my Maelstrom X! Hopefully, other members will take a look and post their thoughts. Again, I appreciate any advice you all can give me. I'm trying to (as always) measure twice and cut once (both figuratively and literally).
 

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I took some time to model what you're suggesting and it looks pretty good. Over-excursion shouldn't be a problem and air speed looks like it's well under control peaking around 16m/s. The box is a bit undersized for the four drivers but it will work just fine. One thing to note about the calculations, you have to remove the port volume from the enclosure as well. The port takes up pretty much exactly 1 cuft (.9982) bringing the volume down to 13.26 cuft. This threw me off as WinISD was giving me a tuning around 21hz but correcting the volume shows it to be closer to the 23hz you mentioned in the OP. The box being undersized the F3 is somewhat high around 33hz but you could add some boost around tuning to extend it. You'll want a high pass around 20hz as the excursion goes off the chart at that point.
 

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Only problem is that it's from a horrible company. I don't get why people like the idea of using lots of crappy drivers when they can just use one good driver. 4 EHQS 12 will be like a more efficient Shiva-X only. And that's assuming their rated Xmax is even accurate, and being a spec. from that company, that's not likely.
 

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Discussion Starter · #6 ·
Lennon_68,


Thanks for taking the time to model the project for me.


I have ordered a Reckhorn B-1 to use as a High-Pass filter.


Is there any way use could post the SPL graph from your model? I am trying to determine the effect of the (now) smaller sized internal volume on SPL. I have tried modeling the project myself using WinISD Pro, but (like always) my results don't seem anywhere near correct. I have included a screenshot of what my graph looks like. I have also included screenshots of the settings windows I used. Any ideas as to what I'm doing wrong?


Thanks,

Micheal

Attachment 150744

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Quote:
Originally Posted by michealpuccini /forum/post/17049331


Is this what your SPL graph looks like by chance?

Attachment 150755

It's similar but not quite the same. For example I show 93dB at 10hz and you're at 84dB (if I match the peak SPL by using 600W input signal). Did you add a high-pass filter for that graph?
 
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