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26" Cube, Maelstrom-X dual PR build

4811 Views 22 Replies 6 Participants Last post by  altahometheatre
I figure I would make a thread with my build. I made a variation on SturmMDs build and made it 26" so that I could center the PRs in the cabinet. I am using a Crown XS1200 to power this, 3kw at 4ohm mono. I have a Gen II Maelstrom-X, I had a Gen I, but it was defective and Kevin replaced it, so Kudos to him for awesome customer service. After bracing and drivers the internal should be about 7.5 cubic feet and modelling in winisd gives a tune around 17hz. I am using 14 washers on the PRs and have about 1750g total weight on them. I have tried the sub with various levels of fill and will get into that later. Using an SMS-1 with a 17hz subsonic filter to EQ and a Pioneer SC05 crossed over at 100hz. Feel free to ask any questions.

At the time I didn't have any tools (just bought a used table saw for $60 last week) so I had a cabinet maker friend help me build the enclosure. This is my first DIY anything.

We rounded over the outer baffle with a 1/2" roundover bit and a 1.25" on the outside of the box if my memory recalls.

The most work was probably the prepping for painting really. Betwen filling imperfections with wood putty, sanding, wiping down the entire enclosure, do a coat of primer, then do the same thing a time or two before we just sanded/wiped down and painted. It was a lot of work.

Then we started the black paint, we did 2 coats of black and then 1 coat of high gloss. Some of the pics are kinda dusty/fuzzy...sorry about that.

I did a lot of sanding, perhaps a bit more than I needed to, but I wanted a good looking enclosure.

Here is the finished product in my room:

I also bought a custom made subdude HD in a 26" cube configuration, I can take pics if you want and put them up.

At the moment I've been playing around with fill and things of that nature.
This is the uneq'ed mael with fill in my room

Here is a pic of the mael with 6-7 pounds of fill eq'ed

About half that

And then no fill

After a suggestion by Ricci, turned off all of the EQ and did a measurement from about 2" away from the center of the mael just to see what it would look like and this is it

After I did that I rememebered that my Ascend Sierra's put out the test tone sweep as well so I disconnected them and this is a nearfield measurement with nothing but the Maelstrom.

It sounds great, but the graphs show something kind of weird, I assumed that a sub should be relatively flat to it's tuning, but I get a big hump in the mix with no EQ, any thoughts?
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Looks great.... nice finish job!

The reason you are getting a peak in the measurement is your mic placement. It is 2" in front of the driver so the contribution of the Maelstrom is what dominates the measurement. You see very little of the output of the PRs. Imagine if you stood in front of a speaker at a rock concert and someone asked you how loud the speaker on the other side of the stadium was. That is what your doing with the mic and the PRs are on the other side of the stadium.

The SMS-1 measurement system isn't set-up for doing the type of gated measurement you would need to do a proper close-mic test. It is designed for in-room measurements, where you don't want to gate out the room contribution (that is a large part of what your EQing). Use it per the Velodyne instructions with the mic at the listening spot and you should get a better idea of what is going on.

Oh.... I see why your taking the close-mic. You wanted to confirm the tuning point. Looks like it is right-on if your goal was 18Hz. The FR measurement from there isn't valid though. As I said above, move it back to the listening spot and you get a better idea of the combined response (driver + PRs).

Kevin Haskins
Exodus Audio
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Absolutely, so far the mael doesn't even seem to break a sweat. It can take a lot of power.
You do have to be careful. Any driver can fail given the right circumstances. Sustained high power content near the tuning frequency of the PRs is one of the biggest dangers because the power dissipated across the coil is huge if you are pumping a couple KW into it and the driver's ability to dissipate that heat is greatly diminished when the driver isn't pumping.

Kevin Haskins
Exodus Audio
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