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-   -   7.6 cu.ft Maelstrom- X 18" build (https://www.hometheatershack.com/forums/ported-subwoofer-build-projects/20266-7-6-cu-ft-maelstrom-x-18-build.html)

sub_junkie 07-30-09 10:18 PM

7.6 cu.ft Maelstrom- X 18" build
 

My Uncle and I have started working on my box. It will be around 7.6-7.8 cu.ft after bracing and everything is accounted for. There aren't many pictures becuase it is only about half way done. I will hopefully be getting more before it is done, and with the driver installed and in my room.

The box dimmensions are 48" tall and 20" deep and wide. We will have two window pane style braces. One near the top of the port about 2 inches away, and one about 5 inches above the driver. We will be runing a strip of thin wood between these two braces to help keep those braces "braced." lol.

The port is 18.50 inches wide, 2 inches tall, and 55 inches long. The length is divded into two parts, one 34 inches long, and another is 17 inches. There is a 45 degee piece of MDF that will go between these two pieces of wood which will keep the port at two inches from the back wall; I don't remember how long that one was though. There is also another 45 degree piece of MDF that is on the bottom of the port so that it will have better air flow. That also was cut the right length to keep the two inch spacing correct.

Drawing everything out first:

http://i536.photobucket.com/albums/f...rSale030-1.jpg

The cut outs ready for nailing and gluing:

http://i536.photobucket.com/albums/f...forSale031.jpg

http://i536.photobucket.com/albums/f...rSale032-1.jpg

The 45 degree angle for 17 inch part of the port:

http://i536.photobucket.com/albums/f...rSale033-1.jpg

Don't remember what this one was for, just looks like another cut out picture:

IMG]http://i536.photobucket.com/albums/ff323/airsoftsniperm4/UTGM324Gen3forSale034-1.jpg[/IMG]

Assemblig the slot port:

http://i536.photobucket.com/albums/f...rSale035-1.jpg

http://i536.photobucket.com/albums/f...forSale036.jpg

Roundover on the top of the port:

http://i536.photobucket.com/albums/f...forSale037.jpg

Port exit. The lighter piece of wood is for a better screwing place for the front pannel, as it will be just screwed on so it will be easier to maintain if needed. I will make sure that the holes will be pre-drilled so the wood won't split, although I am pretty sure my Uncle already knows this becuase he is a very experienced wood worker.

The port exit will have a roundover to help with chuffing and port noise.

http://i536.photobucket.com/albums/f...forSale038.jpg

A quick look at a Ford Ranger Pre-Runner by my house. They have around $150,000 tied up in that easily.


http://i536.photobucket.com/albums/f...rSale029-1.jpg

http://i536.photobucket.com/albums/f...rSale028-1.jpg


There is one neat thing that we might be doing for this box. Since the Mal-X wieghs in around 50 pounds we will be taking 1/2 inch steel and making a mounting ring that will go on the inside of the box, right where the mounting screws will be, so the screws have extra strength to support that weight. Hopefully, we will have it done, but my Uncle is really busy and might not be able to get that finished. We might be spraying on a bed liner to protect the box, but I will have to see how much it is first. Otherwise, I will just go with Flat Black. It will have a small roundover on all outside edges of the box to keep it from splintering if it hits a wall, of something, and it just looks better to boot.

Any questions or comments are welcome.

That's about it for now. More to come later. :bigsmile:

robbo266317 07-31-09 12:56 AM

Re: 7.6 cu.ft Maelstrom- X 18" build
 

Congratulations on finally getting underway, I'm sure you won't be disappointed as I'm still amazed at what the Shiva 12 can do in a big enclosure. Gotta love that Toccata & Fugue.
looking forward to more pics.
With the mounting ring are you going to tap it and use bolts to mount the driver?

Jugix 07-31-09 09:19 AM

Re: 7.6 cu.ft Maelstrom- X 18" build
 

2 Attachment(s)
Nice, you got things going, eh. ;)

So I threw the data in the unibox and it says you are going to end up with 14,6Hz tune when box is 7,6cf (215L). Pretty nasty port resonance just after 100Hz though.
Attachment 15061
Attachment 15062

Mike P. 07-31-09 02:06 PM

Re: 7.6 cu.ft Maelstrom- X 18" build
 

The first port resonance is 114 hz which may not be an issue since the port is folded. If it does cause an issue he can always use a lower crossover point.




sub_crazy 07-31-09 09:20 PM

Re: 7.6 cu.ft Maelstrom- X 18" build
 

Nice to see you got the build underway.

What are you going to use for a high pass filter?

I am most interested to see how it turns out as I still have another Mal-X sitting in the box waiting to be used and abused.

Have fun.

sub_junkie 08-04-09 12:07 PM

Re: 7.6 cu.ft Maelstrom- X 18" build
 

Quote:

robbo266317 wrote: (Post 179788)
Congratulations on finally getting underway, I'm sure you won't be disappointed as I'm still amazed at what the Shiva 12 can do in a big enclosure. Gotta love that Toccata & Fugue.
looking forward to more pics.
With the mounting ring are you going to tap it and use bolts to mount the driver?

I listened to Toccata and Fugue with my current sub, and needless to say, it was very overwhelmed.
The steel plate will be cut with a Plasma cutter as far as I can remember, and it will be tapped and I think we will use bolts. Not sure about that yet though.

Jugix, thanks for the graphs. When I modeled the slot port in WinISD, it said that the maximum port air speed was 26 or 29 m/s. I don't have WinISD on me right now, but will check again when I get back home. I am currently at Texas for my Grandpa as my dad, mom, and I drove his motorhome down for MD Anderson Cancer Treatment.

sub_crazy, I will be using a Reckhorn B-1 for the HPF, and a EP2500 in bridged mono as the amp. I will have a modest HPF set as not to stress the driver too much, and I will keep the levels down some :T
Didn't the EP2500 put out around 1900w in bridged mono operation?
Also, is the mounting cutout still 16.6 inches as the notes on Diycable says it is?


Thanks

sub_crazy 08-04-09 01:14 PM

Re: 7.6 cu.ft Maelstrom- X 18" build
 

You ever thought about using the ED eQ.2 instead of the Reckhorn? It is about $25 more but adds 2 bands of EQ along with the subsonic filter. I used one for my brothers set-up and for the price works well.

There was a place were you could get a refurbished eQ.2 for about $75 but I don't recall the site. If anyone knows the site for the refurbs could you post it here as I would not mind picking one up myself.

sub_junkie 08-04-09 04:00 PM

Re: 7.6 cu.ft Maelstrom- X 18" build
 

I would get the eQ.2, but it doesn't have the input voltage boost which I would need cause my receiver only puts out 1v for the pre-out channel

Thanks for the suggestion :T

sub_junkie 08-05-09 04:32 PM

Re: 7.6 cu.ft Maelstrom- X 18" build
 

Some more pictures. I have a feeling I am going to love how it will sound. :bigsmile:

http://i536.photobucket.com/albums/f...4/DSC01455.jpg

http://i536.photobucket.com/albums/f...4/DSC01457.jpg

http://i536.photobucket.com/albums/f...4/DSC01458.jpg

http://i536.photobucket.com/albums/f...4/DSC01459.jpg

That's my KLH 10" driver next to the Mal-X. Pretty big difference lol

http://i536.photobucket.com/albums/f...4/DSC01460.jpg





I am going over to my uncle's tonight and will hopefully have the box finished, except for the truck bed liner. More pictures to come then also :T

Thanks again for all of the help everyone

sub_junkie 08-06-09 06:50 PM

Re: 7.6 cu.ft Maelstrom- X 18" build
 

Finally got the box finished. It will be painted soon, just didn't have time last night as my uncle and I fnished it at 2 am.

Posting pictures in a litle bit.

The sound quality is awesome. I can' believe how low it goes. But, my current amp clips horribly at high volumes, and sounds like the driver is bottming out, but, of course it's not :bigsmile:
On Down 4 Tha Krown, is hits harder and lower than my brother in law's truck that has two Kicker COMP C10's on the Kicker 200.2 amp. His can go louder than mine right now, but it's becuase my amp clips up loud.
Quick question; I have 2 inch thick Egg Crate foam grey colored, and was wondering if it is open cell or closed. When I pore water on it, it just absorbs it like a sponge, but if I take off about an inch of thickness, it goes right through it. Does this mean that it is open cell?

Thanks


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