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7.6 cu.ft Maelstrom- X 18" build

72K views 304 replies 22 participants last post by  japperrrr 
#1 · (Edited)
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:



The cut outs ready for nailing and gluing:





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



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:





Roundover on the top of the port:



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.



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







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:
 
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#63 · (Edited)
Edit: I meant that sucks to Sub_crazy :bigsmile:
I didn't mean the movie part Mike. Sorry for the confusion :T


That sucks.
I have noticed that it sounds like the driver is bottoming out while listening to regular music. How can this be happening? The amp isn't clipping, and it doesn't look like the sub is at 33mm, but it sound like it. I have the HPF set at a minimum of 12hz, and there shouldn't be any bass below what sounds like 20hz. I especially noticed it while playing Throw It Up Chopped And Screwed. My mains were set at -7dB, and the receiver is set at 62dB. The sub channel was set at 0dB. I have the gain all the way up on the EP2500, and the output on the MIC2200 is in between 0dB and +8dB, so I'm guessing it's set around +4dB or so. Should the sub be louder that what it is with the gain and everything how it is?
 
#64 ·
I think that vicious circle of upgrading has begun... :dumbcrazy:

What would be the optimum box size for a dual 18" PR'd Mal-X? I'm mostly just curious, but can't get it to model it right. If it looks much much better on the low end (not that I really need more...) I might just get a few PR's from Kevin in a few months :thud:
I would like to model it in my program, so if someone models it, could I get all the specs like the weight added, etc...? I can get the PR's specs though haha.
I just don't know how to compare a PR'd box compared to the ported on I already have according to WinISD. I just can't seem to get it right.
 
#66 ·
I had heard that it was 6hz, and 11hz tones in it. But, who knows. I will try a 11hz test tone if I get a chance to see if it compares to the one in the song. I will try lower test tones also to see which one compares the best to the 6hz or 8hz tone. Would there be a program that can tell you what the bass tones in a song is?
 
#69 ·
Mike P. would have a better idea if it is worth it but I don't think you will gain anything by going the PR route over your large ported enclosure. The only gain you will get is a smaller enclosure. The extra money would be better spent on another Mal-X if you can shoe horn it in.
 
#73 ·
Generally there two really common causes of hum with this setup:
  • Cable TV that causes hum because of bad ground.
  • Good old ground loop from being on a different circuit.
  • Bad signal cable setup between the AVR and MIC2200, the 1/4" mono to RCA adapter, or anything that shorts the ring to sleeve or XLR pins 1&3 makes it easier to get noise.
You should try to fix any grounding issue if at all possible.

Un-hook any cable feed and or HDMI to your AVR to see if the hum goes away.
Trying a power strip with CATV Coax "filtering" will also tell you if your cable feed is improperly grounded. If that works your cable feed has a bad ground most likely.

Run a nice heavy ground between the AVR and EP2500 if you've got a ground loop. But if that fixes it you should also look at having the electrical system in the house fixed because that's the real source of the problem.

You should always run balanced cable between the MIC2200 and EP2500. A Mic cable is the same as a balanced patch cable, both work correctly. This is not a fix for a ground loop but the correct way to connect the two.

If you are using a RCA adapter between the AVR and MIC2200, customize the cable with a balanced XLR on the MIC2200 end like so:

DO NOT connect the shield to signal - anywhere.
 
#74 ·
Here's the cables that I bought:

The cable going from the MIC2200 to the EP2500

http://www.bhphotovideo.com/bnh/controller/home?O=cart&A=details&Q=&sku=158365&is=REG

The cable from my receiver to the MIC2200

http://www.bhphotovideo.com/bnh/controller/home?O=cart&A=details&Q=&sku=133652&is=REG

The Behringer Tech had me dicsonnect the RCA cable going to the MIC2200, and the noise was still there. As soon as I turn off the MIC2200, and keept the EP2500 on, the noise goes away. He said that the hum issue could be from my cables, or needing a power conditioner. He also had me try a different outlet in my room, and the noise was still there.

Thanks for the help NEO. Is there any easy way to get a 14hz HPF or very close to it without using REW?
 
#75 ·
After listening more at high volumes, it appears the the driver is actually reaching or very close to its Xmax. There is definiely distorion; the MIC2200 is at 0dB at the max, and I have the gain on the EP2500 all the way up. The Output knob on the 2200 is at 0dB. I had my receiver at 65dB, the mains and surronds turned down to -10dB, and the Sub channel was set at +6dB. This is happening while listening to songs like Down 4 Tha Krown by Kottonmouth Kings, Throw It Up (Chopped and Screwed). The driver sound like it is bottoming out on the tones in Bass I Love You, except for the 6hz and 11hz tones suprisingly. So, it sounds like its hitting its limits on the 30hz and up tones. It shouldn't be doing that, right?
I also found a small cracked piece of drywall in the corner of the sub. :bigsmile:
It's very hard to see. I had to be very close the the corner of the wall to see it.

I found something very wrong with my computer... :gah:





That can't be good haha. I don't look at anything bad on my computer. (seriously)
 
#77 ·
I'm not necessarily happy about it, I just find it funny. I gotta get a SPL meter and see what the dB's are in my closet on the supposed 6hz and 11hz tone of Bass I Love You and the 16hz on The Bass Will Destroy You. It almost feels like your eardrums are going to explode. For some reason, the very low frequencies are magnified in there... It's awesome.
 
#80 ·
I had disonnected the Sub out RCA cable from the RCA to XLR cable going to the MIC2200, but I haven't disconnected the RCA to XLR cable from the 2200.

I just disconnected the Sub out RCA from the one going to the 2200, and the noise changed. I disconnected the input cable from the 2200, and the noise was gone. That means I have a bad RCA to XLR cable, right?

Thanks for solving my problem :T
 
#81 ·
I just called B&H Photo, and they are sending me a new cable for no charge. It's the same one, so hopefully that will solve the problem, and that the problem doesn't lie in the way the cord is made itself.
My 150w plate amp would put out less watts is 4ohm rather than 8ohm, correct?
 
#82 ·
I'd be surprised if the new cable were any different than the one you already have. But hey, at least they were nice enough to ship you out one for free. Brownie points for good customer service. You can re-terminate the cable and fix the problem if you can solder. If you can't solder I can make you a cable, but that's not free:spend::R Out of curiosity what AVR are you using in your setup?
 
#83 · (Edited)
I can solder if needed :bigsmile: Sometimes it's not the neatest job, but it definitely works. Thanks for the offer too :T

I'm using a cheap Insignia 500w 5.1 channel receiver. I'm looking to upgrade it down the line, but it migh be a while. My dad thinks that now that I upgraded the sub I don't need to do anything else. :huh:
But, I have to do what he says, so it might be the end of upgrading for a while. But, there is always birthday's and Christmas'... haha

So you think that the problem lies in the cable not having the correct grounding (I guess, if you want to call it that...cause I don't know)
 
#85 ·
I think it would be a good idea for you to sit and watch while playing various things for a while so you get a good idea of how much output you get and where your excursion is at doing so. maybe some sweeps too to get an idea on frequency:excursion. Once you get a good image in your head, you'll have an idea just from output and sound to know when you might be nearing limits.
 
#86 ·
That's what I have been doing. Whenever I hook up a new amp to something like my old subs, I would watch it, see wha it was doing at whatever volume, and try to remember that that is all I could get out of it. Either way, the Mal-X should be able to overpower my front speakers when they are set a -7 to -10dB and the volume on the receiver is at 70dB, right? Could it just be near its Xmax due to the MIC2200 boosting the pre-out voltage so much? My receiver's sub channel is set at 0-+5dB, and the 2200 is usually set at the same, and the gain is all of the way up on the EP2500.

Either way, I'm extremely happy with my new sub :T
 
#87 · (Edited)
what I have learned from experience is ignore settings. it is all about what is actually happening. wattage. clipping. frequency.

"so and so had his deck only 1/4 the way up and his gains only 1/2 and it was so loud! I can't wait till he turns the gain all the way up and turns his deck all the way up! It will be so amazing it will blow his windows out and you will hear it 2 miles away!"

settings don't mean much. the RMS your sub is getting is what matters, and at what frequencies. I'll bet you could give it full power from 60Hz on up in bursts with no worries. Try playing full power 20-30Hz above tuning or, I don't remember what you got going on for SSF, but 10Hz below tuning.... all of that stuff means much more. (EDIT don't actually do that! lol. I guess if you're careful, you can try it while watching it but start the volume low and see how high you can turn it before it really starts moving along... will learn a lot)

My first big mistake once I started properly porting, was I didn't realize that when I tuned below 20Hz, excursion becomes a problem in the 30s.... I didn't realize the port stopped helping with excursion above tuning. That was a long time ago. I've learned from my mistakes, and I still am. Hmmm... I wonder what I'm gonna break next.... hahahaha
 
#88 ·
what I have learned from experience is ignore settings. it is all about what is actually happening. wattage. clipping. frequency.

"so and so had his deck only 1/4 the way up and his gains only 1/2 and it was so loud! I can't wait till he turns the gain all the way up and turns his deck all the way up! It will be so amazing it will blow his windows out and you will hear it 2 miles away!"
settings don't mean much. the RMS your sub is getting is what matters, and at what frequencies. I'll bet you could give it full power from 60Hz on up in bursts with no worries. Try playing full power 20-30Hz above tuning or, I don't remember what you got going on for SSF, but 10Hz below tuning.... all of that stuff means much more. (EDIT don't actually do that! lol. I guess if you're careful, you can try it while watching it but start the volume low and see how high you can turn it before it really starts moving along... will learn a lot)

My first big mistake once I started properly porting, was I didn't realize that when I tuned below 20Hz, excursion becomes a problem in the 30s.... I didn't realize the port stopped helping with excursion above tuning. That was a long time ago. I've learned from my mistakes, and I still am. Hmmm... I wonder what I'm gonna break next.... hahahaha
That almost sounds like what my dad said when I told him I wanted to order an 18" :T

Well, what is kinda weird is while listening to Bass I Love You by BassoTronics, the sub is nearing its Xmax (or what is looks like to me) on the most of the other higher tones besided the 6hz and the 11hz tones. It looks like that on the 30-40hz tones. I will try to take a video of it playing Bass I Love You, Throw It Up Chopped And Screwed, and see if you guys can tell me if it is nearing its Xmax or if its just distortion from other things, etc... But, I know it's hard to tell what stuff is doing when its not in person, but maybe someone can give me a guideline or something, possibly.

Thanks again for the help everyone.
 
#90 ·
Yes, I modeled quite a few things in WinISD. I found out that I would need to run a minumum of 3100w to make it reach its Xmax at 24.40hz. To reach it at 30hz, I would need 3600w. 40hz would need 6500w. All of these are asuming at 10hz HPF. Now, I know that the EP2500 can't put out anythig near those numbers, unless the EQ is jacking it up. I checked that in WinISD, and with running 1950w, the Xmax was at 37mm at 21hz. Anything above 27.48hz is in check with the Xmax. That is atill running at 10hz HPF.

There's no way that this problem can't be associated with my bad cable, right?

Thanks again for the help everyone. I really appreciate it.
 
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