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Discussion Starter #1 (Edited)
I started on 2 of these yesterday. I thought using the flared ports would be quicker but my assumption was wrong. Setting up and gluing is a pain , the connectors are wonky and have to be forced on which makes fitting a mugg. I understand why Mark got custom lengths to eliminate a glue joint and fitting.

I was really hoping to have both of these done today but as they say experience is something you get right after you need it. I also shorted myself a connector:rolleyes:. End of the tunnel, should have one running by end of day tomorrow .

Update 9/15: 2nd batch of connectors and port went together quite easily. I can only guess the first shipment may have been at the bottom of a pile and distorted.
 

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Is that "The U" in your profile pick? If so, all this makes sense now. My Bayou Bengals kicked your butt, Flared ports kicked your butt....you're gonna be sore for a while:p
Seriously, what is the size of the cab and tune? Can't wait to hear your impressions.
 

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Nice job on the enclosure. What tuning?

I was never a fan of slot ports but, after building one and being around it more flared ports just look off to me.
 

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Discussion Starter #4
Thanks for rehashing the LSU game, I had just gotten past it:p

Enclosure is 36x32x24, its a few inches deeper then the WW speaker cabinet Mark Sent Josh to test with the 21ds115.
Tuning was at 19hz and was 14.5hz with a port plugged. Mark was kind enough to help with port length, proximity to rear wall and dsp.

These ports are definitely freakish in person. Building 2, and waiting to see if more are necessary
 

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So is rear port velocity kept in check with a port being plugged?
 

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Discussion Starter #6
This a a quote from Josh's test

" even with only a single 6 inch vent open the output compression and amount of air noise through the port was not excessive. I’d consider it to be quite useful in this configuration. The burst output testing confirmed that the lower single vent tuning allows notable output down to the 12.5Hz band. In rooms imparting significant lift to the lowest bass frequencies, or those requiring slightly less than maximum output from the X21, this type of steeper response roll off down to a deeper frequency may match up quite well for HT. "
https://data-bass.com/data?page=system&id=144
 

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Discussion Starter #7
After getting some sleep, I remembered when the flare kits came with the connecting rings on the flares. I noticed they were the easier connections to mate. The extra port and connectors were in separate boxes, if anyone uses these I would recommend putting the connectors on the ports and leaving them on until installation, just a assumption but they are the same pieces.

Initial impressions are good, i need the other one hooked up so I didnt do any measurements, just loaded in Marks settings and put in JW and a few others.
 

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Subbed....What are you using to power these beast ?
 

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Discussion Starter #9
A sp4000 is the amp. I have noticed some cabinet resonance coming from the top and bottom panels so I am adding some U braces to cover the planes. Nothing major but it was noticeable at spirited levels.

Mark used mdf and my cab is longer and I used plywood. I noticed my braces have a tad give in the middle so Im sure thats contributing. Worst case Ill laminate some mdf to the exterior and make it all 1 1/2"
 

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I have noticed some cabinet resonance coming from the top and bottom panels so I am adding some U braces to cover the planes. Nothing major but it was noticeable at spirited levels.
Can you describe the resonating sound you experienced?
 

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A sp4000 is the amp. I have noticed some cabinet resonance coming from the top and bottom panels so I am adding some U braces to cover the planes. Nothing major but it was noticeable at spirited levels.

Mark used mdf and my cab is longer and I used plywood. I noticed my braces have a tad give in the middle so Im sure thats contributing. Worst case Ill laminate some mdf to the exterior and make it all 1 1/2"
Did you have any kind of lining in the cabinet? I see even Mark uses it in his enclosures and I wonder if adding some would make an audible difference vs adding another layer of MDF. I know I can hear a difference adding lining to a subwoofer cabinet vs unlined but I see many people are against it or they do not think it makes any audible difference. https://data-bass.com/images/systems/144/slides/x21 915.jpg
 

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Discussion Starter #12
Low level hum, can feel it on the top . There is no bracing front to back on the top, the sides have bracing and dont exhibit the same feel.

After scrutinizing Marks cabinet pics I noticed I did not put in braces on the top:eek: Hard to see on his site and databass has denim covering the braces so I only feel slightly embarassed, should have put more thought in but I banged these out quickly. Easy enough to add

I made these off pics, I tried to keep as close to them as possible He was gracious enough to help with port setup. After seeing I missed braces Im not sweating it.
 

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Discussion Starter #13
Did you have any kind of lining in the cabinet? I see even Mark uses it in his enclosures and I wonder if adding some would make an audible difference vs adding another layer of MDF. I know I can hear a difference adding lining to a subwoofer cabinet vs unlined but I see many people are against it or they do not think it makes any audible difference. https://data-bass.com/images/systems/144/slides/x21 915.jpg

I added lining as he did, in between ports on the top and down the back to the first brace. Im still waiting a connecting ring to finish other cab. Ill be getting other braces cut some time during the week and put them in.
 

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Discussion Starter #14 (Edited)
Couple of braces on top solved my issue. Quite impressed how hard 2 of these pound across the board. Both ports open tuning came in 16hz. I haven't even tried plugging a port, all things equal should be around 12hz. I just wanted to get them setup and running and watch some movies. BvS is killing it right now.

My only regret is I didnt have the time or energy to do the other 2, sold them and my other sp4000 to a friend. Not sure i need 2 more but when I get some free time in late winter Ill be doing 2 more for the rear.

I had been thinking of running my IB with these, I dont see the point at the moment, they sound great by themselves and beat the 4 18's handily. Worth the money
Before they landed behind the screen
 

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Where did you get your ports from again?

Was looking at using my pair of 21's in a similar build and really love the look of these ports. I have built layered MDF ports in the past but curious what these will cost me. And was also looking at using the SP plate amps also if everything goes well.
 

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Where did you get your ports from again?

Was looking at using my pair of 21's in a similar build and really love the look of these ports. I have built layered MDF ports in the past but curious what these will cost me. And was also looking at using the SP plate amps also if everything goes well.
If hes using precision port, they have a website with good info and links to authorized retailers.


http://www.psp-inc.com/
 

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The ports came from parts express, you can buy individually or buy a kit with 2 ports, 2 rings, 2 12"tubes. I think it was
$240 for all 4 ports completed. The manufacturer is Precision Ports. The sp1 runs 2 drivers quite well if you are using the B&C's
Thanks. I have a pair of 21SW152's thats been sitting on a shelf for quite a while so thats what I will be using. Was looking at building this design anyways but really liked Mark's cabinet design when he posted it a while back. So thats what I was looking at building same as yourself.
 

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Discussion Starter #19 (Edited)
I almost bought the 21sw152 in case I wasnt fully satisfied and wanted the othorns. Im happy to say I dont regret the purchase, they exceeded my expectations. I cant believe the difference in the waterfall from my previous subs except for 20hz everything is well under 300ms and most of it is under 200ms. They were dbl the xmax but these have plenty of tactile response in comparison. They were easy to blend in with my mains in comparison to my other subs.

Besides adding 2 more later I wont be chasing another driver in the future. Look forward to seeing your build

I lied
 

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Couple of braces on top solved my issue. Quite impressed how hard 2 of these pound across the board. Both ports open tuning came in 16hz. I haven't even tried plugging a port, all things equal should be around 12hz. I just wanted to get them setup and running and watch some movies. BvS is killing it right now.

My only regret is I didnt have the time or energy to do the other 2, sold them and my other sp4000 to a friend. Not sure i need 2 more but when I get some free time in late winter Ill be doing 2 more for the rear.

I had been thinking of running my IB with these, I dont see the point at the moment, they sound great by themselves and beat the 4 18's handily. Worth the money
Before they landed behind the screen
Thanks for directing me here from the Dev thread! Really nice job! Man this looks like just what I've been searching for. The graphs you posted in regard to my questions on the Devastator thread...those were with the 12hz tune, one port plugged? I know so much is setup and room dependent, just trying to get an idea. I'll alter my cabs a bit as well, but trying to keep with the overall volume here and a variable tune that comes in close on both ends..16, 17 and 12 or 13 to see what works best in the end for me. I will shrink the depth on mine and add it in height and or width. My room is 25 feet deep before the screen wall, so I want to keep that false wall as shallow as possible. I was going to keep it simple and but GSG full Marty packs, but I think building something like this with a variable leaves me with more options.
 
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