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Sundown Audio X12 V2 - Enclosure Feedback Request


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Hey everyone,

 

I am planning a build in my 2010 Honda Crosstour and have worked up a design using the max dimensions that I'd like to try to stick to. I am looking at picking up one of the D4S JP23's and running at 1-ohm. Stock alternator - Big 3, Deka 9a34 underhood and Deka 9a31 in the rear for reserve. With stock alternator, I do not see the benefit of trying to drop to 0.5-ohm. Would love the extra power, but hoping this will be enough at 1-ohm in this space for this subwoofer.

 

With space constraints, I'd like to steer towards an aeroport. In doing research I was having a bit of trouble finding suggestions on using an aeroport in regards to port area for this subwoofer. It seems with slot port designs, the consensus was around running port area on the higher side. Example: 40in^2 for 2.5ft^2 --> 16in^2 per ft^3. I'm aware that calculating per ft^3 isn't a rule, but I tried to translate that to basic aeroport rules I'm familiar with and using a 6" aeroport in 2.5ft^3, I came up with around 11in^2 per ft^3 which in the past for me has seemed to be the upper end of general aeroport port ratio on recommendations.

 

I do not have much experience with the Sundown X-Series specifically, so I am wide open to feedback or suggestions.

 

Net Volume: 2.54ft^3

Tuning Frequency: 32.21Hz

Port Area: 28.26in^2

Port Area Per Foot: 11.13in^2

Sundown X12 V2 Enclosure SketchUp.JPG

1997 Chevrolet Cavalier Two 12" DC Audio XL M2'sCrescendo Audio BC5500d

Current Scores: 150+ out the Trunk

On 6/30/2011 at 1:11 AM, 'Ray' said:

Acoustical energy is free. Electrical energy is not.

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8 or 10 inch aero.

https://www.bigass-ports.com/

Also I am hoping that the big tub for the subwoofer is just a mistake, you really wouldn't want a tube around the woofer inside a box, unless and only unless you have a massive enclosure or wall with multiple woofers and you are having crazy unloading issues. On a single sub enclosure that would never be a problem and will cause efficiency issues more than likely and hinder box performance.

 

 

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If I increase my enclosure size to net 2.5ft^3 with an 8" aeroport, that gives me ~ 50in^2 of port area/19.24in^2 per ft^3. I'd have to bend the port twice to fit it in the enclosure, which will be it's own battle. Does this sound closer to what a single X12 would like?

 

I'm only questioning because that's more port area than the suggested slot port. And with aeroports being more efficient than slot ports, I'm concerned with that much port area I may run into unloading issues and an incredibly narrow frequency response. (My past experience with that much port area on my DC Audio XL's, also understanding that those are completely different subs than the Sundown X's.)

 

Also, that big tub was just me dragging the cutout down in Sketchup to make sure I had motor clearance above the port. I wouldn't be putting a tube around the sub in the box. 🙂

X12 V2 8 Inch Aero-ImResizer.jpg

1997 Chevrolet Cavalier Two 12" DC Audio XL M2'sCrescendo Audio BC5500d

Current Scores: 150+ out the Trunk

On 6/30/2011 at 1:11 AM, 'Ray' said:

Acoustical energy is free. Electrical energy is not.

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I think going to a slot port will allow you to get the port area you need and length of port to fit the box.

 

@audiofanaticzdoes have the port area at would be considered the optimal based on the amp you're looking at. I think you can reduce the size of the port area to make it work for your application without sacrificing too much. 

 

The "problem" with going Aeroports is the ability to get the length required once you're past the 23-24" in length that they are sold in. The other "problem" is there's a big jump between port area from 6" to 8" to a 10" port. You can create any port area going with the slot port.

 

 

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12 hours ago, Cashdollar2009 said:

If I increase my enclosure size to net 2.5ft^3 with an 8" aeroport, that gives me ~ 50in^2 of port area/19.24in^2 per ft^3. I'd have to bend the port twice to fit it in the enclosure, which will be it's own battle. Does this sound closer to what a single X12 would like?

 

I'm only questioning because that's more port area than the suggested slot port. And with aeroports being more efficient than slot ports, I'm concerned with that much port area I may run into unloading issues and an incredibly narrow frequency response. (My past experience with that much port area on my DC Audio XL's, also understanding that those are completely different subs than the Sundown X's.)

 

Also, that big tub was just me dragging the cutout down in Sketchup to make sure I had motor clearance above the port. I wouldn't be putting a tube around the sub in the box. 🙂

 

 

Actually it is when you oversize your box that you get a peaky response, that will be the main reason and this just help the sub to reach it's mechanical limits on less power.

 

Quite frankly in your case I would just do a slot port and be done with it, if you do an 8" round port the box will end up bigger than a correctly designed slot port box.

 

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Another option for a port is doing an "octoport", but it will be more work and take more time to build it compared to a typical slot port.
However you kind of get the best of both worlds in a sense because you're able to dial in the exact amount of port area that is wanted/needed like you do with a slot port, and since the port is more less rounder like an aero/tube port you have less inner port wall which means less surface tension for the air to pass over which is part of the reason round ports like aeros can be more efficient when used properly.
Plus octoports can look cool when done right even though performance should always come before looks.

 

 

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I really appreciate your input on this guys, I am seeing what you are saying.

 

I'm settled on sub-up orientation. The challenge with port orientation is that I only have about 6" of clearance on the side for a side exit without the wheel well blocking the opening. (Why 6" aero barely fit, and why I couldn't do a side firing along the bottom to the side making the slot port width equal to the depth.

 

Next idea for a slot was exiting the back, which is probably a more ideal port application in my scenario anyway. The challenge here is that there is not enough box depth to make it around the back side of the box without hitting the sub.

 

Would you feel it would be more efficient to have the port exit in the bottom back right and just snake it around a couple bends to get my port length? Or something similar to the SketchUp model I created here where it starts with the 7.5" width and cuts down to 3.25" starting at T?

 

1997 Chevrolet Cavalier Two 12" DC Audio XL M2'sCrescendo Audio BC5500d

Current Scores: 150+ out the Trunk

On 6/30/2011 at 1:11 AM, 'Ray' said:

Acoustical energy is free. Electrical energy is not.

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Okay update...

 

After using Triticum's Port Calculator to find min/optimal, I then played around in Torres Calc to see how close I could both actually fit the length needed and then have my total port length below the 44" suggestion, then modeled it into WinISD to check port velocity.

 

Net Volume: 2.60 ft^3

Tuning Frequency: 32.34 Hz

Port Area: 48.75 in^2

Port Area/Ft^3: 18.74 in^2 (Did not base target off of this, focused on total port area for the space, leaving for reference if anyone cares.)

 

I have just under 1" of clearance below the pole vent and the top of the port.

 

All images to information referenced above in imgur link, cannot upload images directly to forum:

https://imgur.com/a/YsstATP

1997 Chevrolet Cavalier Two 12" DC Audio XL M2'sCrescendo Audio BC5500d

Current Scores: 150+ out the Trunk

On 6/30/2011 at 1:11 AM, 'Ray' said:

Acoustical energy is free. Electrical energy is not.

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So back to the side firing with a round/aero/octo port if your port diameter is 6 inches, then you will want the space between the outside of your box and your wheel well to be at least half that which would be 3 inches. 8 inch port then 4 inches between the box and wheel well and so on. So if you have 6 inches between the box and wheel well you would be set to run up to a 12 inch diameter port theoretically, now by no means am I saying you need a 12 inch port I'm just giving you a basic guideline to work with because there's a lot of other things that can change things too.

 

Typically sub up port back is always the go to for suv's, hatchback's, van's, and other open cargo area vehicles in musical applications. Now having the port opening in the middle of the back of the box, along the bottom of the back of the box, or on one side or another of the back of the box can change outcomes as well. Now as far as which is better or will be louder there's no real way to answer that except build a box of every variation and test, but again since this is a musical application and not something that goes burrrrrrp for 5 seconds that is rather wasteful to do because those few tenths of a db to even a full db that one way could be louder compared to another won't be audible to your ear.

 

That being said, I hate having to wrap a port around a box and put more bends in it than needed, I also hate splitting a port like that even more then put more bends in it.
Whenever I do a slot port I will have the port run either the full height or full width of the box unless the port area needed is so little that It wouldn't be practical being a something silly narrow like 1/2 or 3/4 inch wide, and thats when I would move over to an aeroport or even just a piece of pvc. That being said if your run the port along the full width or full height of the box and use 3 of the exterior box walls as part of your port walls you can usually make the port narrower while still getting the port area you're after and potentially not run into clearance issues with the woofer.

Now like I think I said in my other post, put performance before looks, this is what is screwing your royally right now because it appears that your heart is set on having the sub in the center of the box and the port in the center of the box and due to that performance is going to take a huge hit one way or another.

So these are options I would look in to exploring, and if it was me I would be using the box I circled in yellow and not worry about the woofer/port being centered in the box especially when your running in to clearance issues to get desired port area. 

Like I said performance > symmetrical looks, especially when those looks can cause you potentially a couple db of output!
Now these aint all square and to size ratio etc, I don't got time to sketch up designs, so quick basic MS Paint illustrations is all you get, and you can do all the number crunching and drawing to scale to see if any of these will work best for you, but like I said the one circled in yellow will most likely be your best bet.
Box 1 port along the entire bottom width.

Box 2 port along the side the full height of the box.

box 3 port along the entire side height, but then bends 180 degrees along side itself and this can be repeated back and forth as needed.
box 4 triangle port in the corner of the box, can bend it up as needed to get port length for tuning.

box 5 triangle port same concept as 4 but one in each corner to get more port area, and then again bend it up for port length to get desired tuning.

box 6 sub location on the left side of the box to give adequate room for port area/length, port along the side of the box the full height of the box, and bent to get desired port length for tuning, and if wanted/needed you could fold the port along side itself like in Box 3 instead of making an L shaped port. Like I said crunch the numbers, draw it up this box will be your best bet.

ewergfsdbvc.jpg

 

 

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12 hours ago, Cashdollar2009 said:

Okay update...

 

After using Triticum's Port Calculator to find min/optimal, I then played around in Torres Calc to see how close I could both actually fit the length needed and then have my total port length below the 44" suggestion, then modeled it into WinISD to check port velocity.

 

Net Volume: 2.60 ft^3

Tuning Frequency: 32.34 Hz

Port Area: 48.75 in^2

Port Area/Ft^3: 18.74 in^2 (Did not base target off of this, focused on total port area for the space, leaving for reference if anyone cares.)

 

I have just under 1" of clearance below the pole vent and the top of the port.

 

All images to information referenced above in imgur link, cannot upload images directly to forum:

https://imgur.com/a/YsstATP

 

Here is a simple design alternative, the sub can be mounted on top and it can be done with your available dimensions:

 

NOTE: no need for multiple port turns or high build complexity.

 

NOTE:  Maximized port area as possible to above 44 square inches which is above and beyond of what is needed for this sub in 2300W,

 

TOP VIEW:

 

top.png

 

 

lst.png

 

 

 

 

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