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Discussion Starter #1
Hi all,

Just registered with need for assistance in the dimensions of a DIY subwoofer. I have 2 x Elemental Design 13KV Dual 4 ohm subs (12 inch) with an ED 550 4 ohm plate amp. This will go into a small bedroom that has a Denon receiver (85x7) to power ED 6 inch MTM on stands. This will be used for 70% XM and 30 % HT.

ED built box will be 450 plus shipping, out of my budget. I can put together simpe square/rectangular design.

1. I am looking for a dual sub slot ported design with amp in the back.
2. Looking for response to 25 Hz, fast response for music, but does not overkill the front stage.
3. Design specific as I have no experience with the online design program nor the parameters.
a. Down firing with side firing port same side as amp, port above amp, rectangular in shape, for corner loading.
b. Down firing with down firing port with amp on side for corner loading, rectangular in shape.
c. Forward facing, one on top of another, with port at the bottom, rectangular in shape (vertically for space considerations) with amp in back on lower part (may interfere with L shape port.

Any help would be appreciated. I am a little fuzzy on port length and how to determine. Box will be built out of 5/8 MDF and spray painted with a textured paint of some kind due to costs.

victor
 

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Discussion Starter #3
Yes, not to their box design but in general for generic box building. I believe it was either 4 or 6 cubic feet (I believe 6) with 45 square inches of port.

3/4 or 5/8 MDF with the front baffle doubled up and a possible internal brace if my woodworking skills are up to it.

I think Home Depot or Lowes in my area may or may not carry 1 inch MDF

Victor
 

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Discussion Starter #5
Thanks for any help in advance. Its under ED website,left side, Help, Product Archive, 3/4 way down, 13kv2, specifications

Unable to post links under 5 posts

victor
 

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This would be the optimum size for HT and music, shown with 550 watts input power, with 2 subs wired for 4 ohms. The original E.D. plate amps didn't have a Hi-Pass filter, I'm not sure if the new version does or not, or which version of the amp you have. If the box size is too big we can go smaller but you'll give up low end output.

13Kv.2.JPG
 

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Discussion Starter #7
8.5 to 9.0 ft3 seems OK. I crunched some sealed numbers so I am looking at 2 x 11 inch cutouts, +1 in flange on each, plus 3 in between subs and side so around 33/34 in length (2.8ft) . Width is an 11 inch cutout plus 1 in flange plus 3 in per side distance from side so 18 in width (1.5). Height .... to make it work, looks like 2.14ft or about 25 inches plus spikes ( a little tall) for outside dimensions not including material, how to add port, internal brace, or driver displacement.

I can use this dimension for either corner loading with port/amp facing a corner/wall or the vertical option with amp in back and port facing forward under drivers.

I am actually wondering if I can lift the bed with blocks and put a large flat box under the bed.

I have no google sketchup skills.
 

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Discussion Starter #9
1. Does the port have to be L shaped or since the length of the port is smaller than the length of the enclosure, just part of the enclosure.
2. Any design help or program I can get cut sheet from? The port width is less than the enclosure width so I would have to create an internal "port" surround.
3. I do have access to lots of 6 inch pvc. Will creating single/dual 6 inch round ports that can be supported by an internal brace help.
4. I would actually like to start this this weekend or have a local car audio shop build it. With 8.5 to 9.0 ft3, what is the port volume I am looking at?

victor
 

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1. It doesn't have to be L shaped, just as long as the port entrance is 4 inches away from any wall.

2. There's an Enclosure Calculators here:

http://www.hometheatershack.com/forums/enclosure-volume-calculator/

It will give you the panel sizes and you can figure out how to best place them on a 4' x 8' sheet of MDF.

3. With this setup, since the amp has no Hi-pass filter, the sub will start to bottom out below 16 hz if pushed hard. If you were to get an E.D. eQ.2 and add a HPF at 18 hz, the air speed would drop low enough that you could use a 6" PVC port 17 inches long and also protect your subs from over excursion. Without a HPF the air speed would be 35 m/s which is too high.

4. Go with 9.0 ft3 net volume. Which port volume are you referring to, the slot port or the 6" PVC?
 

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Discussion Starter #11
Thats the link I needed for box help. Thank you. Now, its getting hard to work the numbers (9 ft3)trying to stay within my parameters. The enclosure will go againts a bedroom wall and most bedrooms only have so much flat wall space before you run into the bed, closet, bathroom door, bedroom door, or tables. I am trying to keep it against the wall within the 18 inches of depth and the 34 inch length. That said, it may be really, really, tall. Working the internal brace dimensions and brace cutout(s) brought out paper and pencil....then I found the circular brace cutout formula ( I have hole saws)...much better.

I may look into the 6 inch pvc option with a small brace set up in half moon to support the bottom of the tube and a similar brace on the opposing side.

victor
 

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Discussion Starter #12
thanks for all the help.

I believe I will be unable to create an appropriate vented enclosure for a small bedroom that stays in the 9ft3 dimension without becoming more problems than its worth. I believe I can stay with a small sealed enclosure that is easier to build and do not need the extra volume that a vented enclosure will provide.


thanks again for the help and the link. I will post when it is completed
 

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Discussion Starter #14
Going back to the ED website its showing (under archived data) shows.:

Spec 13Kv.2 Subwoofer
Sealed ( small ) 0.7ft³
Sealed ( ideal ) 1.0ft³
Sealed ( large ) 1.2ft³
Vented ( ideal ) 1.5ft³ Tuned to 30Hz
Vented ( DDLoud) 1.8ft³ Tuned to 35Hz

Based on suggestions from Mike P., WinISD shows 9FT3 to be optimum, but that box is too large to fit in a small bedroom.

I have no WinISD skills but I am learning. I added a Pe factor of 100 watts (ED shows 100/500), running 2 drivers in a vented enclosure and it came out to 4.789ft3. I ran to the vent tab and added a 6 inch (5.51 in) round port and it shows only 12.71 inches length and a Mach of .07. Now this seems ideal but....did I do something wrong in calculations as compared to Mike P.

If I go sealed and keep it against a wall, I would like to keep it at a depth of 18 so I dont kick it at night and make it down firing, height of 24, and whatever length is optimal (this allows for plate amp at one end). If I go vertical then it just stands up with amp on the bottom rear toward the wall and drivers facing forward.

Drivers are dual 4 ohm so I am planning to go 8 and 8 to run a 4 ohm to the amp and keep the amps 550 watts at 4 ohm.

EDIT
OK, just found how to adjust graph by using mouse and I could get really loud in 22ft3. Can I survive in the low 5-6ft3 range without overpowing the MTMs in a bedroom.
 

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Sealed ( small ) 0.7ft³
Sealed ( ideal ) 1.0ft³
Sealed ( large ) 1.2ft³
Vented ( ideal ) 1.5ft³ Tuned to 30Hz
Vented ( DDLoud) 1.8ft³ Tuned to 35Hz
The above recommendations are for car audio where the extreme effects of cabin gain are taken into account. Those recommendations do not apply to in home use where room gain is much less.

If 9 cu.ft is too big then what is the biggest box size that is acceptable to you?
 

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Discussion Starter #16
Largest acceptable enclosure for down firing, side porting above amp, running length of a wall with ports facing a corner

18 inches width ( covers the 11 inch cutout/12 inch diameter speaker/ 3 inches per side for support)
18 inches height (keeps it low to the floor, allows for amp mount of 8x8 coutout and 10x10 flange, and possibly dual 6 inch ports above the amp)
36 inches length ( allows for 2 x 11 inch cutouts/ 12 inch diameter speakers/ 3 inches inbetween speakers for support.

I can make it wider if the ports go vertically on the side of the enclosure next to the amp a la svs design.

If it is vertical with subs on top of each other and port on the bottom, then I would like 16 width x 16 depth, and height is not an issue, but under 48 inches as it would have a very small footprint .
 
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