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Discussion Starter #1
I could use some help modeling this project. My pc took a digger and i can't find any free modeling software for my Mac.

I'm building two downfiring sonosubs with an Atlas 15 in each. I would like to use 20" tubes no taller than 52". I have four 4" Precision Ports from a previous build and their around 18" long. I'm shooting for a tuning frequency of 15 to 18 hz. I'm also going to build two matching sealed end tables, tube lengths not exceeding 22" with Atlas 15's in them as well. The 4ohm and 2ohm coils will be wired in series for 6ohms (more power handling), then wired parallel as a pair for 3ohm to the amp. Gonna be powering them with an EP4000/MIC 2200 combo that has been collecting dust for the past year. The top and bottom caps get gloss black paint, and my lovely lady is going to wrap them in a nice pomegranate basket weave leather. Any help would be appreciated!
 

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Discussion Starter #3
Thanks for the link. I will remember reading on a few different sites that it was ok to wire the two coils together for a 3 ohm load to increase power handling. If i recall correctly Chad (the designer) said it was ok. Kinda wondering about it now that I've read that.
 

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Discussion Starter #7
The leather we are wrapping it with is 54" tall, that leaves just enough for a hem on the top and bottom. There will be a little displacement for the rings that will be on the inside. I figured two on the top and bottom and two midspan depending on how round the tube is. Sometimes they stack them sky high and they get a little oblong.
 

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Discussion Starter #8
So the tube length doesn't include the legs. Could I fit the sub and one vent both on the bottom facing down if I used a 22" or 24" tube? I was originally planing to put the 4" vents on top.
 

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We'll do the ported first. A 20" diameter tube 52" long allows for 8.75 cu.ft. tuned to 20 hz with two 4" ports 17" long each. Power is 400 watts with a hi-pass filter at 18 hz to protect the driver from over excursion.

atlas 15.JPG

Here are the sonosub dimensions needed. The legs are 4.5" tall. Disregard the port dimensions as the program doesn't allow for dual ports.

sonosub atlas.JPG
 

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Discussion Starter #11
How low could i get with a 24" tube? I could use a single vent facing down which i would like. Thanks for helping me out!
 

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A 24" tube 52" high would allow for 12.9 cu.ft. Tuned to 18 hz power input is 400 watts with a hi-pass filter at 17 hz. You'd gain about 3 db from 20 hz down. Porting would be either a 6" diameter port 14" long or two 4" diameter ports 13" long each.

atlas 12.9.JPG

Here are the dimensions for a 24" tube, legs are 4.5" high.

sono 12.9.JPG
 

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Discussion Starter #15
Going to go with the 24" tube. Just returned from picking up four sheets of MDF. Price has really gone up!
 

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Discussion Starter #16
Is it possible to build a single large vented tube, tuned very low, with two subs in it? Or would i get more output out of two? Height and diameter wouldn't matter. I have an unused corner that would be perfect for it. Just bought a sectional couch, it's quite large and ate up some of my available space. Going to build two sealed tubes to go on the big screen wall, i was thinking around 4.5 cf each on those.
 

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Discussion Starter #18 (Edited)
So basically double the volume for an 18hz tune. My buddy just dropped off two 18" x 48" tubes for the sealed subs. I know their way to big for sealed but i wanted them that tall (54" finished height) for aesthetic reasons. Should i section them of at 4.5cf for sealed of can i tune them higher? These will be used mainly for music. The beast in the corner will be for HT.
 

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Discussion Starter #20
Are you using the low qts when your modeling this sub? Don't you own a few of these Atlas subs too? How do you think a small pair of higher tuned vented setups would sound for music? I have a pair of Atlas 12's in some sealed glassed boxes (2cf) in my car....their punchy and quick, but they don't play to low.
 
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