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Discussion Starter #1
I received my 18w6 and have all the sealed box specs. Wanted to know if anyone had seen a 4th order done for this sub. On other forums the 4th order specs given are all over the map. I cant find anything close to a consensus. Just wanted to see if anyone had seen it done real world and could give me an idea of the type of response.
 

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Quick model in bbpro using suggested optimum:

Ch1: 2.591cf
Ch2: 2.157cf
Vent: 6" dia x 15.16" length
F3: 22.53Hz
Fb: 41.67Hz

Give me some gross dimensions and I'll do a quick design for your space.
 

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If you went for a parallel tuned enclosure you'd be able to reduce the driver excursion-the 1st model I suggested would see it over excurt by a fraction at 23-26Hz.

Put a 4" dia x 21.08" port in the 2nd chamber to do this, vent velocity will get too high under 11Hz-unlikely to be an issue-but excursion will be fine to 13Hz or so.

Series tuned (vent from behind subwoofer into vented front chamber) would net near enough the same results.
 

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The 18w6 was designed for very small sealed enclosures. A correct bandpass design is almost impossible to build due to port size issues. Sealed 1.25 cu.ft was the recommended box. Ported designs were not recommended at all.
 

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The 18w6 was designed for very small sealed enclosures. A correct bandpass design is almost impossible to build due to port size issues. Sealed 1.25 cu.ft was the recommended box. Ported designs were not recommended at all.
It seems to model pretty well, group delay and phase issues were higher than the average, but port volume/length haven't caused me any issue in modelling the designs. Admitedly there is little gain in overal output when comparing sealed, vented or any of the BP models I have done (though if you did a 2.5cf vented tuned to 20Hz you get about 6dB gain at 50Hz compared to any of the others-but then ports become and issue as you'd suggest)

TL should work, BBpro won't model them, will try and model some stuff in hornresp if I get time/work out how;)

Box volume recommendations are just that-do they take into account the different vehicle the subs go in? JL also don't recommend the W6 or W7 are used IB-there's some peeps on here that'd disagree;)
 

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Sealed 1.25 cu.ft was the recommended box.
Are we talkin' about the original 18W6 circa late 90's early 2000's?

You are the last person I would question on this, but I've got a 15W6 with the original spec sheet and it lists all models 8-18.
8W6 - .375, .625 ported
10W6 - .625, 1.0 ported
12W6 - 1.25, 2.0 ported
15W6 - 1.25, 2.25 ported
18W6 - 1.75, N/R for ported
:confused:
 

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Curious on how this build will turn out.
 

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Wow, less than 2 cu.ft for an 18", that's small! I almost think I could fit that in my spare tire well. :D
 

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Are we talkin' about the original 18W6 circa late 90's early 2000's?

You are the last person I would question on this, but I've got a 15W6 with the original spec sheet and it lists all models 8-18.
8W6 - .375, .625 ported
10W6 - .625, 1.0 ported
12W6 - 1.25, 2.0 ported
15W6 - 1.25, 2.25 ported
18W6 - 1.75, N/R for ported
:confused:
The spec's I downloaded from the JL site list 1.75cf too
 

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Baron,

what power levels are you modeling this under for those port specs?
 

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Discussion Starter #15
Yeah I have been kicking around the idea to see if a 4th order gave any benefit over the 1.7 to 2.0 sealed that JL specs gave out. So it looks like a 4th order with around 4 cube for both the ported and sealed with possibly an exteral port could work? BTW, thanks Baron Groog for taking the time to model this up for me.
 

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Wow, less than 2 cu.ft for an 18", that's small! I almost think I could fit that in my spare tire well. :D
I've got 2 of them in my spare tire well...



I'm in the process of finishing up the trunk but they are up and running and sound phenomenal! I'm running each in 1.75 net with about 1100w on tap at 3ohms. They are very accurate and blend very nicely with my 3-way up front, and they can get very loud without losing control. I consider them one of the best sounding subs I've personally owned. Considering the mild advantages to other types of enclosures, I'm content with the performance from the JL recommended sealed enclosure volume.

Sent from my ADR6400L using Tapatalk
 

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I seriously think there's a market for a small box 18 like this. I really wish one of the smaller driver makers would step up and create one with a sub-200 dollar price tag.
 

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Here are the outputs.

Orange single tuned BP 4.865cf total volume, inc ports etc
Purple parallel tuned BP 5.038cf total
Yellow series tuned BP 5.089cf
Green sealed 1.75cf

Like I said, if you give the gross dimensions you have to play with I can model for that.

2nd image shows the group delay-not ever really played with BP designs but believe playing wwith volume and port can reduce it.
 

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How's this build going?
 
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