Box help for 18" Nightshade

[Slammer 10+ year member]

I have an 18" Nightshade on the way, and will be putting it in my GMC truck. I checked at Sundown, and Jacob recommends 4.0-5.0 cf vented. I want to get loud with this (running at 1ohm on SAZ1500), but still want some SQ without the box getting too big. Here is what I am thinking.......

20"wide, 18" tall, and 34" long

That gives me a gross volume of 5.74cf. The woofer displacement is .26, leaving me with a net of 5.48cf before port volume and bracing.

The sub must be upfiring, as it will be on a platform in the rear compartment of an extended cab truck. With this being the case, I am considering a slot port in one of the sides. I want to get to about 35hz with my tuning, but have yet to get on a port calculator. I am guessing that I will use 1.2-1.5cf for the port, with dimensions of 5"x16.5"x20" long (approximate).

I have run 15s for quite a while and have built several boxes for them ranging from 3.25 to 4.50cf net. First time with an 18, and would appreciate any insight. I know that the sound characteristics are quite diferent, and don't want to make a critical mistake in my box design.

Thanks!

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[basebalz13 10+ year member]

i loved my NS in 4 cubes...tuned to 32

 

[Slammer 10+ year member]

Yeh, 4.0 would be ideal, but I don't want to give up too much SQ, in my attempt to save space. You got good SQ with 4.0 @ 32?

 

[roarzorz 10+ year member]

I think the NS is one of the better sounding spl subs out there but it is definitely NOT an sq sub.

 

[basebalz13 10+ year member]

Yeh, 4.0 would be ideal, but I don't want to give up too much SQ, in my attempt to save space. You got good SQ with 4.0 @ 32?

For what the sub is, yes.

 

[on1wheel01 10+ year member]

I also have a 18 ns mine is in 4.8 cubes and sounds wicked. What part of nc u in im in mooresville just north of charlotte(if u need help with a box getting built).

 

[Slammer 10+ year member]

I am in Raleigh, but can do the box myself (once I get the sub and decide on a plan). Thanks for the offer though! I am gonna play around with a few calculators, aiming between 4.5 and 5.0cf and right around 35hz. Thanks for the input.