It would only make them louder if you used a peice of pvc for the port, or a aero port. The problem will be that your box is going to be fairly small seeings it is a sealed enclosure. What are you current box dimensions?
Car - 99 Neon Sport
Batt - 1 Redtop up front 200amp EA Alt
Sub - 2 10" Kicker L7's in ~4.5 cuft @ 38hz each on a Xtant X1001
Front Highs/Mids - JVC CS-FS6 on Xtant A2002
Rear Highs/Mids - Not hooked up
HU - Pioneer DEH-P8600MP
1/0 wire ran thru entire car aswell as big3
DB - 139.2 @ Headrest 143.3 @ Dash
How Many drivers do you have?
Are they divided in the enclosure?
How Thick is the Board this box is built with?
And as far as port placement goes... As many as i have heard. Where you put it really doesn't matter (as long as it's Not Suffocated, (like On the bottom of the Box Facing down))... In My Greater opinion though, if you have it in a trunk it's better to have the port Facing Toward the trunk or on top of the Box (not toward the sides because the reflect eachother and really messes up the phaseing) And not on the Back of the box because that really takes away pressure if i remember correctly.
Well, you have Appox. 1.7 Cu. Ft. So that's not too small for a ported Enclosure. If your on a tight budget I would go with Pvc Pipe, it's Cheap, Easy to work with and VERY effective. Are you wanting to port them for Sound Quality, Pure SPL, or a sort of even mix? By the sound of you wanting them "Louder, I'm Guessin you're Probably leaning toward SPL but want some sound quality in there too. If i were you i'd Probably tune to 38Hz. (But that's Just my opinion, Don't take my Word for it.). What sounds good to some, May sound bad to others.....
What Size of PvC pipe are you Planning on Useing? 3 Inch? 6 Inch?
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