Help with 2 18" Box design

[MrBalll]

Edit: new measurements in post 5.

Little background. I listen to Hip-Hop/Rap and the occasional Rock-n-Roll. When I listen to the Rock I plan to use a remote EQ to turn the subs way down or completely off. I currently drive an 04 Tahoe and I will have the port facing the lift gate and the subs facing upwards.

Ok, I have been trying to use the Speaker Box Tuning utility and I thought I had it all worked out but I can't get the port worked out.

I will hopefully have two AA 18" Chaos subs in a ported box.

Since this will be a daily driver I assume I want 40 Hz for the tuning?

This is what I have so far. The subs call for 6-10 CF each for ported so I figure after the port walls and sub displacement 18 CF should work out fine.

I assume that the front of the box does not count as a common wall so I only put two in there, top and bottom. Wasn't too sure on this part, but this is idea I have so far.

So, really all I need is an idea as to what I should tune it to as well as help filling in the middle and bottom section of the Tuning utility. So how long/wide I need to make the port walls and opening and if I even need those extra pieces that are behind the subs or if I just need a straight wall and that's it. If I do need those pieces behind the subs how long should they be?

Thanks for any help,

MrBalll

Edited February 25, 2011 by MrBalll

[THEKINGsBACK]

tuning is way to high... imo

[MrBalll]

See, that's one thing I still don't quite get is the tuning.

If I am going for both sound quality and a loud sound, more so quality, would I want to tune it to around 35 or 36?

[uhoh_45]

sub up port back

1 common wall

this is example of what you would like to see but not enough box for 2 18s

[MrBalll]

Thanks for the help, uhoh_45. If the problem is the box measurements I could go to 48" width x 34" depth and if really needed 26" height.

Would that make a big difference?

[uhoh_45]

plug in

25 h 46 W 34 D

port 5.25 H 44.5 W 16 long

1 common wall and sub up should leave you with s 16 cube box tuned to 35 hz

heres box

Edited February 25, 2011 by uhoh_45

[MrBalll]

Awesome, I appreciate it, uhoh. One more little question.

The width on the port is huge. So it would pretty much be your image only with a much longer port opening and subs upward? Would that cause any structure problem since it will basically be the entire length of that wall? Or will I just need to put one or two two inch long braces along that wall?

[uhoh_45]

your worried bout the port being so big that it will flex n shit? or what

if it was me doing this box i'd throw a 2x4 on the top baffle to brace that and front/side walls and throw some dowel rods in between baffle and port/bottom and port

as long as you brace accordingly you need not worry

[MrBalll]

Yeah, pretty much just worried about flexing mainly being I will need to mount my amp on the backside of the box. The side that will face the front of the vehicle so I knew that's it's already frowned upon but if you are going to do it make sure the box is braced well enough to where it won't have too much impact on the amp.

I appreciate all the help with this, uhoh. Looks like I have all that I need to make my box now.

[Alex K]

Umm, im suprised nobody has caught this yet. But you have enough air space for ONE 18. Unless you think 4.5 cubes port INCLUDED is enough airspace, than cue me out. But You need almost twice the airspace you have so far.

edit, just say uhoh's post.

Edited February 25, 2011 by Alex K