ZVX 18 box problem

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Hi everyone

I need some help over here with the box I made for my zvx 18.

I don't know if it's caused by too much volume or too much port.

The problem is that It produces less spl than my vvx 15 made and I think that the port's output is kinda slow or delayed like the air is moving slower compared to the air that my vvx made.

the specs:

net volume (considering sub): 4.52 cuft.

port area: 72.54 sqin

16.05 sqin per cuft

tune 29 hz

I'm using a crescendo audio symphony 1500.1 @1 ohm.

port firing back sub up (I have a big skyhole)

what should I do? shrink the box volume? or shrink the port??? or maybe I tuned way too low??

Please help to figure out this.

Thanks!

Car is a 2008 Hyundai Azera

[ToNasty]

Tuned to low for 1 thing. Also the box is to small. Should be 6 cubes. Tuned to 32-34

[Joe X]

No subs up on a trunk car, also tuning is way low, also it seems you've got steep group delay.

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so any way to fix this box? and I can't make sub back because the box won't enter to the trunk.

[Joe X]

There's this type of box to fit 18s in trunk cars - reverse mounted, sometimes will work if the mounting depth of the sub do not exceed the height of the trunk in the installed position - many times not the case:

For trunk cars 2 12s or a few times 15s if space will allow is the best solution.

[Cj Kumz]

The site recommends 4 cubes for your sub at 1500 rms. With a 4.5 box you are reducing the mechanical power handling of the sub. So I would suggest adding wood blocks inside to reduce to 4 cubes then hear how it sounds. But as JoeX has said sub back works better than sub up in a trunk car.. And a 15" in a correct box and setup will beat an 18" in a wrong setup. What direction did you have the 15" facing in the trunk??

[[email protected]]

There's this type of box to fit 18s in trunk cars - reverse mounted, sometimes will work if the mounting depth of the sub do not exceed the height of the trunk in the installed position - many times not the case:

For trunk cars 2 12s or a few times 15s if space will allow is the best solution.

I reduced the port lenght now it should be tuned around 32hz, box volume now is 5.35 cuft and 13.55 sqin per cuft.... I have to mount the sub and listen the new tune.

The site recommends 4 cubes for your sub at 1500 rms. With a 4.5 box you are reducing the mechanical power handling of the sub. So I would suggest adding wood blocks inside to reduce to 4 cubes then hear how it sounds. But as JoeX has said sub back works better than sub up in a trunk car.. And a 15" in a correct box and setup will beat an 18" in a wrong setup. What direction did you have the 15" facing in the trunk??

about the old setup, it was a sub back port back with a 1:1 ratio port, the problem was that with the nendo amp the coil started to heat too fast and the glue smell started to come out the box, that's why I bought the zvx... I wanted a 15 but the only ones that were at half the price were the 18s...

Now I did a box as joeX suggested and this is the outcome (I will use the same box, just have to add another top and the angled side)

this box is 4.05 cuft net, 17.9 sqin per cuft and tuned to 36 hz.

You guys think that I should make the angled modification or should I stay with sub up?

Thanks!

[ToNasty]

You need atleast 5-6 cubes. 16" of port per cube

[Cj Kumz]

The angled box will work way better than having the sub up. Don't forget bass also comes from the cone of the sub. So you need space for the waves to move properly. And 4 cubes will be fine cause that's the manufacturers spec.

[Joe X]

OP as before even if you mod the box you may find that the motor will hit the rear deck in the slanted mounting position, make sure you can actually fit the sub before going into any modifications.