Fi Q15

[HitManSE 10+ year member]

LOL. I just started doing my max today, starting with the trunk. Finished it up mostly (exculind the rear deck and lid). My back hurts like a bit*h.
The box is gonna be a PITA to get in but i guess I'll have to tilt it to the depth side and then slide it in somehow. So 4cuft with what tuning? 32 or 28 or something else?

Using 1" MDF, the interior air space not including sub and port displacment (or possible bracing) is apprx 3.7ft for the specs I listed. Add the sub and port, and im sure you'll have well under 3ft.

Thats what I meant when I said getting a 4 cube box into your trunk is going to be a task. The largest recommended on FI's site is 4cu ft and the lowest listed tuning freq is 28hz.

What you choose is completly upto you.

Remember the lower the tuning freq, the more space its going to take up in the box. How you go about it is your choice, since your in NJ you could always PM Don aka 6spdcoupe and see what ideas you guys can come up with. The man knows his audio quite well & im sure he'll be able to help you out.

 

[JiggaD369 10+ year member]

Someone recommended 32hz and I'm leaning towards 28. One thing I didn't state is in the future I might be upgrading to a Mag. On SI's site, they list the sub enclosure for a 15 Mag at 3.5cuft @ 30hz. I'm thinking of making a 3.5cuft @ 30 right now so it can work in the future also. With a smaller box, I should be able to push it at 1200w at 1 ohm load for the Q. Good or bad idea?

BTW, where can I find 1" mdf?

 

[HitManSE 10+ year member]

If your going to get the Mag not too far down the line, then just build the box @ 3.5 and tune it to 30hz. I dont think the Q is going to complain.

The power you'd be feeding the Q, even it being 1200 rms should be fine. Just set the gains right and you'll be set.

As for the 1" MDF, id prob start at the local hardware store (obvious answer, lol) HomeDepot, Lowes, im not sure what else you have in your local area.

 

[JiggaD369 10+ year member]

I work at Lowes and they only carry 3/4". I was thinking of making a 1.5" thick enclosure but too much work. Would it be possible to make that box with two ports. one on each side?

 

[HitManSE 10+ year member]

I work at Lowes and they only carry 3/4". I was thinking of making a 1.5" thick enclosure but too much work. Would it be possible to make that box with two ports. one on each side?

You could always just use 3/4" all around, add some bracing and use 2 layers of 3/4" on the face of the box were the sub would be mounted.

Ofcourse you could use 2 ports ( download WinISD ) but its going to take up more room.

 

[JiggaD369 10+ year member]

When I use WinISD, what does VENT MACH mean? It changes colors (red and green). Do i adjust it keep it green? Is there a number I should adjust it to?

 

[HitManSE 10+ year member]

I guess you have a diff version of it then I do. Unless you clicked on a diff setting. Mine does not say the word MACH anywere I look.

Mach however, from my understanding usually refers to speed.

IF it indeed is refering to the velocity in the port, usually the lower the speed, the less chance of huffing/port noise. Personally I dont worry about this too much, so long as you have atleast 15" (give or take) of port area per cube ft of air space you should be just fine.

Ive ran as little as 6" port area per cube ft of air space without any port noise...none that I could hear anyway lol, I sure wouldnt run that low a # again though.

 

[JiggaD369 10+ year member]

When WinISD says I need a specific VENT LENGTH, is that length from front of the vent to middle of the box (90 degree section? IN the pic, is it the RED line area or is the vent length from front to the back of the box?

 

[HitManSE 10+ year member]

When a specific length is listed, it means from the front all the way to the end. However long that might be.

The rest of the question isnt specific enough to give a solid answer. I hope your not refering to the pic of the box as a guideline of how the box should look.

Check out This thread to see how the ports length is measured.

I still think you're going to need to run an outside port design to be able to fit a box that large. The limited size has been the source of many headaches induced by trying to design a box that could fit into the **** thing.

 

[iamamp3pimp 5,000+ posts]

Vent length explained by pics

Lets say that you need a perfect 30 inch long port, the port begins at the opening of the box, and not at the beginning of the first port piece (.75 or 1.5 inches in) this particular port is 4 inches wide, meaning that through the whole port, it needs to be 4 inches in diameter, or as close as possible @ all times.

since it is 40 inches wide, we all agree that the center part is 2 inches away from each wall, meaning that the length of the port extends past the first wall, and on to the second, but what you have to remember is that is also port length that needs to be accounted for.

ths pic explains it better than i can though

 

[JiggaD369 10+ year member]

I don't see a pic Pimp.

Can you guys point me to a box plan which has dual ports and it's around 3.7 tuned to 27-28hz? I looked in the Box Plans page here but only found 3.8 @ 29.

 

[HitManSE 10+ year member]

Ill put it as plainly as I can.

There is no box plan that has 50" or so port area, and is going to be 3.5+ cu ft after both sub & port displacement that can fit through the opening in your trunk.

The only possible way is to somehow build a box inside your trunk to make use of any additional space you can use.

The #'s I gave earlier are pretty much the limit to the box size that will fit through the trunk opening, I had to literally force that thing in through the opening.

I have written out many box plans, trying to build one the size your talking about & there is just no way that I can think of that will allow that box to get into your trunk.

If you come up with something, more power to you, please tell me about it lol

Using the outside dimensions I listed, after say 40” or so of port area & sup displacement,

the air space inside the box will prob be knocked down to about 2.5cu ft of air space (give or take) I don’t know what else to say about it.

I wish I had an SUV sometimes, lol

 

[JiggaD369 10+ year member]

Lol. SUV's are the ultimate when it comes to this type of issues. Anyways, the Max has way bigger trunk than my previous car (94 Accord). I had to force a 2.5cuft box in there and man did it take some work lol. I gues ill just have to go sealed or make a box and just leave it in (give or take how it looks). I just don't like the look of a simple box sitting in the trunk. Guess my bad luck.

P.S. Check this site out. PRetty cool. I might opt for the compact alignment.

http://www.subwoofertools.com/forum/ported-box.asp?Ew=33&Eh=16.5&Dia=9&Xmax=27&Vd=.19&NumW=1&Vb=&Fb=28.83&Qts=.49&Vas=4.767&Fs=24.9&CE=1.5