help with box design for rockford p3 12

[Joe X]

Again, port optimizations become necessary when you expect higher peak airspeed in your port, will not be the case here, if you want to add corner smoothing, this is what to do:

This shows a slant in the port piece but it can also be rounded, just preserving port width at the turn by adjusting the size of the 45.

The ends outside and inside can be rounded or slanted as well.

[Joe X]

To forward some more infos:

Here's a link on how to how to calculate the end correction for slot ports:

http://www.jlaudio.com/header/Support/Tutorials/Enclosure+Ports/Tutorial%3A+Enclosure+Ports/287541

On a calculator Torres calculator is used on here but it's not really very accurate, the method you are using is better as long as you factor in the end correction in your calculations as indicated in the link.

[alaskanzx5]

I use Torres for getting the general design/idea then for tuning I double check it using winisd and 1-2port tuning calculators I can find from a quick google search. Usually use one on the 12volt car audio website and another on I think it is car stereo.com I'll find one and link it here.

[alaskanzx5]

http://www.carstereo.com/help/Articles.cfm?id=31

http://www.the12volt.com/caraudio/boxcalcs.asp

[Scalian]

Ok so if i read this and understood correctly for port correction in my aplication i would take half the witdh of the port and add it to the length?

[Scalian]

Playing around wtih WInISD and figured out I could over lay two designs on top of one another. Yellow line being the sealed 1 ft^3 box i have now and the white line benig the box designed in this thread. Looks like i should get a decent boost in bass from the new box. Cant wait till I get the day of friday to put it all together.

One question i have is about tuning. Kind of did some reading but never found the answer i was looking for. I figured if i tuned a box for 34 HZ that would be where the graph peaked at. But doesnt seem to be workign that way.

[Joe X]

Ok so if i read this and understood correctly for port correction in my aplication i would take half the witdh of the port and add it to the length?

Right but only if one of the walls of the port is also an external wall of the box, that said it is the case in your box.

On your other question, bear in mind a couple of things, WinISD does not account for environment acoustics so the curve is far from accurate due to the cabin transfer function, secondly it is a common misconception that the box will peak at tuning, that is usually not the case.

[Scalian]

So last night I was sitting around reading and thinking a little bit. I know thats where the problems always start.

I want to push my sub box up inder the rear deck agianst the rear seats. The way i have the box designed now there is alot of wasted area due to the slant of the seats. Can you do a slot port with the back wall of the box being angled? The other question is i started looking at the round ports and playing with them in WinISD. I assume that using a round port I could do the slanted back and the port vloume looked like it would be smaller and allow me to have a box that is smaller over all. Is this correct thinking ? If so I might try and throw a design together to save some more truck space.

[alaskanzx5]

If your seats fold down I would possibly slant the front of the box and have it fire forward into the cabin. Then seal it off from the trunk.

[Scalian]

Its in a 2009 altima so the seats do fold down, but i want the box easily removable as some time i need the pass through and more trunk space.

Someday ill buy a "TOY" car that i can commit to playing around with and do permanant mods.

Goal with this one is to get it sounding good on stock electrical with no real modifications to the interior.