Can someone explain how to find the square inch per cubic feet when designing port?

[osiris10012]

Well looks like I have some more recalculating. lol. But at least I am getting close to having this bad boy designed. I can't wait, my e10 is suppose to get here sometime tomorrow. I really want to get this enclosure figured out.

[CleanSierra]

Programs such as http://www.carstereo.com/help/Articles.cfm?id=31 account for port displacement as you increase the length of port. The only thing you have to account for before hand is the sub displacement. No reason in trying to figure out net volume before calculating your port.

No.

Wow. Your convincing.

Though he didn't explain his No, if he said no, the answer is no. He's forgotten more about the subject than I'll likely ever know, he knows his shit.

[775Tundra]

Programs such as http://www.carstereo.com/help/Articles.cfm?id=31 account for port displacement as you increase the length of port. The only thing you have to account for before hand is the sub displacement. No reason in trying to figure out net volume before calculating your port.

No.

Wow. Your convincing.

Though he didn't explain his No, if he said no, the answer is no. He's forgotten more about the subject than I'll likely ever know, he knows his shit.

Not arguing at all. Not saying he doesn't know his "shit". I obviously folded. I see your one of those.

[Joe X]

Programs such as http://www.carstereo.com/help/Articles.cfm?id=31 account for port displacement as you increase the length of port. The only thing you have to account for before hand is the sub displacement. No reason in trying to figure out net volume before calculating your port.

No.

Wow. Your convincing.

There is a "formulas" link on that page, go there and you can see what the calculator does, there's nothing to suggest it accounts for displacements BUT I think the author of the webpage should state to enter "net volume" not "internal volume".

[775Tundra]

Programs such as http://www.carstereo.com/help/Articles.cfm?id=31 account for port displacement as you increase the length of port. The only thing you have to account for before hand is the sub displacement. No reason in trying to figure out net volume before calculating your port.

No.

Wow. Your convincing.

There is a "formulas" link on that page, go there and you can see what the calculator does, there's nothing to suggest it accounts for displacements BUT I think the author of the webpage should state to enter "net volume" not "internal volume".

Thanks joe-x. I started snooping around more when triticum agricolam provided his input. I think it was purely the wording that threw me off. I am glad that someone cleared that up.

[osiris10012]

Just curious but what calculator total should I use. I checked the car stereo.com calculator for my net volume and it said to make the port 26.25" long. I then checked the12volt.com and it told me 28" long? Which one is correct, lol? Is the 12volt compensating for something, because it is exactly 1.75" longer which is half my port width? My net volume after sub displacement is 1.28 cu. ft. and the port is still 3.5Wx5.25"H.

[Joe X]

Just curious but what calculator total should I use. I checked the car stereo.com calculator for my net volume and it said to make the port 26.25" long. I then checked the12volt.com and it told me 28" long? Which one is correct, lol? Is the 12volt compensating for something, because it is exactly 1.75" longer which is half my port width? My net volume after sub displacement is 1.28 cu. ft. and the port is still 3.5Wx5.25"H.

Those are small differences, bear in mind that port displacement needs to include all the port internal walls and the thickness of the wood parts over the transmission tunnel, and the sub displacement of course, I wouln't be sure on the 1.28 net.

[osiris10012]

Ok I redid it with the car stereo recommendation of 26.25 and after all displacement factored in I am sitting a net volume of .95 cu. ft. I will double check my calculations but I am pretty certain my gross is 1.38 cu. and the sub displacement is .1 cu according to sundowns site.

[osiris10012]

Alright I redid my calculations by taking the actual internal measurements with sketchup and found my gross volume was 2413.6875 cu. in. then converted it to cubic feet and got 1.3968 cu. ft. I am pretty happy with that because I only found out I have more volume than I originally thought. I am going to leave the port 16.25"L which will tune it in the high 34Hz range and leave me with a final net volume of .95 cu. ft including port and sub displacement. Do you all think this will be a good box? Here is a picture of my final design. Just need all of your final words.

[Joe X]

Your gross volume is correct, your net volume is nearly as you state but your stated tuning is off, it will be way higher than 34Hz.