Tuning 120^2 of port to 38 hz?

[bunkerking09 10+ year member]

thats what i got so far...

 

[bunkerking09 10+ year member]

now how in the hell do you cut out circles in sketch up?

 

[Farva 10+ year member]

Just use WinISD Pro for ease of port calculation. In your situation, say its a true 9.5 cubic foot of net airspace, your port would need to be 14.375 inches long to achieve 38 hertz tuning.

To cut out the circles use the push/pull.

 

[bunkerking09 10+ year member]

i've tried messing with that program...i had little luck

 

[netzero 10+ year member]

now how in the hell do you cut out circles in sketch up?

I'm no pro at sketchup, but what i do is find the center where i want the sub with the tape measure tool then use the circle tool and make the circle on the face of the box. Then use the push/pull toll and push into the box .75" or 1.5" depending on if its single/double baffle. Then just click and delete the face inside the circle so it opens it. Hope that helps.

 

[01 S 10 10+ year member]

on the carstereo calc... if your selecting "slot" port you need the width of the box to be the largest number (your 20" instead of 6"). a port that size + bracing + sub displacement will be more than .5 cubes from your 10 cube gross. You need to figure out how much net airspace you want and find the size of your port, then calculate how much airspace the port, bracing, and sub displacement take up, add all those together and add it to your net volume to figure out the gross volume. now you will have to make adjustments to the dimensions of the box to give you exactly that right amount of airspace.

 

[Mexar 10+ year member]

What 01 S 10 said... the reason for the difference in numbers, is that on the carstereo port calculator, is when you select slot port, it just tells you the wall length to cut, what it DOESNT tell you, is that half the height of your port, continues to act as a port along the slot wall, so when you put in 20X6, and it gives you 11.53 , that's because it's actually supposed to be 14.53 long. When you turn the port the other way, at 6X20, it's adding the 10 inches from the 20 high, and leaving you with only 4.53" of actual port walls... If you notice when you add the 10 to the 4.53... both ports end up the "same length" ... both numbers work, and it's a good way to get away with a shorter port if your box isn't wide/long enough for it, but you can support the height

 

[bunkerking09 10+ year member]

on the carstereo calc... if your selecting "slot" port you need the width of the box to be the largest number (your 20" instead of 6"). a port that size + bracing + sub displacement will be more than .5 cubes from your 10 cube gross. You need to figure out how much net airspace you want and find the size of your port, then calculate how much airspace the port, bracing, and sub displacement take up, add all those together and add it to your net volume to figure out the gross volume. now you will have to make adjustments to the dimensions of the box to give you exactly that right amount of airspace.

so the amount of airspace the port takes up is not part of the net volume of the box? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

man i ****.