Ok i was just punchin up stuff on a port tuning calculator. Desired tuning:25 hz Number of ports: 2 round ones Diameter of each port: 1 inch Box volume:2 cuft Ok this seems odd but it said 2.66 inch length would make it 25 hz? is that true
Wich brings me 2 my next question(its more like a theory) can a smaller diameter account for sum port length? i came up with a hypothesis for this theory, that the smaller the diamter would make it 2 where u can have smaller length. I tested my theory with 2 glass bottles: 1 short small diamerter hole and 1 tall big diameter and the smaller one achived a lower frequincy lol
Yep. 1 inch is WAY too small for a ported box. 2 1 inchers aren't any better. For subs, I recommend at least a single 4" round port for any subwoofer, especially 10" and above.
It just occurred to me after talking with someone from another board yesterday and thought about it this morning that if you take a slot port and let it be wide at one end and narrower as it went up you would have a higher port tune than if you let it be open even amounts the whole way through the slot port...intresting thought
"Yep. 1 inch is WAY too small for a ported box. 2 1 inchers aren't any better"
Actually yes they are better the more one inchers you have...one 1 inch round port times 3.1416=3.1416 port area two one inch round ports times 3.1416=6.2832 port area add more you get enough port area for a 10 inch subwoofer and less port length than a 4 inch port
A port is not just a hole in a box, if it was yes, you would only have that much port area,but you have legnth and circumference, so technically its a cylinder. You have to put the volume of a cylinder, which is the area of a circle times the legnth of the port. 3.14x(.5x.5)=.785x4=3.14x3.369= about 11sq.in. Someone correct me if I made a mistake.
Oh dear not again. "Port area" is just that the area of the port. A cylinder has a VOLUME. This is only helpful in port terms when calculating space taken up by a port in an enclosure. The port area and tuning frequency will determin port length. Feel corrected. BTW Volume is measured in cubic inches.
I want to see what sean has to say, but I think I know what you're sayin. If you could put enough 1 inch squares in a round port to fill it up, that would be the area of port right? So in a 1 inch round port, you could put 1 square in it. If you have 4 ports thats about 4sqin. Is that what your saying? This is the reason I like slot ports. lol
REDSKIN has got you guys on this one. You don't just calculate the port Volume. You find the port area, and then calculate the length based on the box volume and desired tune.
How much easier does it have to be? plus it's much easier making round ports. All the design programs calculate round ports so whats the problem?
"yeah,ok just makin sure. thx I was talkin about round ports though.".....Errr so was I but you seemed to be having trouble caculating areas of round ports so I switched to square ones so you could grasp the idea that 4 1" ports don't equal 1 4" port.
I'm still learning about ports, so I might struggle sometimes. My geometry teacher wasn't all too good either. lol One more thing. Do you know what port resonant freq is.