hey i went to a website that this site recomended to see what the diameter of my port would need to be to not get port for a vmax 15 and it gave me a figure of about 9 inches. that is huge!!! i thought u only needed a 6 inch port for a 15. please explain this to me. this has confused me.
ok blare i ran a box size of 3 cf. for a 15. which can happen for a woofer of that size at 35 hz and it came out to a port volocity of .05 at 500 rms power; and that is a number you would want to shoot for volocity wise for an spl box. Now take that same woofer and tune it lower or add more power to it and you have even more port volocity. So now you can see why they recommend one 9 inch port. (by the way the port came out to 40 inches long) A slot port would be called for.
Actually dick, if you have a ported box built and tuned correctly, you can still achieve good sq. And you can still get great spl with sealed boxes. I know you may reach higher decible's with ported boxes, but IMO sealed sounds a lot nicer. It's cleaner and tighter.