Hi guys, I have all of the end caps cut for my 24 inch sonotube,a total of six of them.Im using the tempest driver, and a 6 inch pvc port.I am trying to use pat suns sonotube 2 as a close guide line.Fist of all I am going to put 2 3/4 inch endcaps into the top of the tube, and outside on the top will be a 3/4 inch by 25inch painted black.SO a total of one and a half inches of mdf inside the top of the 24inch sonotube.Bottum end cap will be exacly the same way, a inch and a half of mdf of endcaps inside the tube and one on the out side of the tube so the tube rests on it.. I guess I will tune it to 16.5 hz like pat did.I will put some batting matterial around the inside of the tube about what you did on your sonotube 2 project pat.I have the port cut out just like you did pat with a edge on the bottum endcap it will be resting on, good idea pat.I have a six feet piece of 24 inch sonotube and am ready to cut it. Can you do the figuring for me I dont now how to do it. I would like to keep the tube around 45 inches tall, because i will still have to put legs on it yet. Basicly when it is done with legs and all I would like it around 4 feet, give or take an inch, no big deal.How long does my port have to be to tune it to 16.5hz? thanks all.