So, your plan is to turn the sealed enclosure into a ported one? I just want to make sure I understand this correctly. There is so much that has to be understood for your situation, that a lot more information would be needed to give you an idea of what to do accurately. I will keep it simple for now, so, what driver are you using? I know you said tc axis, but size and specs are very important to know as mentioned before. Also, specs on the box such as internal dimensions, NOT CUBIC VOLUME, I dont care about cubic volume, and the port size and length you plan to use to put in there, which we know you want either 1 or 2 6" round ports, but no specified length or anything is mentioned either. Here is the very basic info needed for anyone to do anything with this properly:
1. Sub a. size, sd, fs, qts, vas
2. box a, height, width, depth-all internal
3. port a diameter, and length.
4. response cutoff or tuning
5. power you are going to use.
Then anyone can figure a very basic idea of how many you need.