Does anyone know the ideal enclosure volume and port dimensions for the JBL 2012H Midrange/Mid-Bass Transducer?

JBL's product sheet recommends 10-30 liters and an example of 8.5 liters tuned to 75 Hz.

What would the size of a 75 Hz port be?



I happen to be building a version of Daniel's Ancient Audiophile's quest for the Ultimate Home System.



So, any advice would be welcome.