Yes it frequency dependent. 20ms at 40hz 30ms at 30hz.even though ive spent countless hours over the last 6 months reading n learning about box designs n playing with enclosure apps it kinda donned on me today i really have no idea how the changes in the graphs when u add or subtract air space or makr the port longer/shorter. corelate to how its gonna sound. i dont even know if im right about what looks good on the graph
is there a level of group delay that i should try to stay under?