I see it two ways Ryan:
The human ear is more keen on the 200-2k hz range than either above or below (just more keen, that's all....), and thus:
1. When talking about speakers, there are several aspects that graphs and measurements can't really tackle (although they do help point it out when it is an obvious flaw): Imaging, depth perception, acoustical signature (warm ->neutral ->bright), sound staging, etc.
With speakers, I usually tend to listen just with my ears, and if something is not up to snuff, I will check the measurements and graphs to see if something is showing up.
2. Subwoofers, I would say half and half for me. There is a strong correlation between what a sub measures and how it sounds....it's certainly not linear, but it is quite accurate. Flatter FR, the lower tuning, the group delay and decay responses, etc, they all relate fairly closely to how the sub "sounds".....
BUT, I would never buy a sub strictly on "measurements" or viceversa.
come to think of it, I don't think I will ever buy a sub...PERIOD!
DIY fo' life baby!!
