Quote Originally Posted by RGA
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As for bass - Art measured 25hz flat in room response. As engineer Donald North noted - corner loading adds 18db to low bass notes. Looking at the Stereophile graphs - look where db level is at at 18hz and then add 18db. Audio Note only needs about 13-14db of those 18db to meet their spec of 18hz-6db. In fact they're usuable to 12hz. ...
Accepting the 18 dB corner boost for "low" notes, then the numbers are more or less plausible.

The closest standard Seas 8" woofer is the Presitige CA22RNX, (here). According to my Bass Box Pro program, in a 2.7 cu.ft box, (about the size of AN's), the -18 dB point is about 16 Hz. (This make sense since the -3 db point is around 31 and the roll-off for a standard vented box is 18 dB/octave.) So AN's spec is arguably conservative stating -6 dB at 18 Hz.

On the other hand with the steep 18 dB/oct roll-off it's pretty difficult to imagine a smooth compensation with corner placement -- what is the roll-off of Donald North's 18 dB boost with rising frequency??? For me it's easier to imagine setting up for smooth response with the closed box AN-K model with a 6 dB/oct roll-off. BassBox estimates a -22 dB at 17 Hz for the same woofer in the AN-K's approx. 1 cu.ft box-- yet for that model AN makes the much less extravagant claim of "50 Hz to 20 Hz (-6 dB)".