A slight off topic question. I see that the RBH sub has some high THD ratings at 25hz and below. My question is, what does high THD sound like? Without measurement tools, can the human ear easily detect the distortion. This is debate-able. Reason being is that the distortion is very high and on top of that the actual output level of the fundamental is very low. But the output is pretty much all distortion and very little useful output anyway, so the distortion may not matter much. The output is essentially not of useful level to begin with so it really doesn't matter what the distortion amount is. All resonant systems behave like this below their pass band not just the RBH. In other words a vented system operated below tuning. Lower distortion is of course better but if comparing to another subwoofer and neither have useful output where comparing the distortion to begin with it is moot. For the RBH SX-12 I surely wouldn't worry much about anything much below 25Hz. It's just not designed to be effective there.
