A woofer can 'tend' be be SQ, but if installed incorreclty, also can hamper output. If we really are speaking of SQ then, by all means, low volume it is...they still have proven then, as proven above. If true SQ is the goal in which you speak, then there you have it...proof done. Physics can say whatever, but if not installed properly, they sound like poop.A sub is made to reproduce low frequencies.
I would always tend to look more at power, placement, and components used for 80% of the judging, well over subs anyday. As thye are what reproduces the vocals, midbass, etc.
But it really is mis-leading to say they are not 'meant' for SQ, or cannot have SQ, as others can do it with great success. It's all false accusations...any sub can sound bad...if done incorrectly...no matter what physics says.
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