lol... i know some people try to confuse you....... anways a SQ sub is that which integrates with you setup and is more musical, hit bass notes precisely and accurately. Low note are inaudible i-e 30ish hz dont care about em if u are after SQ
The bass form 3001 over comes the mid bass, mid range and highs. a bass heavy setup is never a SQ setup.
For SQ vs SPL sub (usually) look at the surround of the sub. if it is over hung and large, that sub is more towards SPL. If it is small the sub is more towards SQ.
Reason:
The over hung surrounds can never control the sub motion accurately and quickly, like in the case of 3001, thats why it does not sound accurate in highs and thats the bass spectrum one should be worried about since thats the part where midbass gives in and sub takes over.