I am a 50/50 jazz/classical listener, and understand what you mean. However, if i was in your case, I would not compromise and would have preferred to wait for more money to get myself a better amp or speaker, or both, and no subwoofer at all. This way you spend more for sure, but you get much more benefit for music reproduction, for all music, everyday.
If you absolutely need the sub and want to keep your actual setup, the best choice and by far for sound per pound, which i personnally know about and amongst all other common names such as SVS, REL, etc... is XTZ. Their Sub 1*12 model is excellent, all necessary tuning possibilites are available, including the ability to play with open or closed vent, depending on personal perferences and/or environment, the bass is extremely firm and controlled, which would be an absolute requisite for classical and especially given the Dalquist nature which lacks bass, but which is fast, even more so with classD amp. The XTZ frequency range is wide, down to 19 and up to 160Hz. The price/quality ratio is near unbeatable, and they sell direct. You dont need a lot of power for sure, with classical you need full control and sound coherence.
If you absolutely need the sub and want to keep your actual setup, the best choice and by far for sound per pound, which i personnally know about and amongst all other common names such as SVS, REL, etc... is XTZ. Their Sub 1*12 model is excellent, all necessary tuning possibilites are available, including the ability to play with open or closed vent, depending on personal perferences and/or environment, the bass is extremely firm and controlled, which would be an absolute requisite for classical and especially given the Dalquist nature which lacks bass, but which is fast, even more so with classD amp. The XTZ frequency range is wide, down to 19 and up to 160Hz. The price/quality ratio is near unbeatable, and they sell direct. You dont need a lot of power for sure, with classical you need full control and sound coherence.