JLs not only have beastly build quality, they have a suite of controls and features to blend the sub with your speakers *and* the room--adjustment controls for continuously variable phase control over a wide range, volume, crossover, a polarity switch, and ARO (automatic room optimization) complete with calibrated microphone.
I've heard a pair of Magnepan 20.1's augmented with a pair of Fathom F212's and the integration was completely seamless. Although the JLs are capable of great power and thunder, they are also the best I've heard on seamlessly integrating for a music system and never calling attention to themselves.
I have an audiobuddy who uses the $679 sealed SVS to augment his Magnepan 1.7s and he likes it a lot. The SVS's seem to be a pretty good value. Their 13" driver reminds me of the JL approach, and their $2K 3-port model (using that 13" driver) has four rolloff profiles, depending on how many ports you plug. All 3 ports plugged creates a gentle rolloff that extends usable FR to around 14 Hz. That would be a good config for music. The gentle rolloff also avoids the big port resonance boom, so again, it's better for blending for music than with all ports firing.
I've heard a pair of Magnepan 20.1's augmented with a pair of Fathom F212's and the integration was completely seamless. Although the JLs are capable of great power and thunder, they are also the best I've heard on seamlessly integrating for a music system and never calling attention to themselves.
I have an audiobuddy who uses the $679 sealed SVS to augment his Magnepan 1.7s and he likes it a lot. The SVS's seem to be a pretty good value. Their 13" driver reminds me of the JL approach, and their $2K 3-port model (using that 13" driver) has four rolloff profiles, depending on how many ports you plug. All 3 ports plugged creates a gentle rolloff that extends usable FR to around 14 Hz. That would be a good config for music. The gentle rolloff also avoids the big port resonance boom, so again, it's better for blending for music than with all ports firing.