LS, you seem to have a case of the planar bass blues. This is caused by your having discriminating tastes, being able to appreciate what planars can do for you from mid-bass to treble. The fact that you find your sub to be too slow is just further evidence of that.
Sorry, but I have never heard a sub which was fast enough for Magnepans. I have rarely even heard a cone speaker which can differentiate notes in the bottom octave, for that matter - mostly they just thump and thud in a sluggish monotone - unless you spend real money.
The only solution which satisfies me, is to buy a planar speaker with as much low frequency extension as the budget allows. Even ancient MGIII's extend the bass down to nearly 30 Hz, which is really plenty low. To test this, put a 12 dB filter with a 30 Hz crossover in front of your sub, and dial the sub down to 30 Hz as well. Then play a record with lots of bass. I think you will be surprised at how little signal comes through. Unless you goose the bass with tons of gain, of course.
I think you have no choice but to save up for pricier planars. Put it down to the cost of having good ears. Good luck!
Sorry, but I have never heard a sub which was fast enough for Magnepans. I have rarely even heard a cone speaker which can differentiate notes in the bottom octave, for that matter - mostly they just thump and thud in a sluggish monotone - unless you spend real money.
The only solution which satisfies me, is to buy a planar speaker with as much low frequency extension as the budget allows. Even ancient MGIII's extend the bass down to nearly 30 Hz, which is really plenty low. To test this, put a 12 dB filter with a 30 Hz crossover in front of your sub, and dial the sub down to 30 Hz as well. Then play a record with lots of bass. I think you will be surprised at how little signal comes through. Unless you goose the bass with tons of gain, of course.
I think you have no choice but to save up for pricier planars. Put it down to the cost of having good ears. Good luck!