My guess is that the Crown amp is going to be really weak in regards to controlling the speaker (even though it’s rated at a higher power) -- Class D circuits can have a problem with weak bass when driving woofers. The Modwright amp is probably going to have a much better overall power supply and current delivery. One quick experiment you can try is to switch around the amps so that the Modwright is powering the woofer and the Crown is powering the mids/highs. If you get strong bass with the Modwright, you’ll know that the Crown is severely lacking. I’m going to guess that the Crown is going to sound weak when driving the mids/highs as well.
If the Modwright does sound better than the Crown when driving the woofer and you still want to bi-amp, you will want to look for a really strong high-current amp. Some thoughts would be to look for a pair of Emotiva XPA-1 monoblocks. For slightly less, you could try a pair of XPA-1L monoblocks (smaller) and then run them in Class A mode. They will still give a smooth/full midbass but they won’t have quite as much weight in the bass (though this difference is very very small).
If you want to spend more, I have heard that Parasound A21 has very strong bass. It may be sweeter/nicer sounding than the Emotiva’s.
Anything less is likely not going to be able to match the Modwright.
