I have heard both and thought the bass on the Source was very uneven and stood out. The sweet spot is also very small on the Sourse. The magnepan 1.7 were just as detialed with out the bass lumps.
The Logans will be a little faster and more transparent in the midrange but the trade off would not be worth it for me. The bass goes to the 1.7 hands down. The highs are very different from each other. Logans are detialed and rolled off a little. While the 1.7 are a little forward and agressive (adjustible with resistors from what I under stand).
PS. Sorry about the spelling I posted from my phone...
The Logans will be a little faster and more transparent in the midrange but the trade off would not be worth it for me. The bass goes to the 1.7 hands down. The highs are very different from each other. Logans are detialed and rolled off a little. While the 1.7 are a little forward and agressive (adjustible with resistors from what I under stand).
PS. Sorry about the spelling I posted from my phone...