All newer receivers have it. Even the cheapest ones.
Adjusting the cross-over on the plate amp doesn't unburden the speakers BTW. You can set the sub's cross-over to 80 and just let the 60s play low. Or you could turn down the bass on the yammy and boost the volume on the sub.
Not sure you know but Andrew worked over the 125v4 good. It's almost as good as the 175v3. I'd bet it sounds better than the 175v3. Andrew's the real deal. He's an engineer's engineer. Do you know he broke the laws of physics on the Air N3? He's making 30 Volts from a 15 Volt battery. That's how he gets 75W a side. He takes constructive feedback too because he's humble enough to know goodness can come from many sources.
P.S. I should bring the M100s over.
