What audible improvements do you hear highpassing your Omega speakers? I would think adding crossover would take out some transparency. I think the Gallo CL-10 high pass at 100 hz, so that is pretty high.
I feared the same. Another link in the chain = loss of transparency and purity theory.
So initially I just used sub to supplement the bottom. After a bit I figured what the hell, may as well try all options...especially free ones. So I tried high-passing. And yes, the Gallo high-passes at 100hz fixed, not adjustable.
Overall sound took on an ease and purity and resolution over the entire range that shocked me. If a theoretical veiling is occurring I don't hear it. In fact, it sounds more transparent, resolved, open and refined. Sounds like a significant speaker upgrade. I assume removing LF from the mains, and concentrating their efforts at above 100Hz, allows them to play cleaner and louder with less distortion.
And of course, the LF got better as well, especially the mid-bass.... fuller and richer, better punch. I assume this is because the lower mid-bass and upper low bass , previously handled by the smaller mains driver (in addition to frequencies above that), is now done by the larger 10" sub driver. It just plays bigger with more authority and weight. Additionally, I believe the mains driver (now free of all below 100 Hz) now does a better job than previously with mid and upper bass reproduction, resulting again in better punch, weight and speed.
I have two friends that were also using Gallo subs to supplement their Omegas run full range. I asked them to high-pass their mains without revealing my results. When they did, they reported the same exact improvements I had heard.
I don't know what Gallo uses. Maybe some simple passive filter to not muck up the sound too much? If there is "mucking", to my ear the benefits outweigh it.