You?re welcome!

The 604 is a near-field monitor and the M19 a far-field one plus designed to handle much more power, so pick the one that is the best ?fit?, though the ?rub? here is that neither one is optimum for most HIFI apps, though historically, the few that have converted the M19 concept to a low tuned MLTL were much happier overall, making the choice between the two a ?no-brainer?.

Factor in that to get a proper comparison the 604 needs to either be at ear height and the M19 adjusted for distance/slope to get the center of its horn?s ?sweet spot? at ear height or bring the 604 down and adjust it to have the same HF ?sweet spot?, doing it in a typical HIFI room would also require rolling off both speakers fairly high up due different cab tunings, room interaction [I?m guessing around 250-300 Hz].

Compared this way and fiddling with the M19?s tone controls to minimize horn size differences [?fullness?], I imagine that in a narrow ?sweet spot? there wouldn?t be a significant difference sonically, but run wide range and optimized for in-room response it?s going to be enough different to be an apples n? oranges choice to me.

Anyway, there are folks here with both, so they are the ones to best answer this one.

Really, based on your stated performance goals, thoughts, and not wanting to stray too much from the ?conventional wisdom?, it seems to me that a 604 MLTL with a 511 perched on top to make a three way is a good way to ?have your cake and eat it too?, and if you add the 416 as a helper mid-woofer, then system sensitivity can be 3 - 6 dB higher/channel.

Hmm, after 15 sec. of thought, this is my ?official? recommendation as it satisfies the XO point issues once the XO is dialed in phase wise [horn tilt + vertical driver offset] at the listening position to account for the large c-t-c spacing.

GM