Stacking Speakers

[GM]

an additional 2 cents worth, sometimes simply unhooking one of the HF sections can be a significant improvement in a "stacked" arrangement.

Yeah, historically I couldn't tolerate such a set-up of mismatched parts, so at best it would have been with the Santana's tweeters disconnected and cabs right side up to get the woofers closer and then reduced the M19's horn shelving as required to tonally balance it out as much as practical.

GM