early 1970's speaker design Options

[Bartholomew MacG...]

Here's a quote from the engineer Siegried Linkwitz that was in an interview that was posted in Stereophile:

Dickson: You're most widely known as the developer of the Linkwitz-Riley crossover. Could you explain a few of the characteristics of this crossover?

Linkwitz: To answer your question, we need to go back to when I started out exploring the whole speaker issue in the early '70s. Then you could take the grille cloth off many of the available speakers and see a strange, almost haphazard arrangement of the drivers on the baffle. It really puzzled me and I wondered what was going on. So I asked some of the designers why they were doing this and they said; "Because we've found it sounds better."

As I looked further into this issue, I realized that two principal things were not well-understood. First, very little was known at that time about the effects of diffraction from the cabinet edges. Second, and more importantly, very little was understood about how phase-shift with respect to the current passing through the voice-coils of different drivers affected the polar radiation pattern of a speaker. In other words, the interaction between the electrical side of a driver and the acoustical response was not clear at the time. For example, the phase-shift between the current in the tweeter and midrange voice-coils, relative to the placement of these drivers on the baffle, affects the speaker's radiation pattern.

http://www.stereophile.com/content/siegfried-linkwitz-page-4



I was wondering if anyone knows if this is really true - that they just didn't know what they were doing and were in some way desinging the speakers by trial and error.