Quote Originally Posted by Lansing4412 View Post
In A/B testing of the Altec 511 vs. the MR994A, even with PEQ correction, the 511 was not the equal of the MR994A. That's not to say that the 511 is a bad horn, just that the more modern MR994A is an improvement in design and performance.
No surprise there, the 511 was designed for a cinema screen's ~3 kHz ~flat BW limit whereas the MR was designed to EQ 'punch through' the screen to meet THX standards. Limit the two to the lower limit and it wouldn't surprise me if the 511 was best overall since the MR by design has a higher throat distortion.

From a purely SQ POV, Harry Olson's 1930s conical horns are a [major IMO] step up with Dr. Geddes's being the current SOTA horn/WG.

Stronger diaphragms = materials improvement

Improved phase plug designs = manufacturing improvement

Improved horn designs are just adaptations to the market's changing needs, but there's no new technology per se unless you consider DSL's Synergy concept, which I don't since its and the TH's roots are in Jensen's Transflex 'sub' [aka tapped TL, TTL nowadays].

Anyway, the pioneers proved that they understood the physics of sound reproduction to a fare-thee-well, literally 'writing the book' as they went along, making these 'improvements' all a function of computer aided materials, manufacturing advancements, so we'll have to agree to disagree and let the 'gentle reader' come to their own conclusions.

GM

PS: I like the way Tom Danley once responded to a similar thread, bemoaning that 'the ancients keep stealing all my inventions'.