Can we combine the advantages of line- and point-source technology into one speaker?

[Arthur Jackson]

Can we combine the advantages of line- and point-source technology into one speaker?

I'm now inspired by vintage ADS L2030 speakers. They're described as being designed to combine the benefits of both line- and point-source technology in a single speaker. They use four midrange drivers and have a midrange toggle switch for switching between line-source and point-source operation.

According to the brochure, the main bigger midrange is more efficient than the remaining three smaller midranges. In point-source mode, only the main bigger midrange sings, whereas, in line-source mode, the four midranges sing concurrently. The line-source mode is advertised as "weighted line-source", which is also promoted as combining the advantages of both line-source and point-source technologies.

However, these speakers were produced in the early 1980s. I have never heard the sound of these speakers, though.

I'm curious whether this idea should be revived in modern design. I'd like to hear other people's thoughts.

My understanding was the line source mode was a standard three way loudspeaker with the two woofers crossed over to four midranges and then to the tweeter.

In point source mode the array of midranges were progressively crossed over up to the tweeter. This allowed for four midranges to cover the lower midrange and one to cover the whole midrange. The other two midranges progressively added in more upper midrange. They used varying low pass filters, all midranges operated at low frequencies then three, then two, and finally one at full midrange bandwidth crossed over to the tweeter.

 

[Arthur Jackson]

I think it also had an electronic crossover so you could bi-amp.