That sounds to be a remarkable speaker. I wouldn't have expected a football commentary to have enough low-frequency content to justify a horn of that length!
On reflection, I wonder whether it was one of these Westrex speakers borrowed from the local cinema.
https://www.radiomuseum.org/r/wester..._horn_16a.html . The Radiomuseum reference suggests that the folded horn design is equivalent to a 12-foot air path. Maybe the '17-foot long' claim wss the result of a little press hyperbole. The weight also fits with the Todmorden report
I find it impressive how the commercial incentive of 'talkie' films in the 1920s led to such rapid developments in speakers, largely in Bell Labs (Westrex). By 1930 we had speakers that would bear comparison with today's developments, perhaps give or take an octave or so at the top end. But I don't think their electro-acoustic efficiency has ever been bettered.
Martin