Principles hold true today, in large part. Like how they placed the mic on the table using tape for a 'shock mount'. And the large panels using acoustical sound tiles. Bulky; I wonder how well they work?
https://www.youtube.com/watch?v=Zd0-YZSHYQ4
https://www.youtube.com/watch?v=Zd0-YZSHYQ4