Nice job. Here's a link to an archive.org audio search for the year 1923. Be cautious with this because it's all self-tagged stuff, someone might have just been guessing; https://archive.org/details/audio?&and[]=year%3A%221923%22
Also be cautious if someone published in or from Europe instead of America - I discovered the woodcuts on the 1923 thing I was looking at were produced in Belgium originally by an artist that didn't die until the 1970s. According to the Berne Convention I wouldn't be able to use the woodcuts until the 2040s!