Bing's earliest appearance as a vocalist on network radio most likely occurred January 4, 1928, in a special NBC broadcast called "The Victory Hour" featuring the Whiteman Orchestra. In February of the following year Whiteman began a weekly radio show sponsored by Old Gold cigarettes that often featured Bing as a soloist or with the Rhythm Boys. The series continued through May of 1930. No recordings are known to exist of Bing from any of these early broadcasts. According to radio historian Elizabeth McLeod:
These programs, as far as is known, were never recorded -- a great tragedy, since the Whiteman band, then at its peak, not only featured Crosby but also the legendary Bix Beiderbecke. Whiteman's collection of broadcast recordings is archived at Williams College is Massachusetts, but the earliest discs in the collection date to 1932. It's possible that some earlier discs are missing from this collection, however -- I've seen 1931-vintage ads for a Chicago aircheck studio which mention that Whiteman was one of their clients, but have never run across the recordings themselves. It is believed that a number of discs were pilfered from the Whiteman collection before it could be transferred to tape, so there might be important material floating around out there someplace...
Upon the demise of Whiteman's Old Gold radio show, Bing and his fellow Rhythm Boys began singing with the Gus Arnheim band at the Cocoanut Grove in Los Angeles. The Grove had its own broadcast equipment, and the performances were often broadcast throughout California. Bing sang at the Grove with Arnheim for 10 months -- until May 1931 -- but no recordings of these broadcasts from the Cocoanut Grove were known to exist until a set of discs were discovered in the 1980s. According to McLeod:
No positive explanation of the origin of this recording has surfaced, but
there are theories. Perhaps the most reasonable explanation to be offered is
that MacGregor was considering the production of a series of syndicated
programs featuring Arnheim's orchestra, and intended to use the recording
in question as a sample. As it happened, MacGregor was beaten to the
punch by his prime competitor, Transco, which signed several of the
Cocoanut Grove bands for syndicated programs. By the time these
recordings finally appeared on the market, Crosby had left Arnheim, and
had been replaced by Donald Novis.An interesting recording was found in the archives of the
C. P. MacGregor company back in the eighties, and seems to date to May
1931. Crosby and Loyce Whiteman are the featured vocalists. While it is
possible this is an actual broadcast recording (that is, a recording made
off the air or off broadcast lines), there is no way to authenticate it.
It is quite possible that it is not a broadcast recording at all, but
rather a live recording made at the Grove during a set by Arnheim and
company. That being so, the earliest *fully-authenticated* broadcast
recording of Crosby would be that made by Victor of his first CBS
sustaining broadcast in September 1931.