Editing Cover version (section)

===Rival outlets and popularized recordings===
This began to change in the late 1930s, when the growing record-buying public began including a younger age group. During the [[swing era]], when a [[Bobby-soxer|bobby soxer]] went looking for a recorded tune, say "[[In the Mood]]", typically she wanted the version popularized by her favorite artist(s), e.g. the [[Glenn Miller]] version (on RCA Victor's cheaper Bluebird label), not someone else's (sometimes presented on a more expensive record company's label). This trend was marked closely by the charting of record sales by the different artists, not just hit tunes, on the music industry's [[hit parade]]s. However, for sound commercial reasons, record companies still continued to record different versions of tunes that sold well. Most audiences until the mid-1950s still heard their favorite artists playing live music on stage or via the [[Old-time radio|radio]]. And since radio shows were for the most part aimed at local audiences, it was still rare for an artist in one area to reach a mass audience. Also radio stations tended to cater to broad audience markets, so an artist in one vein might not get broadcast on other stations geared to a set audience. So popular versions of [[jazz]], [[country and western]] or [[rhythm and blues]] tunes, and vice versa, were frequent. An example is "[[Mack the Knife]]" ("Die Moritat von Mackie Messer"), originally from Bertolt Brecht's 1928 ''[[The Threepenny Opera|Die Dreigroschenoper]]''. It was popularized by a 1956 hit parade instrumental tune, "Moritat", for the [[Dick Hyman]] Trio, also recorded by [[Richard Hayman]] & [[Jan August]],<ref>{{cite web|url=http://www.cashboxmagazine.com/archives/50s_files/19560303.html |title=Cash Box Top Singles 3/03/56 |access-date=2009-02-14 |url-status=dead |archive-url=https://web.archive.org/web/20081122043551/http://www.cashboxmagazine.com/archives/50s_files/19560303.html |archive-date=2008-11-22 }}</ref> but a hit also for [[Louis Armstrong]] 1956/1959, [[Bobby Darin]], 1959,<ref>{{cite web|url=http://www.everyhit.com/retros/index.php?page=rchart&y1=1959&m1=11&y2=1959&m2=11&sent=1&day1=1&day2=1 |title=Retro Charts |website=EveryHit.com |date=2000-03-16 |access-date=2016-11-21}}</ref> and [[Ella Fitzgerald]], 1960,<ref>{{cite web|url=http://www.everyhit.com/retros/index.php?page=rchart&y1=1960&m1=04&day1=3&y2=1960&m2=04&day2=3&sent=1 |title=Retro Charts |website=EveryHit.com |date=2000-03-16 |access-date=2016-11-21}}</ref> as vocal versions of "Mack the Knife".

Europe's [[Radio Luxembourg (English)|Radio Luxembourg]], like many commercial stations, also sold "air time"; so record companies and others bought air time to promote their own artists or products, thus increasing the number of recorded versions of any tune then available. Add to this the fact that many radio stations were limited in their permitted "[[needle time]]" (the amount of recorded music they were allowed to play), or were regulated on the amount of local talent they had to promote in live broadcasts, as with most national stations like the BBC in the UK.