Why do 45s have large holes?
A friend recently asked me why 45s have larger center holes than LPs. For her benefit, I’ll start with the short answer.
RCA versus Columbia
In 1948, Columbia introduced their 33 1/3 rpm LP format. Instead of adopting this format, Columbia’s competitor RCA Victor countered with the 45 rpm record in 1949. Columbia’s 10″ and 12″ records had the small center hole used on earlier 78s and still seen today on LPs. RCA Victor’s 7″ records had a 1 1/2″ center hole. Their turntables had a matching 1 1/2″ spindle, so even if you wanted to play a Columbia LP at the wrong speed, it simply wouldn’t fit.
Columbia’s LP format may have looked physically similar to the 78s it hoped to replace, but it had a few advantages. Look at the ad below as an example. Forty five minutes of music on a record versus two 45s for one short symphonic piece. And while the sound quality of 45s was, in theory, better than that of LPs, it didn’t seem to matter to the record-buying public. So LPs won out over 45s as the dominant format for records, while 45s were largely relegated to use as singles.