Why The Big Hole ? Compatible records

Did you ever wonder why 45 RPM 7 inch records have big holes in them? Well, let me tell you. 

Columbia and RCA  at the time were making their own versions of record players and they did not want them to be compatible with each other.

Columbia was the one that came out with the 12 inch 33 1/3 records that could play at least 15 minutes on each side. RCA came out with the 7 inch 45 RPM records that could play up to at least 3 minutes on each side.

When the patents ended they made record players that could play both formats as well for other speeds (16 2/3,  33 1/3,  45 and 78)

Also at the time they came out with stereo records which were not compatible on monoural record players the needle would not be able to play the inner grooves (left channel) .You would only be able to hear the right channel (outer grooves).

Then came  "Hit" records .Hit  recorded recent songs with sound alike artist and not the orginal artist. One "Hit"  45 record cost 35 cents compared to $1.00 or less for the orginal artist 45 RPM.

Hit did come out with LPs that were compatible with both mono and stereo record players ,but the records were 1 inch  thick. This made sure that both channels were being heard on mono record players (mixed channels) and still have separation with stereo record players.

This was at the time when the America state you're in took care of the copyrights, not like today were  you can create something and it is automatically copyrighted.
click here to hear Pretty Little Angel Eyes
The song above is recorded in Mono High Fidelity (20 cps to 20,000 cps frequencies. The range of sounds that can be heard by a normal young human ear)
click here to hear As Usual by Brenda Lee
The song above is recorded in High Fidelity Stereo.Genre non-twang country.