To make a comparison between various microphones, this term was introduced to indicate the power output of a nondirectional mike in relation to a directional mike of equal sensitivity in a diffuse sound field. An ideal cardioid mike has a DC of 3. Since the intensity of sound decreases as the square of the distance, the cardioid mike may be used at a distance of 1.7 times farther than a nondirectional mike with the same amount of disturbing ambient noise.
"I have been looking for someone to transfer two very old and precious recordings for years. We had no way to listen to them given the outdated technology. One was a USO recording my dad made in WWII. He was 18 and sending a letter home to family. My dad died when I was 9,so hearing his voice again was something I longed for. My sister was ..."
