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Sine Wave A 440 Hz Concert Pitch for Ten Hours
Stop your brain from overthinking. You don't need an app. Ten hour Sine wave with no overtones which is called pure as it is only the fundamental frequency.
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Isadore "Friz" Freleng, credited as I. Freleng early in his career, was an American animator, cartoonist, director, producer, and composer known for his work at Warner Bros. Cartoons on the Looney Tunes and Merrie Melodies series of cartoons from the 1930s to the early 1960s.
Hawley B. Pratt was an American film director, animator, designer and illustrator. He is best known for his work for Warner Bros. Cartoons and as the right-hand man of director Friz Freleng as a layout artist and later as a director.