Thinking about my history, I heard this on a low frequency.
There was another sound too, of such low frequency as almost to be felt rather than heard.
The light from a star moving away is seen at a lower frequency, or more red.
E1b1a is also found at low frequencies in this area.
Light of low frequency could carry more energy only for the same reason.
Younger people have the ability to hear lower and higher frequencies.
Lower frequencies in the bass range are difficult to form.
Lower frequencies than can be heard are detected this way.
The Sun's sound waves are at such a low frequency our ears can't hear them.
Other studies have found the theme, but with lower frequency and popularity.