The Difference Between High, Middle and Low-Frequency Noise
You’re probably aware that different sounds have different frequencies, but what’s the difference between high and low-frequency sounds? And what about middle-frequency sounds? If you’ve been wondering about the differences between sounds of varying frequencies and how they affect you, read on.
What Is Low-Frequency and High-Frequency When It Comes to Sound?
When we talk about sound, we talk in terms of high and low-frequency waves. Sound waves are movements of air molecules that our ears translate into sound, and frequency refers to the number of cycles these waves complete in a second.
This measurement of cycles per second is expressed in Hertz (Hz), with a higher Hz representing higher frequency sound. Human ears can register sounds from about 20 Hz in frequency up to 20,000 Hz, depending of course, upon the hearer. People with hearing loss usually have trouble hearing sounds in the higher frequency range. Speech usually falls within the 100 and 8000 Hz range. People may start having difficulty discerning speech once it exceeds about 3000-4000 Hz. There are three types of sound waves, in general:
- Low Sound-Frequency Waves. Low-frequency sound waves often sound “lower’ to the human ear. When you turn up the bass on your stereo, you are creating more low frequency sound. These are “rumbly” sounds that you feel as much as hear.
- Medium Sound-Frequency Waves. Middle-frequency sounds are sounds that are between the 500 and 2000 Hz range, which is where you can intelligently determine human speech. Sounds in this range often have a tinny or horn-like quality.
- High Sound-Frequency Waves. High-frequency sounds can start at above 2000 Hz, although there’s a very wide range of audible sound in this region. At 2000 Hz, we say the sound gives “presence” to speech, speech sounds more real and authentic. By 10,000 Hz, you’re hearing sounds like crashing cymbals and chirping birds.
Low vs. High-Frequency Waves
It may help to think of low, middle and high-frequency sound with respect to musical notes. The lowest note on musical instruments like organs, tubas, pianos and cellos are all in the 5-70 Hz frequency range. Middle C in the treble clef of a piano is a medium sound frequency sound, just a little above 500 Hz. The highest note on a flute is at the low end of high-frequency range, about 2100 Hz, while the highest note on a standard piano is a little over 4000 Hz. In terms of your stereo, when you turn up the bass, you’re filtering out the high-frequency sound and getting more low-frequency sound, and when you turn up the treble you’re getting more of the high frequencies.
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