{"id":3495,"date":"2023-10-12T02:47:56","date_gmt":"2023-10-12T02:47:56","guid":{"rendered":"https:\/\/revolutionsincommunication.com\/viscomm\/?page_id=3495"},"modified":"2023-10-19T15:42:30","modified_gmt":"2023-10-19T15:42:30","slug":"recording-audio","status":"publish","type":"page","link":"https:\/\/revolutionsincommunication.com\/viscomm\/recording-audio\/","title":{"rendered":"Natural sound"},"content":{"rendered":"<p><em>By Nick Kovarik\u00a0<\/em><\/p>\n<p><span style=\"font-weight: 400;\"><strong>Acoustic or natural sound is <\/strong><\/span><span style=\"font-weight: 400;\">the propagation of vibrating energy through a medium; typically air. When an object vibrates, the air molecules near it compress and stretch, radiating outwards. This process is called <\/span><b>compression<\/b><span style=\"font-weight: 400;\"> and <\/span><b>rarefaction.\u00a0<\/b><\/p>\n<p><span style=\"font-weight: 400;\">There are 5 major properties of acoustic sound. For simple digital recordings, only the first two are fundamental. Recall them with the mnemonic, <\/span><b>F<\/b><span style=\"font-weight: 400;\">ind <\/span><b>A V<\/b><span style=\"font-weight: 400;\">ery <\/span><b>W<\/b><span style=\"font-weight: 400;\">ide <\/span><b>P<\/b><span style=\"font-weight: 400;\">arachute.<\/span><\/p>\n<ul>\n<li aria-level=\"1\"><b>Frequency:\u00a0 \u00a0<\/b><\/li>\n<\/ul>\n<p><iframe loading=\"lazy\" title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/qNf9nzvnd1k?si=bzbclHFrekQ6xR7t\" width=\"480\" height=\"315\" frameborder=\"0\" align=\"right\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<ol>\n<li style=\"list-style-type: none;\">\n<ol>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">The number of <\/span><i><span style=\"font-weight: 400;\">compression<\/span><\/i><span style=\"font-weight: 400;\"> and <\/span><i><span style=\"font-weight: 400;\">rarefaction<\/span><\/i><span style=\"font-weight: 400;\"> cycles that a vibration completes in one second, measured in hertz (Hz.)<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Most people are able to hear between 20 hz (ultra low frequencies) and up to 20 khz (20,000 hz, which are ultra high frequencies.)<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">So we could say that the maximum range of human hearing is composed of approximately 10 octaves. For reference, a grand piano with 88 keys<\/span>\n<ol>\n<li style=\"font-weight: 400;\" aria-level=\"3\"><span style=\"font-weight: 400;\">20-40 hz, 40-80 hz, 80-160 hz, 160-320 hz, 320-640 hz, 640-1.28 Khz, 1.28-2.56 Khz, 2.56-5.12Khz, 5.12-10.24 Khz, and 10.24 Khz up to the maximum range of hearing.<\/span><\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<ul>\n<li aria-level=\"1\"><b>Amplitude:<\/b>\n<ol>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">Amplitude is the power of sound waves, experienced as loudness. If we think of <strong>Frequency<\/strong> as an X-axis (representing time,) <strong>Amplitude<\/strong> would be the corresponding Y axis (representing intensity.)<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">Loudness in audio is measured in <\/span><b>decibels (dB) <\/b><span style=\"font-weight: 400;\">which has no specifically defined physical quantity. The <\/span><i><span style=\"font-weight: 400;\">decibel<\/span><\/i><span style=\"font-weight: 400;\"> is a logarithmic function that is used to compare the ratio of acoustic energy between two sources; typically between acoustic energy (Sound Pressure Level \/ SPL) and an electrical signal.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">The reason the <\/span><i><span style=\"font-weight: 400;\">decibel<\/span><\/i><span style=\"font-weight: 400;\"> is a logarithmic measurement is to make managing loudness simpler, because the human ear is capable of hearing acoustic energy at a ratio of\u00a0 1:10,000,000 and greater. If our hands could measure weight the way our ears measure loudness, we could accurately weigh both a feather and an elephant.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">In general, an increase of 6dB is a doubling of perceived loudness, and a change in 1dB is about 12% of the signal. Small numbers in this case can make large differences.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">In terms of acoustic energy, 0 dB-SPL is the threshold of hearing, 60 dB-SPL is the loudness of an average conversation, 120 dB-SPL is known as the threshold of feeling, and 140 dB-SPL is the threshold of pain.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">Lastly, human beings are not sensitive to all frequencies equally. We are much more sensitive to midrange frequencies (about 500hz &#8211; 5khz) than we are high or low frequencies. Therefore, the frequency response of audio can perceptively change when we change its volume.<\/span><\/li>\n<\/ol>\n<\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><strong>Velocity:<\/strong>\n<ol>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">The speed of sound, which is approximately 1,130 feet per second at sea level at a temperature of 70\u00b0 F.\u00a0 This is crucial for live sound in open air environments, but it\u00a0 varies wildly based on a myriad of factors, and is not usually a component of small scale recordings.<\/span><\/li>\n<\/ol>\n<\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\"><strong>Wavelength<\/strong>:<\/span>\n<ol>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">The physical length of sound,\u00a0 which has an inverse relationship to the frequency; high frequencies have much shorter wavelengths than low frequencies. This is useful when considering professional or large scale acoustics.<\/span><\/li>\n<\/ol>\n<\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\"><strong>Phase<\/strong>:<\/span>\n<ol>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">The time relationship between two or more sound waves at a given point in their compression and rarefaction cycles.\u00a0<\/span>\n<ol>\n<li style=\"font-weight: 400;\" aria-level=\"3\"><span style=\"font-weight: 400;\">Two identical sound waves, taken 180\u00b0 out of phase, will cancel out into a null value and produces no sound. This is <\/span><i><span style=\"font-weight: 400;\">destructive interference<\/span><\/i><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"3\"><span style=\"font-weight: 400;\">Two identical sound waves, perfectly in phase, will increase the amplitude of that soundwave. This is known as <\/span><i><span style=\"font-weight: 400;\">constructive interference.<\/span><\/i><\/li>\n<\/ol>\n<\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">If you are recording a single source, such as one voice, phase should not be an issue.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">If you are recording multiple sources simultaneously, simply follow the <\/span><b>3:1 ratio rule, <\/b>which is t<b>hat<\/b><span style=\"font-weight: 400;\"> the distance between microphones should be 3 times the distance to their sources.\u00a0<\/span>\n<ol>\n<li style=\"font-weight: 400;\" aria-level=\"4\"><span style=\"font-weight: 400;\">Example: Two microphones are both 10 centimeters from their vocalists. Therefore, the distance between the two microphones should be at least 30 centimeters to avoid phasing issues.\u00a0<\/span><\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<\/li>\n<\/ul>\n<p style=\"padding-left: 40px;\"><span style=\"font-weight: 400;\">It is important to remember that in reality, every sound we hear is a mixture of different frequencies at different amplitudes in different environments. Therefore, any recording of natural sound will be composed of a wide range of frequencies and harmonics that create the <\/span><b>timbre<\/b><span style=\"font-weight: 400;\"> of that sound. This is how we can detect the difference between a violin and piano, even if they are playing the same note simultaneously.\u00a0<\/span><\/p>\n<hr \/>\n<h3>More<\/h3>\n<p><a href=\"https:\/\/www.electronics-tutorials.ws\/io\/io_8.html\">Analog audio<\/a> &#8212; Electronics tutorials<\/p>\n","protected":false},"excerpt":{"rendered":"<p>By Nick Kovarik\u00a0 Acoustic or natural sound is the propagation of vibrating energy through a medium; typically air. When an object vibrates, the air molecules near it compress and stretch, radiating outwards. This process is called compression and rarefaction.\u00a0 There &hellip; <a href=\"https:\/\/revolutionsincommunication.com\/viscomm\/recording-audio\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":1781,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"full-width-page.php","meta":{"nf_dc_page":"","footnotes":""},"class_list":["post-3495","page","type-page","status-publish","has-post-thumbnail","hentry"],"_links":{"self":[{"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/pages\/3495","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/comments?post=3495"}],"version-history":[{"count":6,"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/pages\/3495\/revisions"}],"predecessor-version":[{"id":3562,"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/pages\/3495\/revisions\/3562"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/media\/1781"}],"wp:attachment":[{"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/media?parent=3495"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}