{"id":3294,"date":"2014-07-30T10:33:41","date_gmt":"2014-07-30T17:33:41","guid":{"rendered":"http:\/\/www.realhd-audio.com\/?p=3294"},"modified":"2014-07-30T10:33:50","modified_gmt":"2014-07-30T17:33:50","slug":"compression-vs-compression-part-ii","status":"publish","type":"post","link":"https:\/\/www.realhd-audio.com\/?p=3294","title":{"rendered":"Compression vs. Compression? Part II"},"content":{"rendered":"

Take a look at the diagram that I\u2019ve prepared below. It shows a number of things. The first three waveform displays show each stage of compressing a signal. On the left is the uncompressed signal. The wide vertical differences show the short and long term dynamics of the particular piece of music (this is the end of Mosaic again, which is available for download at the FTP site). The middle waveform shows what happens when a 20:1 compressor\/limiter (a limiter is simply an extreme case of compression) is applied. Any part of the sound that exceeds the \u201cthreshold\u201d level is reduced by a specified ratio\u2026in this case 20 to 1, which is a lot. If a signal comes in below the threshold it is allowed to pass through undisturbed.<\/p>\n

\"140730_compression_ii_image\"<\/a><\/p>\n

Figure 1 – Three images of a file subjected to compression and a transfer function showing the input and output from a compressor\/limiter. [Click to enlarge]<\/p>\n

The overall RMS level of the song is reduced and the resulting waveform shows the telltale plateau appearance of most pop music. This is how things are portrayed in \u201cThe Distortion of Sound\u201d film. But the processing doesn\u2019t stop there. <\/p>\n

Not only are the engineers trying to protect their recordings from overages but they are also tasked with making the final output as loud as possible. This additional processing doesn\u2019t happen during the initial recording. It\u2019s the job of the mastering engineer to crank up the amplitude so that the tune \u201cpunches\u201d when played on FM radio, on your iPhone or through your Bluetooth portable speaker.<\/p>\n

It\u2019s not necessarily the best thing for the music but it is standard operating procedure in the commercial music business.<\/p>\n

There are lots of creative uses of compression but normalizing is not one of them. Normalizing happens after the compressor\/limiter brings down the peaks and flattens the waveform\u2026and the dynamics of the music selection. This is the process that boosts the whole track up to the maximum allowed. If you\u2019re using a PCM system at 16-bits, then normalizing will find the loudest instant in your track and amplify it to the 16-bit maximum AND then raise the rest of the track by the same amount. If there are no amplitude differences in the track (which is likely because of the heavy compression that was applied) then the whole track get maxed out.<\/p>\n

That what should have been explained and animated in \u201cThe Distortion of Sound\u201d, but it wasn\u2019t. I don\u2019t know why. When tens of thousands of people see this film online or at the Grammy museum, they\u2019re being misinformed.<\/p>\n","protected":false},"excerpt":{"rendered":"

Take a look at the diagram that I\u2019ve prepared below. It shows a number of things. The first three waveform<\/p>\n","protected":false},"author":2,"featured_media":3296,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[45],"tags":[657,50,40,257,172,57,242,197,672,675,17,1032,246,607,70,640,26,639,651,42,298,251,645,638,637,227,643,606,169,276,59,664,549,347,663,659,673,658,660,661],"class_list":["post-3294","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-dr_aixs_posts","tag-advanced-resolution","tag-aix-records","tag-analog-vs-digital","tag-astell-kern","tag-audio-resolution","tag-audio-specifications","tag-audiophile-mastering","tag-capitol-audiofest","tag-capitol-audiofest-2014","tag-chord","tag-dsd","tag-dvd_audio","tag-geek","tag-harman-kardon","tag-hd-downloads","tag-hd-music","tag-hd-audio","tag-hi-res-audio","tag-hi-res-audio-logo","tag-high-resolution-audio","tag-high-res-music","tag-high-resolution","tag-high-resolution-audio-experience","tag-hires-audio","tag-hires-music","tag-hra","tag-hra-listening-experience","tag-htc-m8","tag-mark-waldrep","tag-mastering","tag-music","tag-music-and-emotion","tag-scott-wilkinson","tag-spectragram","tag-the-distortion-of-sound","tag-uhd-audio","tag-ultra-hd","tag-ultra-hd-audio","tag-ultra-high-definition-audio","tag-ultra-high-resolution-audio"],"_links":{"self":[{"href":"https:\/\/www.realhd-audio.com\/index.php?rest_route=\/wp\/v2\/posts\/3294","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.realhd-audio.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.realhd-audio.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.realhd-audio.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.realhd-audio.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3294"}],"version-history":[{"count":1,"href":"https:\/\/www.realhd-audio.com\/index.php?rest_route=\/wp\/v2\/posts\/3294\/revisions"}],"predecessor-version":[{"id":3297,"href":"https:\/\/www.realhd-audio.com\/index.php?rest_route=\/wp\/v2\/posts\/3294\/revisions\/3297"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.realhd-audio.com\/index.php?rest_route=\/wp\/v2\/media\/3296"}],"wp:attachment":[{"href":"https:\/\/www.realhd-audio.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3294"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.realhd-audio.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3294"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.realhd-audio.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3294"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}