SherbyNet - /page/wikibook/entry.mu

Micron Document

<!DOCTYPE html>

<title>Alignment level</title>

</head>

<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Alignment level</span></span>

</h1>

</header>

</p>

/* start https://en.wikipedia.org/ */

.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}

/* end https://en.wikipedia.org/ */

</style><style data-mw-deduplicate="TemplateStyles:r1248332772">

/* start https://en.wikipedia.org/ */

.mw-parser-output .multiple-issues-text{width:95%;margin:0.2em 0}.mw-parser-output .multiple-issues-text>.mw-collapsible-content{margin-top:0.3em}.mw-parser-output .compact-ambox .ambox{border:none;border-collapse:collapse;background-color:transparent;margin:0 0 0 1.6em!important;padding:0!important;width:auto;display:block}body.mediawiki .mw-parser-output .compact-ambox .ambox.mbox-small-left{font-size:100%;width:auto;margin:0}.mw-parser-output .compact-ambox .ambox .mbox-text{padding:0!important;margin:0!important}.mw-parser-output .compact-ambox .ambox .mbox-text-span{display:list-item;line-height:1.5em;list-style-type:disc}body.skin-minerva .mw-parser-output .multiple-issues-text>.mw-collapsible-toggle,.mw-parser-output .compact-ambox .ambox .mbox-image,.mw-parser-output .compact-ambox .ambox .mbox-imageright,.mw-parser-output .compact-ambox .ambox .mbox-empty-cell,.mw-parser-output .compact-ambox .hide-when-compact{display:none}

/* end https://en.wikipedia.org/ */

</style>

<p>The <b>alignment level</b> in an audio <a href="Signal_chain" title="Signal chain">signal chain</a> or on an <a href="Audio_recording" class="mw-redirect" title="Audio recording">audio recording</a> is a defined anchor point that represents a reasonable or typical level.

</p>

<div class="mw-heading mw-heading2"><h2 id="Analogue">Analogue</h2></div>

<p>In analogue systems, alignment level in <a href="Broadcast" class="mw-redirect" title="Broadcast">broadcast</a> chains is commonly 0 <a href="DBu" class="mw-redirect" title="DBu">dBu</a> (0.775 volts RMS) and in professional audio is commonly <i>0 VU</i> (4 dBu, 1.228 volts RMS). Under normal situations, the 0 VU reference allows for a <a href="Headroom_(audio_signal_processing)" title="Headroom (audio signal processing)">headroom</a> of 18 dB or more above the reference level without significant distortion. This is largely due to the use of slow-responding <a href="VU_meter" title="VU meter">VU meters</a> in almost all analogue professional audio equipment, which, by their design and by specification, respond to an average level, not peak levels.

</p>

<div class="mw-heading mw-heading2"><h2 id="Digital">Digital</h2></div>

<p>In digital systems alignment level commonly is at −18 <a href="DBFS" title="DBFS">dBFS</a> (18 dB below <a href="Digital_full_scale" class="mw-redirect" title="Digital full scale">digital full scale</a>), in accordance with <a href="EBU" class="mw-redirect" title="EBU">EBU</a> recommendations.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> Digital equipment must use peak-reading metering systems to avoid severe digital distortion caused by the signal going beyond digital full scale. 24-bit original or master recordings commonly have an alignment level at −24 dBFS to allow extra headroom, which can then be reduced to match the available headroom of the final medium by <a href="Audio_level_compression" class="mw-redirect" title="Audio level compression">audio level compression</a>. FM broadcasts usually have only 9 dB of headroom, as recommended by the EBU, but digital broadcasts, which could operate with 18 dB of headroom, given their low noise floor even in difficult reception areas, currently operate in a state of confusion, with some transmitting at maximum level, while others operate at a much lower level, even though they carry material that has been compressed for compatibility with the lower dynamic range of FM transmissions.

</p>

<p>In EBU documents <i>alignment level</i> defines −18 dBFS as the level of the <i>alignment signal</i>, a 1 kHz sine tone for analog applications and 997 Hz in digital applications.

</p>

<div class="mw-heading mw-heading2"><h2 id="Motivation">Motivation</h2></div>

<p>Using alignment level rather than <a href="Maximum_permitted_level" class="mw-redirect" title="Maximum permitted level">maximum permitted level</a> as the reference point allows more sensible headroom management throughout the audio signal chain; <a href="Audio_level_compression" class="mw-redirect" title="Audio level compression">compression</a> happens only where intended.

</p><p><a href="Loudness_war" title="Loudness war">Loudness wars</a> have resulted in increasing playback loudness. <a href="Loudness_normalisation" class="mw-redirect" title="Loudness normalisation">Loudness normalisation</a> to a fixed alignment level can improve the experience when listening to mixed material.

</p>

<ul><li><a href="Audio_normalization" title="Audio normalization">Audio normalization</a></li>

<li><a href="Full_scale" title="Full scale">Full scale</a></li>

<li><a href="Nominal_level" title="Nominal level">Nominal level</a></li>

<li><a href="Transmission-level_point" class="mw-redirect" title="Transmission-level point">Transmission-level point</a></li></ul>

<div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div>

<ul><li><a rel="nofollow" class="external text" href="http://tech.ebu.ch/docs/r/r128.pdf">EBU Recommendation R128 - Loudness normalisation and permitted maximum level of audio levels (2010)</a></li>

<li><a rel="nofollow" class="external text" href="http://tech.ebu.ch/docs/r/r068.pdf">EBU Recommendation R68-2000</a></li>

<li><a rel="nofollow" class="external text" href="http://tech.ebu.ch/docs/r/r117.pdf">EBU Recommendation R117-2006</a> (against <a href="Loudness_war" title="Loudness war">loudness war</a>)</li>

<li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20080308193128/http://www.irt.de/IRT/FuE/as/pdf/AES2002OnLevelling.pdf">AES Convention Paper 5538 On Levelling and Loudness Problems at Broadcast Studios</a></li>

<li><a rel="nofollow" class="external text" href="http://www.ebu.ch/CMSimages/en/tec_doc_t3282_tcm6-10542.pdf">EBU Tech 3282-E on EBU RDAT Tape Levels</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20090909130542/http://www.ebu.ch/CMSimages/en/tec_doc_t3282_tcm6-10542.pdf">Archived</a> 2009-09-09 at the <a href="Wayback_Machine" title="Wayback Machine">Wayback Machine</a></li>

<li><a rel="nofollow" class="external text" href="http://www.ebu.ch/CMSimages/en/tec_text_r89-1997_tcm6-4703.pdf">EBU R89-1997 on CD-R levels</a></li>

<li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20060617172836/http://www.tcelectronic.com/media/lund_2004_distortion_tmt20.pdf">Distortion to the People — TC Electronics</a></li>

<li><a rel="nofollow" class="external text" href="http://tech.ebu.ch/groups/ploud">EBU Loudness Group</a></li></ul>

/* start https://en.wikipedia.org/ */

.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("./mw/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("./mw/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("./mw/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("./mw/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}

/* end https://en.wikipedia.org/ */

</style><cite class="citation journal cs1"><a rel="nofollow" class="external text" href="https://tech.ebu.ch/docs/r/r068.pdf">"EBU Technical Recommendation R68-2000 - Alignment level in digital audio production equipment and in digital audio recorders"</a> <span class="cs1-format">(PDF)</span>. <i>EBU Recommendations</i>. <a href="European_Broadcasting_Union" title="European Broadcasting Union">European Broadcasting Union</a>. 2000. <q>The EBU recommends that, in digital audio equipment, its Members should use coding levels for digital audio signals which correspond to an alignment level which is 18 dB below the maximum possible coding level of the digital system, irrespective of the total number of bits available.</q></cite></span>

</li>

</ol></div></div><div><div class="zim-footer">

This article is issued from <a class="external text" title="Last edited on 2025-05-23" href="https://en.wikipedia.org/wiki/?title=Alignment_level&oldid=1291737857">Wikipedia</a>. The text is available under <a class="external text" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en">Creative Commons Attribution-Share Alike 4.0</a> unless otherwise noted. Additional terms may apply for the media files.

</div>

</div></div>

</div>

</main>

</div>

</body></html>