198 lines
9.1 KiB
HTML
198 lines
9.1 KiB
HTML
<p>
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The <em>Loudness Analyzer and Normalizer</em> tool is useful at the
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end of the mixing process to make the final audio file comply with
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different specs regarding loudness.
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</p>
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<p class="note">
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This is a rather advanced mode. When using the <em>Loudness Analyzer &
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Normalizer</em> (or <dfn>LAN</dfn>), one has to make sure than normalization
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is disabled when exporting.
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<br><br>
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In general, it is recommended to just use <a href="@@export-format-profiles">
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automatic export normalization</a>, in the <a href="@@export-dialog">Export
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dialog</a>. This can also produce results for multiple targets at the
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same time.
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</p>
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<p>
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It is enabled by checking
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<kbd class="option">Enable master-bus output gain control</kbd> in the
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<a href="@@preferences#preferences-signal_flow">Preferences</a>.
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The <a href="@@master-bus-strip">Master Bus strip</a> then shows a <kbd class="menu">LAN</kbd>
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button to start the analysis, and a volume slider that is the global gain
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that can be set either manually or by the loudness normalizer.
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</p>
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<p>
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The LAN can also be started from the <kbd class="menu">Session > Loudness
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assistant…</kbd> menu. If the option above is not enabled, Ardour
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will link to the relevant page of the Preferences.
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</p>
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<p>Either method show the following window:</p>
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<figure>
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<img src="/images/pre_loudness.png"
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alt="The Loudness Analyzer realtime selector"
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width="50%" >
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<figcaption>
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The Loudness Analyzer realtime selector
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</figcaption>
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</figure>
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<p>
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This window allows to start the loudness analysis. A choice is offered
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between freewheeling (i.e. Ardour renders the session as fast as possible
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to measure the loudness), by default, or Realtime, for cases where freewheeling would
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not accurately render the session, e.g. if a hardware or JACK effect
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is used in the session, by clicking on the <kbd class="menu">Realtime</kbd>
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toggle button.
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</p>
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<p>
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After the analysis is over, the Loudness Analyzer and Normalizer is shown:
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</p>
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<figure>
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<img
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src="/images/loudness_analyzer.png"
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alt="The Loudness Analyzer and Normalizer"
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width="75%" >
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<figcaption>
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The Loudness Analyzer and Normalizer
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</figcaption>
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</figure>
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<h2 id="loudness-graph">The Loudness Graph</h2>
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<p>
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At the top of the window, a loudness graph visually represents the
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analysis. The x-axis represents the time, and the y-axis represents
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the perceived loudness in <abbr title="Loudness Units referenced to
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Full Scale">LUFS</abbr>:
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</p>
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<ul>
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<li><span style="color:green;">Integrated loudness</span> averaging the loudness on the whole session</li>
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<li><span style="color:red;">Short loudness</span> using a sliding time window of 3 seconds</li>
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<li><span style="color:blue;">Momentary loudness</span> using a sliding time window of 400 ms.</li>
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</ul>
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<h2 id="normalization-parameters">Normalization Parameters</h2>
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<p>
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As loudness is a perceived sonic energy, and depends on the level, frequency,
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duration and nature of the sound, this window allows to base the calculation
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of the loudness normalization on different parameters :
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</p>
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<ul>
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<li><dfn>Peak :</dfn> is the highest signal level value</li>
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<li><dfn>True Peak :</dfn> is the highest signal level value where the
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signal has been oversampled to figure out more in-between values
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between the samples (interpolation)</li>
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<li><dfn>Integrated Loudness :</dfn> is the loudness computed from the
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whole session or range</li>
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<li><dfn>Max Short Loudness :</dfn> is the maximum loudness computed
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on short time ranges (3 seconds)</li>
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<li><dfn>Max Momentary Loudness :</dfn> is the maximum momentary loudness</li>
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</ul>
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<p>
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Any combination of these parameters can be taken into account when determining
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the gain normalization, by checking its momentary button, and setting a
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<em>Target</em> value.
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</p>
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<p>
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Ardour shows both the <em>Measured</em> value of the parameters, and the
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<em>Delta</em> value, i.e. the difference between the <em>Target</em>
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and <em>Measured</em> values, hence the gain correction.
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</p>
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<p>
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The maximum <em>Delta</em> value is the Gain correction to apply to fit
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all the Target values.
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</p>
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<p>
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Ardour shows, under the parameters, a summary of the calculation :
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</p>
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<ul>
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<li><dfn>Gain to normalize:</dfn> is the max <em>Delta</em> value</li>
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<li><dfn>Previous output gain:</dfn> is the current Master track gain</li>
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<li><dfn>Total Gain:</dfn> is the difference between these two values,
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hence the correction to apply</li>
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</ul>
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<h2 id="presets">Presets</h2>
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<p>
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A selection of presets is offered to simplify the normalization. These
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presets apply the relevant parameters and their target values. Below
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is a table of these presets:
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</p>
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<table>
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<thead>
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<tr><th>Parameter name: </th><th>dbFS </th><th>dBTP </th><th>LUFS </th><th>short</th><th>mom. </th><th>FS</th><th>TP </th><th>int</th><th>sht </th><th>mom</th><th>maxIntg</th><th>notes</th></tr>
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</thead>
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<tbody>
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<tr><th>EBU R128 </th><td>false</td><td> true</td><td> true</td><td>false</td><td>false</td><td> 0</td><td>-1.0</td><td>-23</td><td> 0</td><td> 0</td><td>-22.5</td><td> -23.5</td></tr>
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<tr><th>EBU R128 S1 </th><td>false</td><td> true</td><td> true</td><td> true</td><td>false</td><td> 0</td><td>-1.0</td><td>-23</td><td>-18</td><td> 0</td><td>-22.5</td><td> -23.5</td></tr>
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<tr><th>ATSC A/85 </th><td>false</td><td> true</td><td> true</td><td> true</td><td>false</td><td> 0</td><td>-2.0</td><td>-24</td><td> 0</td><td> 0</td><td>-22.0</td><td> -26.0</td></tr>
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<tr><th>AES Streaming </th><td>false</td><td> true</td><td> true</td><td>false</td><td>false</td><td> 0</td><td>-1.0</td><td>-18</td><td> 0</td><td> 0</td><td>-16.0</td><td> -20.0</td></tr>
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<tr><th>ASWG-R001 HOME </th><td>false</td><td> true</td><td> true</td><td> true</td><td>false</td><td> 0</td><td>-1.0</td><td>-24</td><td> 0</td><td> 0</td><td>-22.0</td><td> -26.0</td></tr>
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<tr><th>Digital Peak </th><td> true</td><td>false</td><td>false</td><td>false</td><td>false</td><td> 0</td><td> 0.0</td><td> 0</td><td> 0</td><td> 0</td><td> 0.0</td><td>-200.0</td></tr>
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<tr><th>CD/DVD </th><td> true</td><td> true</td><td> true</td><td>false</td><td>false</td><td> 0</td><td>-0.1</td><td> -9</td><td> 0</td><td> 0</td><td> 0.0</td><td>-200.0</td></tr>
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<tr><th>Amazon Music </th><td>false</td><td> true</td><td> true</td><td>false</td><td>false</td><td> 0</td><td>-2.0</td><td>-14</td><td> 0</td><td> 0</td><td> -9.0</td><td> -19.0</td></tr>
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<tr><th>Apple Music </th><td>false</td><td> true</td><td> true</td><td>false</td><td>false</td><td> 0</td><td>-1.0</td><td>-16</td><td> 0</td><td> 0</td><td>-15.0</td><td> -17.0</td></tr>
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<tr><th>Deezer </th><td>false</td><td> true</td><td> true</td><td>false</td><td>false</td><td> 0</td><td>-1.0</td><td>-15</td><td> 0</td><td> 0</td><td>-14.0</td><td> -16.0</td></tr>
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<tr><th>Soundcloud </th><td>false</td><td> true</td><td> true</td><td>false</td><td>false</td><td> 0</td><td>-1.0</td><td>-10</td><td> 0</td><td> 0</td><td> -8.0</td><td> -13.0</td></tr>
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<tr><th>Spotify </th><td>false</td><td> true</td><td> true</td><td>false</td><td>false</td><td> 0</td><td>-1.0</td><td>-14</td><td> 0</td><td> 0</td><td> -8.0</td><td> -20.0</td></tr>
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<tr><th>Spotify Loud </th><td>false</td><td> true</td><td> true</td><td>false</td><td>false</td><td> 0</td><td>-2.0</td><td>-11</td><td> 0</td><td> 0</td><td> -5.0</td><td> -17.0</td></tr>
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<tr><th>Youtube </th><td>false</td><td> true</td><td> true</td><td>false</td><td>false</td><td> 0</td><td>-1.0</td><td>-14</td><td> 0</td><td> 0</td><td>-13.0</td><td> -15.0</td></tr>
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</tbody>
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</table>
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<p>
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New presets can be created at will and saved/removed using the <kbd>Save</kbd>
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and <kbd>Remove</kbd> buttons next to the preset choice. The Standard
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presets listed above can not be removed or edited.
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</p>
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<p>
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The <kbd>Analysis Report</kbd> button allows to visually represent
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the analysis with a graph in a very similar window to the one in the
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Post-<a href="@@export-dialog">Export</a> analysis.
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</p>
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<figure>
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<img
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src="/images/export-loudness-report.png"
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alt="The loudness report"
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width="75%" >
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<figcaption>
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The loudness report
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</figcaption>
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</figure>
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<h2 id="conformity-analysis-panel">The Conformity Analysis Panel</h2>
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<p>
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At the lower right end of the window is a <em>Conformity Analysis</em>
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info panel indicating, for each of the presets above, if the corrected
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gain would fit the required values:
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</p>
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<ul>
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<li><span style="color:red;">✖</span>: the signal is too loud</li>
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<li><span style="color:orange;">✔</span>: the signal is too quiet, but satisfies the max. loudness spec</li>
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<li><span style="color:green;">✔</span>: signal loudness is within the spec.</li>
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</ul>
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<p>
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Lastly, the gain correction is, by default, applied after all the processors
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of the master bus. This can also be changed, either by checking the
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<kbd>Custom Amplifier Position</kbd> temporaty button in this window, or in the Master
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strip, by <kbd class="mouse">Right</kbd>-clicking the gain slider and
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checking <kbd class="option">Custom LAN Amp Position</kbd>. The gain
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normalizer then becomes a processor in the processors box of the Master
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strip, that can be moved as needed like any processor/effect.
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</p>
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