Revision 663711 of ConvolverNode

<p>{{ APIRef() }}</p>
<p>The <code>ConvolverNode</code> interface is an&nbsp;{{domxref("AudioNode")}} that&nbsp;performs a Linear Convolution on a given {{domxref("AudioBuffer")}}, often used to achieve a reverb effect. A <code>ConvolverNode</code> always has exactly one input and one output.</p>
<div class="note">
 <p><strong>Note</strong>: For more information on the theory behind Linear Convolution, see the W3C Web Audio API spec section, <a href="https://webaudio.github.io/web-audio-api/#linear-effects-using-convolution">Linear Effects Using Convolution</a>, or read the The <a href="https://en.wikipedia.org/wiki/Linear_convolution">Wikipedia Linear Convolution Article</a>.</p>
</div>
<ul class="audionodebox">
 <li><dfn>Number of inputs</dfn> <code>1</code></li>
 <li><dfn>Number of outputs</dfn> <code>1</code></li>
 <li><dfn>Channel count mode</dfn> <code>"clamped-max"</code></li>
 <li><dfn>Channel count</dfn> <code>2</code></li>
 <li><dfn>Channel interpretation</dfn> <code>"speakers"</code></li>
</ul>
<h2 id="Properties">Properties</h2>
<p><em>Inherits properties from its parent, </em><em>{{domxref("AudioNode")}}</em>.</p>
<dl>
 <dt>
  {{domxref("ConvolverNode.buffer")}}</dt>
 <dd>
  <span>A mono, stereo, or 4-channel&nbsp;</span><em>{{domxref("AudioBuffer")}}</em><span>&nbsp;containing the (possibly multichannel) impulse response used by the <code>ConvolverNode</code> to create the reverb effect. This is normally a simple recording of as-close-to-an-impulse as can be found in the space you want to model. For example, if you want to model the reverb in your bathroom, you might set up a microphone near the door to record the sound of a balloon pop or synthesized impulse from the sink. That audio recording could then used as the buffer.<br />
  This&nbsp;</span><em>{{domxref("AudioBuffer")}}</em><span>&nbsp;must have the same sample-rate as the <code>AudioContext</code> or an exception will be thrown. At the time when this attribute is set, the buffer and the state of the attribute will be used to configure the <code>ConvolverNode</code> with this impulse response having the given normalization. The initial value of this attribute is <code>null</code>.</span></dd>
 <dt>
  {{domxref("ConvolverNode.normalize")}}</dt>
 <dd>
  <span>Controls whether the impulse response from the buffer will be scaled by an equal-power normalization when the buffer attribute is set. Its default value is <code>true</code> in order to achieve a more uniform output level from the convolver, when loaded with diverse impulse responses. If normalize is set to <code>false</code>, then the convolution will be rendered with no pre-processing/scaling of the impulse response. Changes to this value do not take effect until the next time the <code>buffer</code> attribute is set.</span></dd>
</dl>
<h2 id="Methods">Methods</h2>
<p><em>No specific method; inherits methods from its parent, </em><em>{{domxref("AudioNode")}}</em>.</p>
<h2 id="Examples">Example</h2>
<p>{{page("/en-US/docs/Web/API/AudioContext.createConvolver","Example")}}</p>
<h2 id="Specifications">Specifications</h2>
<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
  <tr>
   <td>{{SpecName('Web Audio API', '#the-convolvernode-interface', 'ConvolverNode')}}</td>
   <td>{{Spec2('Web Audio API')}}</td>
   <td>&nbsp;</td>
  </tr>
 </tbody>
</table>
<h2 id="Browser_compatibility">Browser compatibility</h2>
<div>
 {{CompatibilityTable}}</div>
<div id="compat-desktop">
 <table class="compat-table">
  <tbody>
   <tr>
    <th>Feature</th>
    <th>Chrome</th>
    <th>Firefox (Gecko)</th>
    <th>Internet Explorer</th>
    <th>Opera</th>
    <th>Safari (WebKit)</th>
   </tr>
   <tr>
    <td>Basic support</td>
    <td>{{CompatChrome(10.0)}}{{property_prefix("webkit")}}</td>
    <td>{{CompatGeckoDesktop(25.0)}}&nbsp;</td>
    <td>{{CompatNo}}</td>
    <td>15.0{{property_prefix("webkit")}}<br />
     22 (unprefixed)</td>
    <td>6.0{{property_prefix("webkit")}}</td>
   </tr>
  </tbody>
 </table>
</div>
<div id="compat-mobile">
 <table class="compat-table">
  <tbody>
   <tr>
    <th>Feature</th>
    <th>Android</th>
    <th>Firefox Mobile (Gecko)</th>
    <th>Firefox OS</th>
    <th>IE Mobile</th>
    <th>Opera Mobile</th>
    <th>Safari Mobile</th>
    <th>Chrome for Android</th>
   </tr>
   <tr>
    <td>Basic support</td>
    <td>{{CompatUnknown}}</td>
    <td>26.0</td>
    <td>1.2</td>
    <td>{{CompatUnknown}}</td>
    <td>{{CompatUnknown}}</td>
    <td>{{CompatUnknown}}</td>
    <td>33.0</td>
   </tr>
  </tbody>
 </table>
</div>
<h2 id="See_also">See also</h2>
<ul>
 <li><a href="/en-US/docs/Web_Audio_API/Using_Web_Audio_API">Using the Web Audio API</a></li>
</ul>