---
title: GainNode
slug: Web/API/GainNode
translation_of: Web/API/GainNode
---
<p>{{ APIRef("Web Audio API") }}</p>

<div>
<p><code>GainNode</code> 介面代表的是音量改變。 這是 {{domxref("AudioNode")}} 音訊處理模組，可以對輸入的訊號做增益 (gain) 後輸出。一個 <code>GainNode</code> 有一個輸入和一個輸出，兩者有相同的聲道數。</p>
</div>

<p>增益 (gain) 是無單位的數值，隨時間變化，會用來和所有輸入聲道的取樣做相乘。 如果更改的話，新的增益會用 de-zippering 演算法處理，以避免輸出聲音出現難聽的「喀」聲。</p>

<p><img alt="The GainNode is increasing the gain of the output." src="https://mdn.mozillademos.org/files/5085/WebAudioGainNode.png" style="height: 116px; width: 774px;"></p>

<table class="properties">
 <tbody>
  <tr>
   <th scope="row">Number of inputs</th>
   <td><code>1</code></td>
  </tr>
  <tr>
   <th scope="row">Number of outputs</th>
   <td><code>1</code></td>
  </tr>
  <tr>
   <th scope="row">Channel count mode</th>
   <td><code>"max"</code></td>
  </tr>
  <tr>
   <th scope="row">Channel count</th>
   <td><code>2</code> (not used in the default count mode)</td>
  </tr>
  <tr>
   <th scope="row">Channel interpretation</th>
   <td><code>"speakers"</code></td>
  </tr>
 </tbody>
</table>

<h2 id="Constructor">Constructor</h2>

<dl>
 <dt>{{domxref("GainNode.GainNode", "GainNode()")}}</dt>
 <dd>Creates a new instance of an GainNode object.</dd>
</dl>

<h2 id="Properties">Properties</h2>

<p><em>Inherits properties from its parent, </em><em>{{domxref("AudioNode")}}</em>.</p>

<dl>
 <dt>{{domxref("GainNode.gain")}} {{readonlyinline}}</dt>
 <dd>是 <a href="/en-US/docs/Web/API/AudioParam#a-rate">a-rate</a> {{domxref("AudioParam")}} ，代表增益值</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="Example">Example</h2>

<p>{{page("/en-US/docs/Web/API/AudioContext.createGain","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-gainnode-interface', 'GainNode')}}</td>
   <td>{{Spec2('Web Audio API')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</h2>

{{Compat("api.GainNode")}}

<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>