manual/_manual/17_mixing/02_panning/01_stereo_panner.html

---
layout: default
title: Stereo Panner
---                        

<p>
The default stereo panner distributes 2 inputs to 2 outputs. Its
behaviour is controlled by two parameters, width and position. The
default settings for the stereo panner
are width=100%>, position=center (L=50%,
R=50%). This panner assumes that you have 2 uncorrelated,
independent signals that you wish to distribute to two outputs. 
</p>
<div class="well">
<p>
  With the default values it is not possible to alter the position,
  since the width is already spread entirely across both outputs. To
  alter the position, you must first reduce the width.
</p>
</div>

<h2>Stereo Panner User Interface</h2>

<img src="/images/stereo-panner-annotated.png" alt=""/>

<p>
  The panner user interface consists of 3 elements, divided between
  the top and bottom half. Click and/or drag in the top half to
  control position; click and/or drag in the bottom half to control
  width (see below for details).
<p>
<p>
  In the top half is the position indicator, which shows where the
  center of the stereo image is relative to the left and right
  edges. When this is the middle of the panner, the stereo image is
  centered between the left and right outputs. When it all the way to
  the left, the stereo image collapses to just the left speaker. 
</p>
<p>
  In the bottom half are two signal indicators, one marked "L" and the
  other "R". The distance between these two shows the width of the
  stereo image. If the width is reduced to zero, there will only be a
  single signal indicator marked "M" (for mono), and whose color will
  change to indicate the special state.
</p>

<p>
  It is possible to invert the outputs (see below) so that whatever
  would have gone to the right channel goes to the left and vice
  versa. When this happens, the entire movable part of the panner
  changes color to indicate clearly that this is the case. 
</p>

<h3>Position vs. L/R</h3>

<p>
  Although the implementation of the panner uses the "position"
  parameter, when the user interface displays it numerically, it shows a pair of numbers that
  will be familiar to most audio engineers. 
</p>

<table>
<tr><th>Position</th><th>L/R</th><th>English</th></tr>
<tr><td>0</td><td>L=50% R=50%</td><td>signal image is midway between
    left and right speakers</td></tr>

<tr><td>-1</td><td>L=100% R=0%</td><td>signal image is entirely
    at the left speaker </td></tr>

<tr><td>1</td><td>L=0% R=100%</td><td>signal image is entirely
    at the right speaker</td></tr>
</table>

<p>
One way to remember this sort of convention is that the middle of the
USA is not Kansas, but "Los Angeles: 50% New York: 50%". 
</p>

<h2>Examples In Use</h2>

<table>
<tr><th>Appearance</th><th>Settings</th></tr>
<tr><td><img src="/images/stereo-panner.png"></td><td>Width=100%,
    L=50 R=50</td></tr>
<tr><td><img src="/images/stereo-panner-zero.png"></td><td>Width=0%,
    L=50 R=50</td></tr>
<tr><td><img src="/images/stereo-panner-inverted.png"></td><td>Width=-100%, Position = 0 (center)</td></tr>
<tr><td><img src="/images/stereo-panner-right.png"></td><td>Width=36%,
    L=44 R=56</td></tr>
<tr><td><img src="/images/stereo-panner-hard-right.png"></td><td>Width=0%,
    L=0 R=100</td></tr>
</table>

<h2>Using the mouse</h2>

<p>Mouse operations in the upper half of the panner adjust the position
  parameter, constrained by the current width setting. 
</p>

<p>Mouse operations in the lower half of the panner adjust the width
  parameter, constrained by the current position setting. 
</p>

<p>To change the position smoothly, press the right button and drag
  within the top half of the panner, then release. The position will
  be limited by the current width setting. <em>Note: you do not need
  to grab the position indicator in order to drag</em>
</p>

<p>To change the width smoothly, press the right button and drag
  within the lower half of the panner, then release. The width will be
  limited by the current position setting.<em>Note: you do not need to
  grab the L/R indicators in order to drag</em>
</p>

<dl class="faq">

<dt>Reset to defaults</dt>
<dd>Click <key class="mod3">right button</key></dd>

<dt>Change to a "hard left"</dt>
<dd>Double click <key class="mod2">right button</key> in the upper left half
  of the panner</dd>

<dt>Change to a "hard right"</dt>
<dd>Double click <key class="mod2">right button</key> in the upper right half
  of the panner</dd>

<dt>Move position as far left as possible, given width</dt>
<dd>Double click <key>right button</key> in the upper left half of the
  panner</dd>

<dt>Move position as far right as possible, given width</dt>
<dd>Double click <key>right button</key> in the upper right half of the
  panner</dd>

<dt>Set the position to center</dt>
<dd>Click <key>right button</key> in the upper middle of the panner</dd>

<dt>Reset to maximum possible width</dt>
<dd>Double click <key>right button</key> on the lower left side</dd>

<dt>Invert (flip channel assignments)</dt>
<dd>Double click <key>right button</key> on the lower right side</dd>

<dt>Set width to 0&deg;</dt>
<dd>Double click <key>right button</key> in the lower middle</dd>
</dl>

<h4>Keyboard bindings</h4>

When the pointer is within a stereo panner user interface, the following
keybindings are available to operate on that panner:

<dl>
  <dt><key>&uarr;</key> / <key class="mod1">&uarr;</key></dt>
  <dd>increase width by 1&deg; / 5&deg;</dd>
  <dt><key>&darr;</key> / <key class="mod1">&darr;</key></dt>
  <dd>decrease width by 1&deg; / 5&deg;</dd>
  <dt><key>&larr;</key> / <key class="mod1">&larr;</key></dt>
  <dd>move position 1&deg; / 5&deg; to the left</dd>
  <dt><key>&rarr;</key> / <key class="mod1">&rarr;</key></dt>
  <dd>move position 1&deg / 5&deg; to the right</dd>
  <dt><key>0</key></dt>
  <dd>reset position to center</dd>
  <dt><key class="mod2">&uarr;</key></dt>
  <dd>reset width to 180&deg; (100%)</dd>
</dl>

<h4>Using the scroll wheel/touch scroll</h4>

When the pointer is within a stereo panner user interface, the scroll
wheel may be used as follows:

<dl>
<dt>left / <key class="mod1">left</key></dt>
<dd>increase width by 1&deg; / 5&deg;</dd>

<dt>right / <key class="mod1">right</key></dt>
<dd>decrease width by 1&deg; / 5&deg;</dd>

<dt>up / <key class="mod1">up</key></dt>
<dd>move position 1&deg; / 5&deg; to the left</dd>

<dt>down / <key class="mod1">down</key></dt>
<dd>move position 1&deg; / 5&deg;to the right</dd>
</dl>