<dfn>position</dfn>. By default, the panner is centered at full width.
</p>
<p>
- The stereo panner assumes that the signals
- you wish to distribute are either uncorrelated (i.e. totally
- independent), or that they contain a stereo image which is
+ The stereo panner assumes that the signals to distribute are either uncorrelated
+ (i.e. totally independent), or that they contain a stereo image which is
<dfn>mono-compatible</dfn>, such as a co-incident microphone recording, or a
sound stage that has been created with pan pots.<sup><a href="#caveat">*</a></sup>
</p>
<p class="note">
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.
+ alter the position, the width must first be reduced.
</p>
<h2>Stereo Panner User Interface</h2>
<p>
The <dfn>panner user interface</dfn> consists of three 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
+ the top and bottom half. Clicking and/or dragging in the top half
+ controls position; clicking and/or dragging in the bottom half controls
width (see below for details).
</p>
<p>
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
+ In the bottom half are two signal indicators, one marked <kbd class="menu">L</kbd> and the
+ other <kbd class="menu">R</kbd>. 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), whose color will
- change to indicate the special state.
+ single signal indicator marked <kbd class="menu">M</kbd> (for mono), whose color will
+ change to indicate this special state.
</p>
<p>
It is possible to invert the outputs (see below) so that whatever
<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>
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
+ The position can be changed smoothly, by pressing the right button and dragging
+ within the top half of the panner, then releasing. The position will
+ be limited by the current width setting. <em>Note: it is not necessary
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>
+ The width can also be changed smoothly, by pressing the right button and dragging
+ within the lower half of the panner, then releasing. The width will be
+ limited by the current position setting. <em>Note: it is not necessary
+ to grab the L/R indicators in order to drag.</em>
</p>
<table class="dl">
<tr><th><kbd>←</kbd> / <kbd class="mod1">←</kbd></th>
<td>move position 1° / 5° to the left</td></tr>
<tr><th><kbd>→</kbd> / <kbd class="mod1">→</kbd></th>
- <td>move position 1° / 5° to the right</td></tr>
+ <td>move position 1° / 5° to the right</td></tr>
<tr><th><kbd>0</kbd></th>
<td>reset position to center</td></tr>
<tr><th><kbd class="mod2">↑</kbd></th>
The stereo panner will introduce unwanted side effects on
material that includes a time difference between the channels, such
as A/B, ORTF or NOS microphone recordings, or delay-panned mixes.<br>
-When you reduce the with, you are effectively summing two highly
-correlated signals with a delay, which will cause <dfn>comb filtering</dfn>.
+When the width is reduced, two highly correlated signals with a delay are
+effectively summed, which will cause <dfn>comb filtering</dfn>.
</p>
<p>
-Let's take a closer look at what happens when you record a source at 45° to the
-right side with an ORTF stereo microphone array and then manipulate the width.
+Let's take a closer look at what happens when a source is recorded at 45° to the
+right side with an ORTF stereo microphone array and then the width manipulated.
</p>
<p>
For testing, we apply a <dfn>pink noise</dfn> signal to both inputs of an Ardour stereo
sound:
</p>
-<img src="/images/stereo-panner-with-ORTF-fullwidth.png" />
+<figure class="center">
+ <img src="/images/stereo-panner-with-ORTF-fullwidth.png" alt="Stereo panner
+ with ORTF fullwidth">
+ <figcaption>Stereo panner with ORTF full width</figcaption>
+</figure>
<p>
- To simulate an ORTF, we use Robin Gareus' stereo balance control LV2 to set the level difference and time delay. Ignore the Trim/Gain—its purpose is just to align the test signal with the 0dB line of the analyser.
+ An ORTF is simulated using Robin Gareus' stereo balance control LV2 to set the
+ level difference and time delay. The Trim/Gain can be ignored—its purpose
+ is just to align the test signal with the 0dB line of the analyser.
</p>
<p>
-Recall that an <dfn>ORTF</dfn> microphone pair consists of two cardioids spaced 17 cm
-apart, with an opening angle of 110°.
-For a far source at 45° to the right, the time difference between the capsules
-is 350 μs or approximately 15 samples at 44.1 kHz. The level difference
-due to the directivity of the microphones is about 7.5 dB (indicated by the
-distance between the blue and red lines in the analyser).
+ An <dfn>ORTF</dfn> microphone pair consists of two cardioids spaced 17 cm
+ apart, with an opening angle of 110°. For a far source at 45° to the
+ right, the time difference between the capsules is 350 μs or
+ approximately 15 samples at 44.1 kHz. The level difference due to the
+ directivity of the microphones is about 7.5 dB (indicated by the distance
+ between the blue and red lines in the analyser).
</p>
<p>
-Now for the interesting part: if we reduce the width of the signal to 50%,
-the time-delayed signals will be combined in the panner. Observe what
-happens to the frequency response of the left and right outputs:
+ Now for the interesting part: if the width of the signal is reduced to 50%,
+ the time-delayed signals will be combined in the panner. What happens to the
+ frequency response of the left and right outputs is shown in the following
+ picture:
</p>
-<img src="/images/stereo-panner-with-ORTF-halfwidth.png" />
+
+<figure class="center">
+ <img src="/images/stereo-panner-with-ORTF-halfwidth.png" alt="Stereo panner
+ with ORTF halfwidth">
+ <figcaption>Stereo panner with ORTF half width</figcaption>
+</figure>
+
<p>
-You may argue that all spaced microphone recordings will undergo comb
-filtering later, when the two channels recombine in the air between the speakers.
-Perceptually however, there is a huge of difference: our hearing system is
-very good at eliminating comb filters in the real world, where their component
-signals are spatially separated. But once you combine them
-inside your signal chain, this spatial separation is lost and the brain will
-no longer be able to sort out the timbral mess. As usual, you
-get to keep the pieces.
+ It can be argued that all spaced microphone recordings will undergo comb
+ filtering later, when the two channels recombine in the air between the
+ speakers. Perceptually however, there is a huge difference: our hearing
+ system is very good at eliminating comb filters in the real world, where their
+ component signals are spatially separated. But once they are combined inside
+ a signal chain, this spatial separation is lost and the brain will no
+ longer be able to sort out the timbral mess.
</p>
<p class="note">
-Depending on your material and on how much you need to manipulate the width,
-some degree of comb filtering may be acceptable. Then again, it may not. Listen
-carefully for artefacts if you manipulate unknown stereo signals—many
-orchestra sample libraries for example do contain time-delay components.
+ Depending on the material and on how much the width needs to be manipulated,
+ some degree of comb filtering may be acceptable. Then again, it may not.
+ It is advides to listen carefully for artefacts when manipulating unknown stereo
+ signals—many orchestra sample libraries for example do contain
+ time-delay components.
</p>
-
projects / ardour-manual / commitdiff
