X-Git-Url: http://shamusworld.gotdns.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;ds=sidebyside;f=include%2Fstereo-panner.html;h=60ded644bd6c2d278377961f195419d3b6c0aee4;hb=a26b49e5c69ac38d5465c62623994e8a81f1b6b3;hp=35fd4ab87a753efdd3ccaf1dd3cb87623d54129b;hpb=7a4c28bd8605e90876ebee619de364ab7001e405;p=ardour-manual
diff --git a/include/stereo-panner.html b/include/stereo-panner.html
index 35fd4ab..60ded64 100644
--- a/include/stereo-panner.html
+++ b/include/stereo-panner.html
@@ -5,25 +5,30 @@
position. By default, the panner is centered at full width.
- 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
mono-compatible, such as a co-incident microphone recording, or a
sound stage that has been created with pan pots.*
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.
Stereo Panner User Interface
-
+
+
The panner user interface 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).
@@ -34,11 +39,11 @@
the left, the stereo image collapses to just the left speaker.
- 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 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), whose color will
- change to indicate the special state.
+ single signal indicator marked M (for mono), whose color will
+ change to indicate this special state.
It is possible to invert the outputs (see below) so that whatever
@@ -55,14 +60,12 @@
a pair of numbers that will be familiar to most audio engineers.
-
+
Position
L/R
English
0
L=50% R=50%
signal image is midway between
left and right speakers
-
-1
L=100% R=0%
signal image is entirely
at the left speaker
-
1
L=0% R=100%
signal image is entirely
at the right speaker
@@ -74,7 +77,7 @@
Examples In Use
-
+
Appearance
Settings
Width=100%,
L=50 R=50
@@ -98,51 +101,51 @@
parameter, constrained by the current position setting.
- 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. 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. Note: it is not necessary
to grab the position indicator in order to drag.
- 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. Note: you do not need to
- grab the L/R indicators in order to drag.
+ 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. Note: it is not necessary
+ to grab the L/R indicators in order to drag.
-
+
-
Reset to defaults
-
Click right
+
Reset to defaults
+
Click right
-
Change to hard left
-
Double click right in the upper left half
- of the panner
+
Change to hard left
+
Double click right in the upper left half
+ of the panner
-
Change to a hard right
-
Double click right in the upper right half
- of the panner
+
Change to a hard right
+
Double click right in the upper right half
+ of the panner
-
Move position as far left as possible, given width
-
Double click right in the upper left half of the
- panner
+
Move position as far left as possible, given width
+
Double click right in the upper left half of the
+ panner
-
Move position as far right as possible, given width
-
Double click right in the upper right half of the
- panner
+
Move position as far right as possible, given width
+
Double click right in the upper right half of the
+ panner
-
Set the position to center
-
Click right in the upper middle of the panner
+
Set the position to center
+
Click right in the upper middle of the panner
-
Reset to maximum possible width
-
Double click right on the lower left side
+
Reset to maximum possible width
+
Double click right on the lower left side
-
Invert (flip channel assignments)
-
Double click right on the lower right side
+
Invert (flip channel assignments)
+
Double click right on the lower right side
-
Set width to 0°
-
Double click right in the lower middle
-
+
Set width to 0°
+
Double click right in the lower middle
+
Keyboard bindings
@@ -151,20 +154,20 @@
keybindings are available to operate on that panner:
-
-
↑ / ↑
-
increase width by 1° / 5°
-
↓ / ↓
-
decrease width by 1° / 5°
-
← / ←
-
move position 1° / 5° to the left
-
→ / →
-
move position 1° / 5° to the right
-
0
-
reset position to center
-
↑
-
reset width to full (100%)
-
+
+
↑ / ↑
+
increase width by 1° / 5°
+
↓ / ↓
+
decrease width by 1° / 5°
+
← / ←
+
move position 1° / 5° to the left
+
→ / →
+
move position 1° / 5° to the right
+
0
+
reset position to center
+
↑
+
reset width to full (100%)
+
Using the scroll wheel/touch scroll
@@ -173,16 +176,16 @@
wheel may be used as follows:
-
-
⇐ / ⇐
-
increase width by 1° / 5°
-
⇒ / ⇒
-
decrease width by 1° / 5°
-
⇑ / ⇑
-
move position 1° / 5° to the left
-
⇓ / ⇓
-
move position 1° / 5°to the right
-
+
+
⇐ / ⇐
+
increase width by 1° / 5°
+
⇒ / ⇒
+
decrease width by 1° / 5°
+
⇑ / ⇑
+
move position 1° / 5° to the left
+
⇓ / ⇓
+
move position 1° / 5°to the right
+
Stereo panning caveats
@@ -190,12 +193,12 @@
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.
-When you reduce the with, you are effectively summing two highly
-correlated signals with a delay, which will cause comb filtering.
+When the width is reduced, two highly correlated signals with a delay are
+effectively summed, which will cause comb filtering.
-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.
For testing, we apply a pink noise signal to both inputs of an Ardour stereo
@@ -205,40 +208,52 @@ straight line, which would indicate that our signal chain does not color the
sound:
-
+
- 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.
-Recall that an ORTF 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 ORTF 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).
-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:
-
+
+
+
-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.
-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 advised to listen carefully for artefacts when manipulating unknown stereo
+ signals—many orchestra sample libraries for example do contain
+ time-delay components.