From: Jörn Nettingsmeier Date: Sat, 1 Feb 2014 14:17:57 +0000 (+0100) Subject: s/180deg/full width. 180 makes no sense for stereo. X-Git-Url: http://shamusworld.gotdns.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=25ea2abdb17253dae98fca5c904e3e4399b35ab7;p=ardour-manual s/180deg/full width. 180 makes no sense for stereo. --- diff --git a/_manual/17_mixing/02_panning/01_stereo_panner.html b/_manual/17_mixing/02_panning/01_stereo_panner.html index d17e45e..81af117 100644 --- a/_manual/17_mixing/02_panning/01_stereo_panner.html +++ b/_manual/17_mixing/02_panning/01_stereo_panner.html @@ -7,9 +7,10 @@ title: Stereo Panner 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. + position=center (L=50%, R=50%). This panner assumes that the signals + you wish to distribute are either uncorrelated (that means totally + independent), or they contain a stereo image which is + mono-compatible*.

@@ -43,7 +44,6 @@ title: Stereo Panner single signal indicator marked "M" (for mono), and whose color will change to indicate the special state.

-

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 @@ -97,19 +97,16 @@ title: Stereo Panner Mouse operations in the upper half of the panner adjust the position parameter, constrained by the current width setting.

-

Mouse operations in the lower half of the panner adjust the width 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 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 @@ -170,7 +167,7 @@ title: Stereo Panner

0
reset position to center
↑
-
reset width to 180° (100%)
+
reset width to full (100%)

Using the scroll wheel/touch scroll

@@ -193,3 +190,41 @@ title: Stereo Panner
down / down
move position 1° / 5°to the right
+ +

Panning caveats

+ +

+Note that the stereo panner will introduce unwanted side effects on +material that includes a time difference between the channels, such +as AB, ORTF or NOS microphone recordings, or delay-panned mixes.
+With such signals, when you reduce the with, you are summing two signals +with different delays, which will introduce comb filtering. +

+

+Let's take a look at what happens when you record a source at 45° to the +right side with an ORTF array (cardioids, spacing 17cm, opening angle +110°):
+The time difference is 350 usecs or approximately 15 samples at 44k1. The +level difference due to the directivity of the microphones is about 7.5dB. +

+ +

+For testing, we apply a pink noise signal, which displays as a straight line +in the analyser. 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. +

+

+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: +

+ +

+Depending on your material and on how much you need to manipulate the width, +the comb filter may be acceptable. Then again, it may not be. Listen +carefully for artefacts if you manipulate unknown stereo signals - many +orchestra sample libraries for example do contain time-delay components. +

+