From 25ea2abdb17253dae98fca5c904e3e4399b35ab7 Mon Sep 17 00:00:00 2001
From: =?utf8?q?J=C3=B6rn=20Nettingsmeier?=
@@ -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
+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. +
+ -- 2.37.2