Doc -- Clarify instructions on autobeam settings

Multiple \time calls can revert custom autobeam settings.  Clarify
in the documentation.

diff --git a/Documentation/notation/rhythms.itely b/Documentation/notation/rhythms.itely
index f0d518d99d1720d3de4b9ef9c82c12e95aaadae8..40fc4ec61091c45c040027ace5b0a9321f986ee9 100644 (file)
--- a/Documentation/notation/rhythms.itely
+++ b/Documentation/notation/rhythms.itely
@@ -2085,12 +2085,13 @@ context to the default behavior.
 \repeat unfold 6 { a8 }
 @end lilypond
 
-These default automatic beaming settings for a time signature
+
+The default automatic beaming settings for a time signature
 are determined in @file{scm/time-signature-settings.scm}.
-The automatic beaming settings for a time signature can be changed
-as described in @ref{Time signature}.
+Changing the default automatic beaming settings
+for a time signature is described in @ref{Time signature}.
 
-Most automatic beaming settings for a time signature contain an
+Many automatic beaming settings for a time signature contain an
 entry for @code{beamExceptions}.  For example, 4/4 time tries to
 beam the measure in two if there are only eighth notes.  The
 @code{beamExceptions} rule can override the @code{beatStructure} setting
@@ -2202,6 +2203,51 @@ automatic beam is still accepting notes, it is not typeset.
 The workaround for these problems is to manually beam the last
 beam in the voice or score.
 
+By default, the @code{Timing} translator is aliased to the
+@code{Score} context.  This means that setting the time signature
+in one staff will affect the beaming of the other staves as well.
+Thus, a time signature setting in a later staff will reset custom
+beaming that was set in an earlier staff.
+One way to avoid this problem is to set the time signature
+in only one staff.
+
+@lilypond[quote,verbatim,relative=2]
+<<
+  \new Staff {
+    \time 3/4
+    \set Timing.baseMoment = #(ly:make-moment 1 8)
+    \set Timing.beatStructure = #'(1 5)
+    \repeat unfold 6 { a8 }
+  }
+  \new Staff {
+    \repeat unfold 6 { a8 }
+  }
+>>
+@end lilypond
+
+The default beam settings for the time signature can also be
+changed, so that set the desired beaming will always be used
+Changes in automatic beaming settings
+for a time signature are described in @ref{Time signature}.
+
+@lilypond[quote,verbatim,relative=2]
+<<
+  \new Staff {
+    \overrideTimeSignatureSettings
+      #'(3 . 4)         % timeSignatureFraction
+      #'(1 . 8)         % baseMomentFraction
+      #'(1 5)           % beatStructure
+      #'()             % beamExceptions
+    \time 3/4
+    \repeat unfold 6 { a8 }
+  }
+  \new Staff {
+    \time 3/4
+    \repeat unfold 6 { a8 }
+  }
+>>
+@end lilypond
+
 @node Manual beams
 @unnumberedsubsubsec Manual beams