diff --git a/ardour5.spec b/ardour5.spec
index c8d67c9..07a5c27 100644
--- a/ardour5.spec
+++ b/ardour5.spec
@@ -19,6 +19,9 @@
 %global _verbose %{nil}
 %endif
 
+# whether to use system libraries
+%bcond_without system_libs
+
 %global backends jack,alsa,dummy
 %global default_backend jack
 
@@ -155,6 +158,13 @@ This package provides the %{2} %{1} backend for Ardour.\
 %prep
 %autosetup -p1 -n Ardour-%{version}
 
+%if %{with system_libs}
+# remove bundled library sources
+for i in libltc qm-dsp; do
+    find "libs/$i" \( -name \*.\[ch\] -o -name \*.cc -o -name \*.\[ch\]pp \) -delete
+done
+%endif
+
 # use versionized name for all man pages
 for fromfile in ardour.1 ardour.1.??; do
     tofile="%{name}${fromfile#ardour}"
@@ -192,7 +202,9 @@ export LC_ALL=en_US.UTF-8
 %else
     --arch="%optflags" \
 %endif
+%if %{with system_libs}
     --use-external-libs \
+%endif
 %if %{with cxx11}
     --cxx11 \
 %endif
@@ -320,6 +332,7 @@ fi
 %changelog
 * Tue Aug 16 2016 Nils Philippsen <nils@tiptoe.de>
 - unbundle qm-dsp
+- remove sources of unbundled libraries in %%prep
 
 * Sun Aug 14 2016 Nils Philippsen <nils@tiptoe.de> - 5.0.0-0.6
 - update LICENSING