diff --git a/interface/CMakeLists.txt b/interface/CMakeLists.txt
index fd31c0a0d8..c2410660aa 100644
--- a/interface/CMakeLists.txt
+++ b/interface/CMakeLists.txt
@@ -41,7 +41,7 @@ ExternalProject_Add(
     PREFIX ${PORTAUDIO_PROJ_DIR}
     BINARY_DIR ${PORTAUDIO_PROJ_DIR}/src/portaudio
     URL ${PORTAUDIO_DIR}/pa_snapshot_020813.tgz
-    CONFIGURE_COMMAND <SOURCE_DIR>/configure --prefix ${CMAKE_CURRENT_SOURCE_DIR}/${PORTAUDIO_PROJ_DIR}
+    CONFIGURE_COMMAND <SOURCE_DIR>/configure --prefix ${PROJECT_SOURCE_PATH}/${PORTAUDIO_PROJ_DIR}
     BUILD_COMMAND make
 )