diff --git a/Makefile b/Makefile
index 738a33c..9110593 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,5 @@
-WORKING_DIR:=$(shell pwd)
+mkfile_path := $(abspath $(lastword $(MAKEFILE_LIST)))
+WORKING_DIR := $(patsubst %/,%,$(dir $(mkfile_path)))
 BOOKNAME=kommersbuch
 SRC_DIR=src
 BUILD_DIR=build
@@ -59,7 +60,7 @@ ${BUILD_MIDI_DIR}/%.midi: ${TMP_MIDI_DIR}/%-1.midi
 	cp $< $@
 
 ${TMP_MIDI_DIR}/%-1.midi: ${SONG_DIR}/%.ly
-	lilypond --output=${TMP_MIDI_DIR} $<
+	lilypond --output=${TMP_MIDI_DIR} ${WORKING_DIR}/$<
 
 ${BUILD_OPUS_DIR}/%.opus: ${BUILD_MIDI_DIR}/%.midi
 	timidity $< -Ow -o - | opusenc - $@