diff --git a/tests/compile-tests/Make.lang b/tests/compile-tests/Make.lang
index 987b68803a..f1ea9be189 100644
--- a/tests/compile-tests/Make.lang
+++ b/tests/compile-tests/Make.lang
@@ -15,6 +15,7 @@ SAMPLESROOT := ../..
 REGRESSION := ..
 FAUSTLIBS1 ?= ../../libraries
 FAUSTLIBS2 ?= ../../libraries/old
+FAUSTLIBS3 ?= ../../libraries/dx7
 
 FAUSTOPTIONS ?= 
 outdir ?= cpp
@@ -96,8 +97,8 @@ $(version)/$(outdir):
 # generic rule rule for $(lang) output
 $(version)/$(outdir)/%.$(ext): $(SAMPLESROOT)/%.dsp
 	@[ -d $(@D) ] || mkdir -p $(@D)
-	$(FAUST) -lang $(lang) -I $(FAUSTLIBS1) -I $(FAUSTLIBS2) $(FAUSTOPTIONS) $<  -o $@ 
+	$(FAUST) -lang $(lang) -I $(FAUSTLIBS1) -I $(FAUSTLIBS2) -I $(FAUSTLIBS3) $(FAUSTOPTIONS) $<  -o $@ 
 	
 $(version)/$(outdir)/%.$(ext): $(REGRESSION)/%.dsp
 	@[ -d $(@D) ] || mkdir -p $(@D)
-	$(FAUST) -lang $(lang) -I $(FAUSTLIBS1) -I $(FAUSTLIBS2) $(FAUSTOPTIONS) $<  -o $@ 
+	$(FAUST) -lang $(lang) -I $(FAUSTLIBS1) -I $(FAUSTLIBS2) -I $(FAUSTLIBS3) $(FAUSTOPTIONS) $<  -o $@ 
diff --git a/tests/compile-tests/Makefile b/tests/compile-tests/Makefile
index 4e42033821..87b8b3977c 100644
--- a/tests/compile-tests/Makefile
+++ b/tests/compile-tests/Makefile
@@ -19,6 +19,7 @@ SAMPLESROOT := ../..
 REGRESSION := ..
 FAUSTLIBS1 ?= ../../libraries
 FAUSTLIBS2 ?= ../../libraries/old
+FAUSTLIBS3 ?= ../../libraries/dx7
 FAUSTINC  ?= ../../architecture/faust
 
 # Lists of DSPs used by the JSON targets (examples + codegen-tests, minus exclusions)
@@ -52,7 +53,7 @@ bench_value() { \
   : Run faustbench and echo the parsed MBytes/sec value.; \
   file="$$1"; \
   tmp=$$(mktemp); \
-  if $(FAUSTBENCH) $(BENCH_OPTIONS) -I $(FAUSTLIBS1) -I $(FAUSTLIBS2) "$$file" > "$$tmp" 2>&1; then \
+	if $(FAUSTBENCH) $(BENCH_OPTIONS) -I $(FAUSTLIBS1) -I $(FAUSTLIBS2) -I $(FAUSTLIBS3) "$$file" > "$$tmp" 2>&1; then \
     line="$$(grep -m1 'MBytes/sec' "$$tmp" || true)"; \
     if [ -n "$$line" ]; then \
       val="$$(printf '%s\n' "$$line" | sed -nE 's/.*: ([0-9.]+) MBytes\/sec.*/\1/p')"; \
@@ -320,7 +321,7 @@ for file in $(DSP_EXAMPLES) $(DSP_REGRESSION); do \
 	esac; \
 	dest=$$outdir/$$(dirname -- "$$rel"); \
 	mkdir -p "$$dest"; \
-	$(FAUST) -lang cpp -I $(FAUSTLIBS1) -I $(FAUSTLIBS2) -json "$$file" -O "$$dest" > /dev/null; \
+	$(FAUST) -lang cpp -I $(FAUSTLIBS1) -I $(FAUSTLIBS2) -I $(FAUSTLIBS3) -json "$$file" -O "$$dest" > /dev/null; \
 done
 endef