diff --git a/test/assert_delta.c b/test/assert_delta.c
index 6dad6992..6ef11fea 100644
--- a/test/assert_delta.c
+++ b/test/assert_delta.c
@@ -34,7 +34,7 @@ int main(int argc, char** argv) {
   while ((totalRead=sf_readf_float(sf,buf,BUF_SIZE))!=0) {
     for (int i=0; i<totalRead*si.channels; i++) {
       if (buf[i]!=0.0f) {
-        printf("%ld\n",seekPos+(i/si.channels));
+        //printf("%ld\n",seekPos+(i/si.channels));
         sf_close(sf);
         free(buf);
         return 1;
diff --git a/test/furnace-test.sh b/test/furnace-test.sh
index bb0ec375..c6e0f8f4 100755
--- a/test/furnace-test.sh
+++ b/test/furnace-test.sh
@@ -23,7 +23,7 @@ fi
 echo "furnace test suite begin..."
 echo "--- STEP 1: render test files"
 mkdir -p "test/result/$testDir" || exit 1
-ls "test/songs/" | parallel --verbose -j4 ./build/furnace -output "test/result/$testDir/{0}.wav" "test/songs/{0}"
+ls "test/songs/" | parallel --verbose -j8 ./build/furnace -output "test/result/$testDir/{0}.wav" "test/songs/{0}"
 echo "--- STEP 2: calculate deltas"
 if [ -z $lastTest ]; then
   echo "skipping since this apparently is your first run."