diff --git a/test/acm_random.h b/test/acm_random.h
index 8c748b8..1025e84 100644
--- a/test/acm_random.h
+++ b/test/acm_random.h
@@ -39,10 +39,15 @@
 
   int16_t Rand16Signed() { return static_cast<int16_t>(Rand16()); }
 
-  int16_t Rand15Signed() {
+  int16_t Rand15() {
     const uint32_t value =
         random_.Generate(testing::internal::Random::kMaxRange);
-    return (value >> 17) & 0xffff;
+    return (value >> 16) & 0x7fff;
+  }
+
+  int16_t Rand15Signed() {
+    // Use 15 bits: values between 16383 (0x3FFF) and -16384 (0xC000).
+    return static_cast<int16_t>(Rand15()) - (1 << 14);
   }
 
   uint16_t Rand12() {
diff --git a/test/cfl_test.cc b/test/cfl_test.cc
index 98cc9ab..97533da 100644
--- a/test/cfl_test.cc
+++ b/test/cfl_test.cc
@@ -192,7 +192,7 @@
 
 TEST_P(CFLSubAvgTest, SubAvgTest) {
   for (int it = 0; it < NUM_ITERATIONS; it++) {
-    randData(&ACMRandom::Rand15Signed);
+    randData(&ACMRandom::Rand15);
     sub_avg((uint16_t *)data, data);
     sub_avg_ref((uint16_t *)data_ref, data_ref);
     assert_eq<int16_t>(data, data_ref, width, height);
@@ -202,7 +202,7 @@
 TEST_P(CFLSubAvgTest, DISABLED_SubAvgSpeedTest) {
   aom_usec_timer ref_timer;
   aom_usec_timer timer;
-  randData(&ACMRandom::Rand15Signed);
+  randData(&ACMRandom::Rand15);
   aom_usec_timer_start(&ref_timer);
   for (int k = 0; k < NUM_ITERATIONS_SPEED; k++) {
     sub_avg_ref((uint16_t *)data_ref, data_ref);
diff --git a/test/encodetxb_test.cc b/test/encodetxb_test.cc
index ee09ea6..c1b6709 100644
--- a/test/encodetxb_test.cc
+++ b/test/encodetxb_test.cc
@@ -229,7 +229,7 @@
 
   ACMRandom rnd(ACMRandom::DeterministicSeed());
   for (int i = 0; i < width * height; i++) {
-    coeff[i] = rnd.Rand15Signed() + rnd.Rand15Signed();
+    coeff[i] = rnd.Rand16Signed();
   }
   for (int i = 0; i < TX_PAD_2D; i++) {
     levels_buf[0][i] = rnd.Rand8();