diff --git a/.travis.yml b/.travis.yml
index 6753d573..83722930 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -27,7 +27,7 @@ jobs:
     script: .travis/script_test.sh
 
   - name: "Linux arm64 tests"
-    arch: amd64
+    arch: arm64
     addons:
       apt:
         packages:
diff --git a/src/sfizz/Curve.cpp b/src/sfizz/Curve.cpp
index b29fbf15..44aa3c24 100644
--- a/src/sfizz/Curve.cpp
+++ b/src/sfizz/Curve.cpp
@@ -79,20 +79,24 @@ Curve Curve::buildPredefinedCurve(int index)
         break;
     case 4:
         for (unsigned i = 0; i < NumValues; ++i) {
-            double x = i * (1.0 / (NumValues - 1));
+            double x = i / static_cast<double>(NumValues - 1);
             curve._points[i] = x * x;
         }
         break;
     case 5:
-        for (unsigned i = 0; i < NumValues; ++i) {
-            double x = i * (1.0 / (NumValues - 1));
-            curve._points[i] = std::pow(x, 0.5);
+        curve._points[0] = 0.0;
+        curve._points[NumValues - 1] = 1.0;
+        for (unsigned i = 1; i < NumValues - 1; ++i) {
+            double x = i / static_cast<double>(NumValues - 1);
+            curve._points[i] = std::sqrt(x);
         }
         break;
     case 6:
-        for (unsigned i = 0; i < NumValues; ++i) {
-            double x = i * (1.0 / (NumValues - 1));
-            curve._points[i] = std::pow(1.0 - x, 0.5);
+        curve._points[0] = 1.0;
+        curve._points[NumValues - 1] = 0.0;
+        for (unsigned i = 1; i < NumValues - 1; ++i) {
+            double x = i / static_cast<double>(NumValues - 1);
+            curve._points[i] = std::sqrt(1.0 - x);
         }
         break;
     }