diff --git a/src/.DS_Store b/src/.DS_Store
index 5008ddf..14624d2 100644
Binary files a/src/.DS_Store and b/src/.DS_Store differ
diff --git a/src/Main_test.m b/src/Main_test.m
index b6de4b4..31f53eb 100644
--- a/src/Main_test.m
+++ b/src/Main_test.m
@@ -32,5 +32,4 @@ release = 0.1;
 x = DarellAmplitudeEnvelope(x, fs, attack,decay,sustain,release); %output new sound in time domain
 %play over 5 counts, should only hear 200hz
 playtime = 5;
-play_continuous(x, fs, playtime)
-
+play_continuous(x, fs, playtime)
\ No newline at end of file
diff --git a/src/amplify.m b/src/amplify.m
new file mode 100644
index 0000000..153767b
--- /dev/null
+++ b/src/amplify.m
@@ -0,0 +1,8 @@
+function output = amplify(input, multiplier)
+    %input: a 1D array representing the sound signal in the time domain
+    %multiplier: a scalar that multiplier all values in the input array to
+    %            amplify or decrease the volume.
+    %Returns: input signal scaled by the multiplier in the time domain.
+    %Author: Conner Hsu
+    output = input*multiplier;
+end
\ No newline at end of file
diff --git a/src/reverse.m b/src/reverse.m
new file mode 100644
index 0000000..586c606
--- /dev/null
+++ b/src/reverse.m
@@ -0,0 +1,6 @@
+function output = reverse(input)
+    %input: a 1D array representing the sound signal in the time domain
+    %returns: the input signal with its elements in reverse order.
+    %By Conner Hsu
+    output = flip(input);
+end
\ No newline at end of file