diff --git a/noptica.py b/noptica.py
index a3fe8fb..5587a00 100644
--- a/noptica.py
+++ b/noptica.py
@@ -195,7 +195,7 @@ class LinearPhaseFilter:
     def __init__(self, numtaps, *args, **kwargs):
         self.numtaps = numtaps
         self.coef = signal.firwin(numtaps, *args, **kwargs)
-        self.state = np.zeros(self.numtaps - 1)
+        self.state = np.zeros(self.numtaps - 1, dtype="complex64")
 
     def input(self, block):
         output, self.state = signal.lfilter(self.coef, [1.0], block, zi=self.state)
@@ -210,8 +210,8 @@ class Delay:
     def __init__(self, block_size, delay_amount):
         self.block_size = block_size
         self.delay_amount = delay_amount
-        self.output = np.zeros(block_size)
-        self.next = np.zeros(delay_amount)
+        self.output = np.zeros(block_size, dtype="complex64")
+        self.next = np.zeros(delay_amount, dtype="complex64")
 
     def input(self, block):
         assert(len(block) == self.block_size)