diff --git a/enhancer/models/complexnn/rnn.py b/enhancer/models/complexnn/rnn.py
index 7d19425..847030b 100644
--- a/enhancer/models/complexnn/rnn.py
+++ b/enhancer/models/complexnn/rnn.py
@@ -42,6 +42,8 @@ class ComplexLSTM(nn.Module):
             self.imag_linear = nn.Linear(
                 self.hidden_size * bidirectional, self.projection_size
             )
+        else:
+            self.projection_size = None
 
     def forward(self, input):