diff --git a/kokoro/istftnet.py b/kokoro/istftnet.py
index e61e510..5e4143e 100644
--- a/kokoro/istftnet.py
+++ b/kokoro/istftnet.py
@@ -23,7 +23,8 @@ def get_padding(kernel_size, dilation=1):
 class AdaIN1d(nn.Module):
     def __init__(self, style_dim, num_features):
         super().__init__()
-        self.norm = nn.InstanceNorm1d(num_features, affine=False)
+        # affine should be False, however there's a bug in the old torch.onnx.export (not newer dynamo) that causes the channel dimension to be lost if affine=False. When affine is true, there's additional learnably parameters. This shouldn't really matter setting it to True, since we're in inference mode
+        self.norm = nn.InstanceNorm1d(num_features, affine=True)
         self.fc = nn.Linear(style_dim, num_features*2)
 
     def forward(self, x, s):