diff --git a/crates/effects/src/channel3d.rs b/crates/effects/src/channel3d.rs
index 7884e808..9eb8f4dd 100644
--- a/crates/effects/src/channel3d.rs
+++ b/crates/effects/src/channel3d.rs
@@ -37,16 +37,24 @@ fn index_map(b: &Buf, a: &AuxChannels) -> Vec