diff --git a/src/stream.rs b/src/stream.rs
index 7fe044e..ddb30d0 100644
--- a/src/stream.rs
+++ b/src/stream.rs
@@ -160,7 +160,7 @@ fn main(streamer: Arc<Mutex<Streamer>>) -> anyhow::Result<()> {
                     .unwrap()
                     .as_secs_f64();
                 let dt = now - start;
-                let cutoff = mid + f64::sin(dt / hz) * 0.5 * range;
+                let cutoff = mid + f64::sin(dt * hz) * 0.5 * range;
                 // swap the bytes, we are using LE, not BE, 16 bit grayscale
                 // possibly limitation of current v4l2loopback or v4l rust wrapper or libv4l2
                 for i in 0..FRAME_LEN / 2 {