diff --git a/audio_engine/src/process_handler.rs b/audio_engine/src/process_handler.rs
index 14b33b0..d45ac1e 100644
--- a/audio_engine/src/process_handler.rs
+++ b/audio_engine/src/process_handler.rs
@@ -205,6 +205,13 @@ impl<F: ChunkFactory, const COLS: usize, const ROWS: usize> ProcessHandler<F, CO
         self.track_matrix
             .process(ps, &mut self.ports, &timing, &controllers)?;
 
+        let input_buffer = self.ports.audio_in.as_slice(ps);
+        let output_buffer = self.ports.audio_out.as_mut_slice(ps);
+
+        for i in 0..output_buffer.len() {
+            output_buffer[i] = output_buffer[i] + (input_buffer[i] * self.last_volume_setting);
+        }
+
         Ok(())
     }
 }