diff --git a/src/main_osp.cc b/src/main_osp.cc
index d4ac1ea..a0b5ac8 100644
--- a/src/main_osp.cc
+++ b/src/main_osp.cc
@@ -100,7 +100,36 @@ namespace Heck {
         }
     }
 
-    void midi_realtime_handler(ld::MidiEvent& msg)
+    void audio_callback_new(ld::AudioHandle::InputBuffer in, ld::AudioHandle::OutputBuffer out, size_t size)
+    {
+        // Output 1
+        {
+            float sig_out{};
+            float sig_osp{};
+            float sig_ext_in_1{};
+            float sig_ext_in_2{};
+            for (size_t i = 0; i < size; i++) {
+                for (int i = 0; i < Constants::TRACK_COUNT; i++) {
+                    sig_osp += tracks[i].nextsample();
+                }
+                sig_osp /= Constants::TRACK_COUNT;
+                sig_ext_in_1 = in[0][i];
+                sig_ext_in_2 = in[1][i];
+                out[0][i] = sig_osp + sig_ext_in_1 + sig_ext_in_2 / 3.;
+                out[1][i] = out[0][i];
+            }
+        }
+
+        // Output 2
+        if constexpr (false) {
+            for (size_t i = 0; i < size; i++) {
+                out[1][i] = in[1][i];
+            }
+        }
+    }
+
+
+    void midi_realtime_handler(const ld::MidiEvent &msg)
     {
         event_log.PushBack(msg);
         switch (msg.srt_type) {