Update preprocessor_config.json

preprocessor_config.json

@@ -12,5 +12,9 @@
   "vocab_size_special": 4,
   "vocab_size_note": 128,
   "vocab_size_velocity": 2,
-  "vocab_size_time": 100
+  "vocab_size_time": 100,
+  "n_fft":4096,
+  "hop_length":1024,
+  "f_min":10.0,
+  "n_mels":512
 }