diff --git a/config.json b/config.json
index 5cf02505..23868a33 100644
--- a/config.json
+++ b/config.json
@@ -29,7 +29,7 @@
         "num_mels": 80,         // size of the mel spec frame.
         "mel_fmin": 0.0,        // minimum freq level for mel-spec. ~50 for male and ~95 for female voices. Tune for dataset!!
         "mel_fmax": 8000.0,     // maximum freq level for mel-spec. Tune for dataset!!
-        "spec_gain": 20,
+        "spec_gain": 20.0,
 
         // Normalization parameters
         "signal_norm": true,    // normalize spec values. Mean-Var normalization if 'stats_path' is defined otherwise range normalization defined by the other params.