diff --git a/lib/tasks/tts-task.js b/lib/tasks/tts-task.js
index e942fdb7..0cfd4a0c 100644
--- a/lib/tasks/tts-task.js
+++ b/lib/tasks/tts-task.js
@@ -152,7 +152,6 @@ class TtsTask extends Task {
     } else if (vendor === 'deepgram') {
       this.model = voice;
     }
-    this.model_id = credentials.model_id;
 
     /* allow for microsoft custom region voice and api_key to be specified as an override */
     if (vendor === 'microsoft' && this.options.deploymentId) {
@@ -193,8 +192,12 @@ class TtsTask extends Task {
           };
         }
       }
+    } else if (vendor === 'cartesia') {
+      credentials.model_id = this.options.model_id || credentials.model_id;
     }
 
+    this.model_id = credentials.model_id;
+
     /**
      * note on cache_speech_handles.  This was found to be risky.
      * It can cause a crash in the following sequence on a single call: