diff --git a/lib/render.js b/lib/render.js
index aa1df1b..36f5a5f 100644
--- a/lib/render.js
+++ b/lib/render.js
@@ -34,7 +34,7 @@ function getPcmData (filename, options, sampleCallback, endCallback) {
   }
 
   if (!fs.existsSync(filename)) {
-    throw `File doesn't exist: ${filename}`
+    throw new Error(`File doesn't exist: ${filename}`)
   }
 
   var ffmpeg = spawn('ffmpeg', ['-i', filename, '-f', 's16le', '-ac', channels,