diff --git a/app/controllers/tracks_controller.rb b/app/controllers/tracks_controller.rb
index a54184b3..945ee087 100644
--- a/app/controllers/tracks_controller.rb
+++ b/app/controllers/tracks_controller.rb
@@ -116,6 +116,10 @@ def audio_with_stream(stream, mimetype, total_size)
     response.content_type = mimetype
     response.headers['accept-ranges'] = 'bytes'
     response.headers['content-length'] = (last_byte - first_byte + 1).to_s
+    # Unfortunately, if we don't commit the headers, ActionController::Live will
+    # delete the "content-length" header set above. No other headers need to be
+    # set, so we just freeze them here.
+    response.commit!
 
     to_skip = first_byte
     while to_skip.positive?