Laravel - this->validate and Validator::make() do the difference for upload file

When i upload file Validator::make() will catch if a file too big and $this->validate is not.

My example:

$this->validate($request, [
    'my_audio' => 'mimes:wav,mp3', //only allow this type extension file.
]);
// not catch

and

$validator = Validator::make($request->all(), [
    'my_audio' => 'mimes:wav,mp3',
]);
if ($validator->fails()) {
   // catched
}

How to fix that if i using $this->validate thank

via Chebli Mohamed