public function getRandomNoiseFile()
    {
        $return = false;

        if ( ($dh = opendir($this->audio_noise_path)) !== false ) {
            $list = array();

            while ( ($file = readdir($dh)) !== false ) {
                if ($file == '.' || $file == '..') continue;
                if (strtolower(substr($file, -4)) != '.wav') continue;

                $list[] = $file;
            }

            closedir($dh);

            if (sizeof($list) > 0) {
                $file   = $list[array_rand($list, 1)];
                $return = $this->audio_noise_path . DIRECTORY_SEPARATOR . $file;

                if (!is_readable($return)) $return = false;
            }
        }

        return $return;
    }