I suppose concatenation could be used here instead, in case that's preferred over escaping double-quotes.
` $command = $lame_url . ' -V5 --vbr-new "' . $file . '" "' . $outfile . '"'; `
Obviously, we can't wrapper the string in single-quotes or the embedded variables won't get interpreted correctly. [[Reference](http://www.php.net/manual/en/language.types.string.php#language.types.string.syntax.single "PHP: Strings - Single quoted")]