$re = '/ spk:(rt722) spk:(rt1320)/';
$str = 'HDA:8086281d,80860101,00100000 cfg-amp:2 hs:rt722 spk:rt722 spk:rt1320';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php