I've never tried this, but there is a little program SoX at http://sox.sourceforge.net/ that you can use to concat sound fils .... you fetch first audio then write to a file $file1 = "/tmp/audio1.wma"; // maybe is better generate a random name for the file $descriptor = fopen ($file1, "w"); fwrite($descriptor,$audio); fclose($descriptor); .... you fetch second audio then write to another file $file2 = "/tmp/audio2.wma"; $descriptor2 = fopen ($file2, "w"); fwrite($descriptor2,$audio); fclose($descriptor2); .... then you concat audio files with sox $finalfile = "/tmp/final.wma"; $cmd = "sox $file1 $file2 $finalfile"; shell_exec($cmd); ... erase temporary files unlink($file1); unlink($file2); ... the last task is to open final.wma, read and return to client $descriptor3 = fopen($finalfile,"r"); $audio = fread ($descriptor3, filesize ($finalfile)); fclose($descriptor3) echo $audio A better solution would be put $finalfile in a directory under your document root in webserver and redirect header to it.