Php convert binary to file

I'm using a service that gives you a wav file. this service gives me base64 binary code as a result. I want to convert it to a wav file.

I've been googling for it and couldn't find anything. here is my code :

    $wsdl=' < url > ';//url to WSDL
    $client = new SoapClient[$wsdl];
    $param=array[
        'userName'=>' < my username> ',
        'password'=>' < my password > ',
        'messageId'=>1063716
    ]; // parameters needed to download the file 
    try{
       $res=$client->DownloadMessage[$param]    ;
       $base64Binary = $res->DownloadMessageResult;
       echo $base64Binary;
       }catch[Exception $e]{
           echo '
' ;
           var_dump[$e->getMessage[]];
           echo '
' ;
       }

and the result of the echo is this:

RIFF&WAVEfmt @€>dataÞ%¯ÿ@HrÿvÿÿâÿÂÿ7Æÿ‚ÿžÿ€ÿÎÿÌÿQQÝV…‚© K 6[Iv7%ýÿñÿÃÿªÿÐÿ¦ÿÜÿWÿKÿ®ÿ¯ÿÝÿ”ÿ•ÿwÿ¹ÿ¶\JŸœñ{KH66þÿõÿõÿäÿªÿDÚÿ÷ÿªÿìÿÒÿNóÿØÿÈÿÝÿÄÿÞÿžÿ'Úÿ¾ÿÒÿYÿqÿ…ÿÌÿ×ÿÃÿµÿ¸ÿÉÿÏÿñÿŸ‰¿uÚÿ$x;^UÁÿ¾ÿÅÿ|ÿ­ÿ¤ÿøÿüÿÿ™ÿèÿªÿmÿ…ÿAÿ™ÿŒÿ0ÿÿˆÿB•ùÿ·ÿ†™ðjÖ=1µê}*|!\¾µÇÿ¥ÿØÿÿ[¸ÿÁÿŸÿ÷ÿêÿœÿõÿsÿ¤Ùÿ#ôÿƒÿ[Ÿâÿ›ÿÝÿ;§ÿ,ÕÿMK¾ÿü¢û—ûžû#üŠüÖüý%ýuý¶ý;þµþ0ÿaÿÁÿ±ÿ3ùwÙuç^ ßÄ IH®îÿRýû¤÷cöÛõ¤õRöØöD÷Fö¡õÿô!õ  öG÷YøÅøþùðúÏû±ý°ÿÓIÓÈ   ž‘ £=JÇt@"þÿûÿúÿøÿ÷ÿöÿöÿôÿôÿöÿùÿ7k°7÷ÇÅÝ•¥›Ð‹Ü”oó3‘èT²ÿøþ}þ¸ý'ý üzügüLübügüœü«üýCý¦ýõýUþ„þ½þïþ5ÿkÿýÿ3à»dl«œ¾`Å3vþýû¿ùrøo÷’õ-ô¡ó˜ó3ôÛôfõÖõªö¯÷“ø²ùû²ü¦þ¯TªÚ¸ƒ¥—¿]ÂzN/ýÿüÿúÿùÿøÿ÷ÿöÿõÿ÷ÿýÿ@}ÍDâråDmqb/Þ~$Êc©T#úÿ°ÿ™ÿ¡ÿ“ÿ£ÿ¤ÿvÿfÿ^ÿCÿ?ÿ;ÿ%ÿÿÿõþýþÿ+ÿ9ÿcÿ|ÿÜÿøÖäÏ~U o·ö…·3áÿÿ«ýˆü©û®ú’ù×ørø4øJøUø…øÌø:ùÁùJúûÆû—ü¹ýíþâÿßÝ…ÝØvñsº~T6$ÿÿÿÿþÿþÿÿÿþÿýÿýÿüÿþÿ#:PaixŒ‡yreSKH>22*   ýÿõÿíÿæÿÜÿÒÿÎÿÕÿÜÿ×ÿÙÿÞÿåÿêÿöÿ÷ÿøÿ6m@ÏûeÜ.„w    íuõ¿o   ÑŠ*ñÿÚÿ§ÿrÿ[ÿ/ÿ ÿÿãþ¤þ†þ€þwþ€þªþÕþÿNÿÿ·ÿ×ÿ6a€ï9ŸÕ³¯ÆT]¥¯ÿ„ÿQÿÿòþwþþþ[þQþ•þØþõþ¬þˆþšþNþþñýoý]ýõýrþÓþ!ÿ*ÿ"ÿ/ÿ4ÿBÿKÿÿUÿPÿKÿFÿ:ÿMÿ–ÿÏÿÕÿüÿI…™™~aKH3ïÿ¦ÿ˜ÿ¨ÿšÿ‚ÿdÿOÿDÿIÿ=ÿ2ÿDÿ]ÿmÿyÿÿ{ÿ”ÿ½ÿÌÿÀÿ½ÿ¾ÿÐÿñÿûÿáÿ¾ÿ©ÿ¤ÿ©ÿ¢ÿ˜ÿžÿºÿÊÿËÿÑÿàÿúÿ#&%+I]f{–«¦”~zuaG5/-÷ÿíÿæÿÔÿ¾ÿ­ÿ›ÿÿŠÿ–ÿ¤ÿ°ÿ®ÿ«ÿ®ÿ²ÿÂÿÃÿÃÿÅÿµÿ¬ÿ¡ÿŒÿÿ›ÿ¡ÿ›ÿ’ÿÿžÿ°ÿ¶ÿÇÿÒÿÜÿêÿýÿüÿ!" ÷ÿ÷ÿýÿóÿëÿîÿèÿßÿÞÿÌÿÀÿÇÿÀÿ½ÿÊÿÕÿÕÿØÿÕÿÕÿÕÿØÿãÿãÿáÿÝÿæÿ÷ÿ   [28