I take it that there is no problem with headerless output.
I found an e-mail relating to what I was investigating then, it was to do with scaling.
Maybe it's also relevant?

http://csound.1045644.n5.nabble.com/scaling-of-float-soundfiles-tt1136362.html#none

----- Original Message -----
From: Tito Latini <tito.01beta@gmail.com>
Date: Thursday, September 13, 2012 9:42 pm
Subject: Re: [Csnd] default output format, stdout and pipe
To: csound@lists.bath.ac.uk

> Some details: with wav, aiff, etc, libsndfile uses `fstat' to see
> if the file is a pipe or a socket. In this case, it returns NULL.
> There are not problems with redirections
>
> csound -o stdout test.csd > test.wav
>
> because `fstat' knows that the standard output is redirected.
>
>
> Send bugs reports to the Sourceforge bug tracker
> https://sourceforge.net/tracker/?group_id=81968&atid=564599
> Discussions of bugs and features can be posted here
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> "unsubscribe csound"
>

Dr Victor Lazzarini, Senior Lecturer, Dept. of Music,
National University of Ireland, Maynooth