Hi all, I've found a couple of threads relating to this problem but I can't for the life of me get it to work. The following command line works fine: sox original.wav -c 1 -r 8000 converted.wav I can't get it to work with libsox. I've made a tiny modification to example3.c that should do the same but no matter what I try I always end up with a file that is exactly half the length of the one I get from sox (or some crazy audio). If I leave the output as stereo I get the full length audio but sadly stereo is no use to me. The 2 threads I've found are [Sox-devel] 'Effects going crazy' - 2012-05-07 and [SoX] 'Channels/remix does not function as documented' - 2011-11-12 Nothing suggested in either seems to work for me. Could someone take a look at the attached code (it's very simple) to see if they can see what I'm doing wrong please? It's driving me crazy! I'm at the point of giving up and just spawning the sox executable from my code but that would make me cry. The following is the format of my test input file but it needs to work for any wav file: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 24000 Hz Desired output will always be in the following format regardless of the input format: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, mono 8000 Hz Apologies if this is more appropriate for sox-users. If so, just let me know and I'll post there. Cheers Stephen Paterson Developer | SYNETY www.synety.com ddi: 01134 166029 main: 0330 335 0000 SMARTER COMMUNICATIONS Confidentiality: This e-mail transmission, including any attachments, is intended only for the named recipient(s) and may contain information that is privileged, confidential and/or exempt from disclosure under applicable law. If you have received this transmission in error, or are not the named recipient(s), please notify the sender immediately by return e-mail and permanently delete this transmission, including any attachments. Security: This e-mail and any attachments are believed to be free from any virus but it is the responsibility of the recipient to ensure this is so. E-mail is not a 100% secure communications medium. We recommend you observe this when e-mailing us.