I have a client with a Avaya IP office. Their voice messages are being sent to them through email from the IP office system as wave file attachments whee a message if received.
One employee showed me the file plays perfectly when received in outlook on Win7. When it is received on his iPhone 5, it sounds very scratchy and is distorted. This happens with his earbuds and the phone's speaker activated.
I had him forward that email to my (iPhone 5) and it sounded the same when I played the attachment.
The distortion is intermitent but all attachments are wave files.