Ableton Live 8 crackling noise

Hi there,br
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I’m using Ableton Live 8 Beta and I’m hearing this odd crackling distorted noise on my exported song (that is once I’ve finished editing it on Ableton and have clicked “export audio” and have opened it through iTunes). When the song is played through Ableton there is NO crackling/distortion. I have already made sure the master volume isn’t peaking, as in turning red.br
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Please help asap, there’s a guy at a record label that wants my song but i need to sort this out first.br
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Many thanks,br
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William N-C