Audio problem - ATC repeats words

I have had a intermittent audio problem from the start with FSX. Sometimes, ATC repeats words. For example, it should say "United 777 climb and maintain, 15000. But what I hear is "United 777, climb and maintain, climb and maintain, 15000".My audio card is a Creative Sound Blaster, Audigy 2 ZS. I have downloaded latest drivers, but no help. Matt Fox, had published some information on reinstalling the Microsoft ADPCM Codec. I have tried that twice - no help. I wonder if this could be a (known) problem with my sound card? I have also made adjustments to acceleration after running DXDIAG -Audio. No help.Any ideas? It only fails about 5% of the time. Most ACT instruction come across OK.Thanks,Jim