I stumbled upon this question while I was having Audio issues myself, I was editing a multicam sequence at first but switched because I was having some audio sync issues. My Sequence was about 50 min in total and in the past had only taken a few min to export on my souped up Mac Pro. Later on after my last export, I discovered that my audio was out of sync somehow AGAIN so I had to go back through and Match Frame on all the clips. When finishing I tried to export the Sequence to find that it was going to take over 8 hours to render Audio Previews. What I did was select all (audio and Video) and switch it to Multicam and Flatten Audio. After this my audio render for 280 clips was less then 2 min. Hope this helps. Nick
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