Loud pop at beginning of video, tried multiple export options, losing mind

I have a 5 minute movie montage that has a loud popping noise at the very beginning once I finish exporting. I have experienced this issue before and thought I had fixed it with this project, but now it's happening again, and I have no idea why or how to fix it.

Here's all the info:

Project Properties:
1280x720p
25 fps
Stereo 48 khz Apple ProRes

The music in the piece was ripped from CD using iTunes as an AIFF file, 1.5mpbs 48 khz 16 bit 2 channel PCM

NOW...Like I said, I was having issues with this and other projects previously, but I thought I had fixed it by making sure the audio bitrate for the project was the same as the bitrate for the exporting option I chose. Now, for some reason, I'm hearing the pop again. The settings I am using are:

Format: Video and Audio
Codec: H.264
Resolution: 1280x720
Audio file format: QuickTime Movie (AAC) (48khz)

I'm stuck. Any ideas?

Anyone?

Does your audio have a fade at the beginning?

It didn't initially. I tried adding a fade to see if that would fix it, but no luck.

If I get this right you don't hear any pop when playing your edit in FCPX, but you do hear the pop in QT player after you have exported your Project to H.264, correct?

If so, how do you export from FCPX?