I'm throwing this out there as I'm seeing this as a new FPP user. Here's some context. I've been using the latest version of LOR S3 for many years and have about 24 sequences I've built out over the years. I decided this year to start using xLights as my sequencer and did a data layer import of all of my LOR S3 sequences into the latest version of xLights. To add a bit more context, I've been using LOR S3 player in previous years and I did tests in the latest version of xLights, not just using a visualizer/layout but with my controllers and lights...and I've never seen any sync issues in the LOR S3 or xLights players.
So, I then decided to move down the FPP path as many of you have. All installed well and looked good. I'm running on a Pi2 with 32GB flash for the appliance and 64GB USB Flash (high end/fast) for the media. I then started testing and went through playing all of my sequences with the controllers and lights. To clarify again...These are all fseq files from data layer imports in the latest version of xLights from LOR S3. The result is I found that all of my data layer imported sequences have my lights ahead of my audio by ~300ms. So I started working with the team over at Falcon and we went through many different tests...only one proved to yield different results. If I create a new xLights sequence without any import from LOR S3 I don't have any sync issues. So the only thing I can think of is there is something happening when the fseq is created and a data layer import is included...the strange thing is, these imports work just fine in the xLights player.
So at this point...I'm at a loss. I have a couple different fseq's, xml and lms files I'm willing to share for someone to test with and see if they are getting the same results as me. The falcon folks have seen the same delay from my fseq's with the exception of the one that didn't include a data layer import. I'd love your thoughts

Here is the link of the issue on the Falcon forums if you'd like to read further...thanks for your time in reading this!
http://falconchristmas.com/forum/index.php/topic,3190.0.html