when you have done you're ramp slo mo, you go to the top bar and composition>add to render queue.
then a render queue tab will pop up, with the clip you just added inside of it. The bottom line of the file description will have a blue underlined, "lossless" button, which Issac Coy was describing. Click that
On the bottom portion of the pop up box, an Audio section will be outlined. You can check the box in the bottom left, and it will add the audio to your clips. don't forget to render them out.
you're all set to go
