Audio not playing back in preview properly, (read below)

Many beginners step into a similar problem. Mostly it's in the understanding on how AE works:

AE focuses on playing back your composition no matter how complex it is, or how many effects you have applied. But before this can be done in realtime, AE needs to render the frames. Very soon this rendering took longer than realtime, leading to a playback framedrop (I've seen everything down to 0,01 fps).

Back "in the old days" you usually hit 0-button on the num-block of the keyboard and than wait for minutes until the preview for a couple of seconds was rendered.

Now you hit the spacebar and you expect a playback behavior like in premiere or any other NLE. But it highly depends on your system, hardware, software, and of course your composition, if this is even possible or not.

Since CC2015 AE pitches the audio down to keep it in sync with the playback speed. Before CC2015, audio was just muted.

You can go back to the "audio muted" option in the preference menu. However, the outcome will be, that after a few seconds you just don't hear any audio anymore. If you only want to hear the audio, you can press the comma-button on the num-block. AE should be capable of playing this without a framedrop.

I suggest that you dig a bit into preview-rendering to understand how this is meant to be used. There are several options to improve playback speed - the most common might be to reduce preview-resolution.

For more help, please provide the information Mylenium asked for.

Cheers,

Martin

Impossible to say anything. You have not provided even the tiniest bit of useful information like system information, preview settings, audio preferences, files used in the project, composition settings and whatnot.

Mylenium