I think I know what you mean - the dpi settings for saving a file? If so, go to Distiller (in Acrobat, it's under Tools, then click Disttiler), Setting, Job Option. Under the General tab, there's a dpi resolution setting, then under the Compression tab, there's more dpi settings. You'll probably just have to play with the settings to find out what works best for you.
Hope this helps!