Supernatural actors and their characters' younger counterparts matched to age. Always been impressed by the casting for flashback scenes, especially for Sam. Colin Ford was younger so it looked even more believable.
Ambient-Mixer.com has a section dedicated to the background sounds of fictional worlds, so you can study to the sounds of the Gryffindor common room, read in Belle’s library, or browse the Internet while you’re being chased by a hoard of Dothraki. Source Source 2