Tuned In is an achievement in Halo 3: ODST and Halo: The Master Chief Collection. The achievement the player unlocks three Audio logs in the campaign. In the original game it is worth 15 gamerpoints and is represented by a green square with audio lines going across it, the number 3 in the lower-right corner, and a picture of the Superintendent, looking bored, in the background. In The Master Chief Collection the achievement is only worth 5 gamerpoints and is represented by a sequence of images from Sadie's Story overlaid with an image of a quizzical Superintendent.
The achievement is awarded when the player unlocks their third terminal, regardless of which terminal in the hub that is. For terminal locations, see here.