Ambient sounds is the sounds of a given location or space in the environment. The sounds can include things such as wildlife, wind, rain, distant traffic etc.
For example, in the film 'Hunger Games: Catching Fire' when they had a forest scene they'd take a microphone to a location (jungle, ocean) which would give them good quality sounds and would record them themselves, he used libraries as well but his helped supplement and this meant they didn't have to completely rely on sound libraries. This helped them give a better atmosphere and show claustrophobia. It also allowed them to build up the 'world of the sound' very early on in the process so they didn't have to wait till the end and start over as such. Recording the ambient sounds also allows for tiny details to be heard. In the arena scenes it helped allow them to intensify things and they wanted to make it really dense, really busy and add a claustrophobia to you could get a feel of being with the characters. It helped it become unique to its location. The benefit of using microphones on location instead of library is that it allows you to not have to do what is called 'looping' which is where characters rerecord their dialogue which is then looped on top of the footage. While recording sounds of location, they would use 2 sets of different microphones and separate them about 70 feet apart, this allowed to get sounds with different qualities as they both picked up different sounds. It also gave them a wider range of sounds to use. Hard cuts aren't often advised for sound mixing, for example in Hunger Games if a shot is done in the arena and then after that, is shot in the capital an ambient sound, such as wildlife, is slowly added which helps interact the audience instead of using a hard cut. The software used for Hunger Games: Catching fire is Dolby.
2) Recording Dialogue
Recording dialogue is much more difficult to be done rather than ambient sounds. This is because of reasons such as ambient noises interfering with the recording, which can effect the quality of the dialogue. As well, sometimes if the camera is a fair distance from the characters speaking, and you had no form of microphone, then often the problem can be that the voices are found very quiet on the footage. This can be over come by potentially using microphones or looping which is where actors re-record their lines in sync while watching their original performances in looped playback, this helps match the wording and lip movement. Ambient noise is important when filming a conversation scene because it helps create an atmosphere, avoids silence in the background and possibly echoing. It can also help the audience understand the situation, depending on what is happening, for example if a tense sound was used, this would allow the audience to know something was going to potentially happen. When they were filming the Hunger Games: Catching Fire, for the jungle locations, when filming they always had a constant presence of canopy leaf movement as useful as this is for the ambient noise, it could have effected recording dialogue.
