The topic this week is Output and we will explore the following focus areas:
SPEAKERS | MONITORING | FORMATS | MASTERING
FOCUS AREAS IN DEPTH
OVERVIEW SPECIFICS EXPLORE
SPEAKER SYSTEMS - As we strive to be professional sound designers, quality speakers are critical to hear the given content in a mix and to edit accurately. Professional studio monitors might appear similar to speaker systems you may have connected to your home theater, but professional monitors are designed from a totally different approach. Even though the final selection of a given speaker system will vary from user to user as to what just “sounds good,” speakers can be objectively evaluated based around various specifications.
Frequency Response - Ideally speakers will have extremely flat response across the frequency spectrum. This is important for critical listening applications as sound designers need to know exactly what is working and what isn’t concerning a mix. Considerations also need to be made for the delivery. the vast majority of consumers will not be listening to content in a controlled environment with accurate listening devices. If sound is mixed in an inaccurate environment or with consumer speakers or headphones for example; sound will be reproduced for the end listener in unexpected, and potentially damaging ways, not only for the equipment, but also their hearing.
Linearity - Extending the frequency response discussion, system linearity is a measure of how frequencies will be reproduced based on input. For example, if sound being fed to the speaker is either louder or quieter than what is being played back, sonic information will either not reach or be perceived as overpowering to the listener.
Polar Response - It may becoming clear that speakers are essentially the reverse of the mic in that they play back sounds instead of recording them. Just as microphones have a polar patterns that determine how sound will be captured, polar response for speakers reproducing the sound is just as critical. If the polar response is too wide, when placed in a given studio, the system may produce unwanted reflections. Inversely if the response is too narrow, listening position will be too specific and difficult to monitor as it may not allow for variances in listening position.
MONITORING - As the last piece of the audio chain, the speakers are a critical tool in accurately listening to the content sound designers work with. Placing speakers in the studio or playback environment is just as critical in speaker selection. There are various methods in creating sound stages needed to edit, mix and evaluate the final product whether it be stereo, surround and beyond.
Near-Field - To combat unwanted reflections from the room, speakers are placed near to the listener as to hear more direct sound. Commonly seen atop a console’s meter-bridge, near-field monitors are generally small speaker systems, comparable in size to “bookshelf” sized speakers sold to consumers. Make no mistake these are not the same thing! True near-field monitors will have an exceptionally flat response, good sensitively with modest power requirements, and proper dispersion for accurate stereo imaging.
Stereo - Stereo is a two-dimensional format with two discrete speakers providing a sonic image with width and depth. To accurately monitor stereo, symmetric placement in a room should create a triangle formed by the left and right speaker and the listener at the point. The speakers should be placed and equal distance from each other and the distance to the listener.
Surround - Although not truly three-dimensional, surround sound attempts to create more immersive environments for the listener. The listener is placed between speakers as opposed to in front of them like a stereo environment. As a baseline standard, surround sound is mixed in an environment called 5.1 with six discrete channels. These channels extend the stereo environment from left and right, adding surround left and right channels, center channel (mainly for dialogue), and a low frequency effects channel, which is the .1 of the specification.
FORMATS - Careful consideration should be made when exporting audio mixes. There are a number of formats that each have specific advantages and disadvantages. While others are proprietary to specific operating systems and devices. The main difference between formats is whether they are uncompressed or compressed in a lossless or lossy format.
Uncompressed or raw audio is digital information referred to as LPCM, or Linear Pulse Code Modulation. This type of audio found on Compact Discs can also be passed to the .wav and .aiff file formats to add metadata to the file making them more useful in practical applications.
Lossless means file are compressed in a way that preserves original fidelity and are an exact copy of the original data with no data loss. Common file extensions include .flac (Free Lossless Audio Compression) and .alac (Apple Lossless Audio Compression)
Lossy formats compress the files size, sometimes dramatically by removing data from the original copy to achieve the desired compression. Common formats include MPEG-1 Layer 3 (.mp3) and AAC (Advanced Audio Coding)
Lossy audio compression formats allow for more distribution of music and other digital media, but could it also be leading to a detrimental listening experience? The Distortion Of Sound is a short documentary presented by Harmon and offers a discussion with industry professionals on the subject.
OVERVIEW SPECIFICS LOUDNESS EXPLORE
MASTERING - Is the final process in professional audio delivery. This is done after the final mix is complete and usually performed by a separate engineer. In music production, mastering engineers add final EQ and compression to create balance and consistency in loudness from song to song for a cohesive album. In the case of film and television, a similar approach is taken making sure audio levels fall within various parameters established by governing standards organizations.
Stems - Individual mixes of element groups in the larger mix. These audio tracks are created by routing audio signals to bus tracks which break out and aid in the organization towards a final mix. A simple example for a film application would be Dialogue, Sound Effects, Ambience, Music. Even though there could be countless individual tracks for each group, each of those tracks is sent to the bus track, which is later mixed with the other stems.
Normalization - This highly debated process, adjusts the levels across the entire digital audio file to a target level. The process looks at the existing highest peak and raises gain across the entire file relative to the target, so the existing peak will be at the set target level. Even though the entire file undergoes gain changes, this process allows audio to retain its original dynamic range.
Loudness Standards - Governing technical standards organizations (Including, but not limited to the Audio Engineering Society (AES), European Broadcasting Union (EBU), International Telecommunication Union (ITU) and Society of Motion Picture and Television Engineers (SMPTE)) have devised regulations as way to insure that audio will be consistent and fall within target ranges. Universal standards insure a means of protecting consumers ears and hearing. These standards also provide consistent playback levels for comfortable enjoyment of audio content through various program delivery methods.