Surround Sound Flashcards
Ls
Left surround
Rs
Right surround
Mono-pole speakers
Sound is only emit from the front
Di-pole speakers
Sound is emitted from the two sides
Tri-pole
Sound is emitted from both the two sides, and the front
Music-specific rooms tend to use what type of speakers
Mono-pole
Surround sound-specific rooms tend to use what kind of speakers?
Multi-pole
In a stereo mix, how is the ‘centre’ sound created?
Sending the same audio signal into both the left and right speakers and equal volume
Phantom centre
A faux centre created in a stereo mix by sending sounds panned equally between the left and right channels with equal volume, creating the illusion of a centre speaker
Sample rate of SACD
2.8224 MHz
Maximum frequency response for Surround channel in Dolby Surround mix
7 kHz
Dolby Digital compression ratio
11:1
DSD
Direct Stream Digital
DTS compression ratio
3:1
SDDS compression ratio
5:1
Film format that optically prints audio tracks on the outer edge of 35mm film
SDDS
Maximum sample rate of Blu-ray
192 kHz
Possible placements for the two extra speakers in a 7.1 system
- Left and right side
- Left centre and right side
- Rear centre channel and VOG
T/F: Dolby Pro Logic is the consumer decoder for surround sound
True
ITU-R BS.775-1: Engineer should be placed where amongst the speakers
Equal distance from the 5 main channel speakers
Dolby Surround: A signal that is identical in both the Lt & Rt, and 180˚ out of phase goes to this speaker
Surround
ITU-R BS.775-1: How many degrees off centre should the left and right speakers be when mixing in 5.1?
30˚
T/F: The term ‘codec’ only applies to digital soundtracks
False - codecs have been used to encode and decode sound for film, analog VHS tapes, etc
THX
A certification process for precise audio reproduction characteristics
2 other names for the Grid Panner
- X/Y panner
2. Etch A Sketch panner
VOG
Voice of God speaker
VOG placement
Directly overhead
Dolby Digital soundtrack is also referred to as these
Audio Codec-3
AC-3
.ac3
On a surround monitor controller, inputs that are greater than 2 channels are called:
Wide inputs
Codec that allows you to provide surround sound from a 2-channel mix
Dolby Pro Logic II
ITU-R BS.775-1: How high should speakers be when mixing in 5.1?
All the same height
T/F: THX is a surround sound encoding format
False
T/F: Not all Dolby Digital soundtrack are matrix encoded
True
In Pro Tools, what must the Centre Percentage control be set to to achieve a ‘true centre?’
100%
T/F: Bass management is part of the mixing process
False
T/F: The LFE channel is also known as the subwoofer channel
False - there is no such thing as a ‘subwoofer channel.’ The channel is LFE and is reproduced by a subwoofer
Surround playback format that mirrors 5.1 but adds a rear centre surround channel
6.1
Amount of channels of audio that are produced by the Dolby Surround decoding process
4
Divergence is commonly referred to as
Bleed control
T/F: Surround systems that use a dedicated LFE channel are called dot one systems
True
ITU
International Telecommunications Union
On a surround monitor controller, listening to a multichannel mix in a lesser channel format is called
Downmixing
Typically, how many channels are in a Surround Sound system?
Any amount higher than 2
LFE channel plays through this speaker
Subwoofer
SMPTE channel order standard
- L
- R
- C
- LFE
- Ls
- Rs
DTS channel order standard
- L
- R
- Ls
- Rs
- C
- LFE
Dolby / Film channel order standard
- L
- C
- R
- Ls
- Rs
- LFE
Output of Dolby Surround encoder is called
LtRt
2 reasons why Blu-ray and DVD often contain soundtracks with data compression
- Space on the disc is limited, and digital video occupies a large amount of the available space
- Players requiring a laser to read information from a disc have limited bandwidth in their data streams which must be divided for the picture and sound
ITU-R BS.775-1: Ideal placement for the surround speakers while mixing in 5.1
110˚
LFE
Low Frequency Effect
Systems that are .0
Have no dedicated LFE channel
Playback format
The channel systems, such as 4.0, 5.1, 7.1, etc. This will also indicate where speakers should be positioned in the room
Delivery format
How the final surround mix is delivered to the consumer, such as DVD, Blu-ray, VHS, etc.
Quadraphonic
4.0 playback system from the 70s/80s and the first multichannel system designed for music delivery to consumers
L, R, Ls, Rs
LCRS
4.0 playback system that is still widely used in surround sound
5.0
Playback format that combines Quadraphonic and LCRS, with 3 front speakers L, C, R and two surround speakers Ls and Rs
5.1
Playback format that is exactly like 5.1 but adds a dedicated LFE channel
6.1
Playback format that is exactly like 5.1 but adds a Center Surround speaker. This gives us 3 front speakers L, C, R, 3 surround speakers Ls, Cs, Rs, and a subwoofer
7.1
Playback format that is like the 5.1, but adds two more speakers in the back, and moving the surround speakers to the sides. This gives us 3 speakers in the front L, C, R, 2 speakers on the sides Ls and Rs, and 2 speakers in the rear Left Back and Right Back. Lastly .1 means there is a dedicated LFE channel, giving us a subwoofer
Surround Sound Monitor Control: Speaker Selection
Controller provides the ability to switch between multiple multichannel speaker systems, as well as to make different combinations
Surround Sound Monitor Controller: Speaker Muting
Most consumer surround playback systems do not have the capability to mute individual speakers, but it is mandatory for a professional surround sound monitor controller to provide this ability
Downmixing
Checking a multichannel mix in a playback format with fewer channels
Centre Percentage to achieve a True Centre
100%
Centre Percentage to be equally in the true centre and phantom centre
50%
Centre Percentage to achieve a Phantom centre
0%
Typical frequency to set the LFE split at
80 Hz
Encode
The process of packaging the audio for delivery
Decode
Unpackaging to be able to playback
Codec
A process that a system uses to be able to encode and decode a delivery format
Discrete systems
Keeps the channels separated
Multiplex
Ability to combine multiple channels into a single channel of information
Matrix systems
Packaging surround sound mixes into two channels, allowing the audio to sound correct in stereo; but if played through equipment that can decode the surround sound mix, it can be expanded back to its original multichannel format
T/F: LtRt can be heard as a traditional stereo mix
True
What happens if LtRt is sent through a matrix decoder?
Matrix decoders recover the additional surround channels such as the centre and surrounds
How does the Matrix decoder direct the 2-channel mix into a multichannel mix?
Left: Any signal that is sent only to Lt
Centre: Any signal that is sent equally to both Lt & Rt and is IN phase
Right: Any signal that is sent only to Rt
Surround: Any signal that is sent equally to both Lt & Rt and is OUT of phase
Upmixing
When a single-ended matrix decoder derives a multichannel output from stereo mixes that were never mixed or encoded for surround sound