This presentation gives you the basic idea about surround system. Various aspects to be considered while designing surround system and it's various formats.

1. SEMINAR
ON
SURROUND SOUND
SYSTEM
Guided By : Prof. Amol C Wani
Presented By: Chetan V Gakhare

2. Content:
 What is Surround sound?
 Early surround sound
 Generalized Surround sound arrangement
 Creating surround sound
 5.1 Channel surround sound
 Other surround sound specifications
 Design of home theatre using HDMI
 Surround Sound Formats
 Applications
 Conclusion
 References

3. What Is Surround Sound?
Surround sound is a technique for enriching
the sound reproduction quality of an audio source
with additional audio channels from speakers that
surround the listener, providing sound from a 360°
radius in the horizontal plane (2D) as opposed to
"screen channels“ originating only from the
listener's forward arc.

4. Early Surround Sound
 The first use of surround sound
was in 1940, for the Disney
studio's animated film Fantasia.
The sound was diffused
throughout the cinema, initially
by an engineer using some 54
loudspeakers.
 In 1978, Superman movie
“Apocalypse Now “ made the
first formal release of surround
sound in cinemas with three
channels in the front and two in
the rear by Dolby lab.

5.  Center speaker carries most of the dialogue and
part of the soundtrack.
 Left and right front speakers that carry most of the
soundtrack and may carry parts of the dialogue
 Pair of surround sound speakers that is placed to
the side (and slightly above) of the audience to
provide the surround sound and ambient effects.
 Finally, a subwoofer can be used to reproduce the
low and very low frequency effects (LFE) that
come with certain movies
Generalized Surround Sound
Arrangement

7. Creating surround sound
 The first and simplest method is using a surround
sound recording microphone technique
 A second approach is processing the audio with
psychoacoustic sound localization methods
 A third approach, based on Huygens' principle,
attempts reconstructing the recorded sound field
wave fronts within the listening space; an "audio
hologram" form.

8. Monophonic Sound
 Monophonic sound is a single-
channel, unidirectional type of
sound reproduction.
 To the ear, all the elements of the
sound, voice, instruments,
effects, etc... appear to originate
from the same point in space.

9. Stereophonic Sound
 The main aspect of Stereophonic
sound is the division of sounds
across two channels.
 The recorded sounds are mixed
in such a way that some
elements are channeled to the
left part of the soundstage;
others to the right.

10. Extracts Five audio channels :-
 Two channels for speakers
at the front—left (L) and right
(R).
 One channel for speaker at the
center—center (C).
 Two channels for surround
speakers at the rear—surround
left (LS) and surround right
(RS).
 One low-frequency effects
channel (LFE).
5.1 Channel Surround Sound
( ITU-R BS. 775-1 Standard)

11. 3.0 Channel Surround Extracts 3 audio
channels :-
 Two channels for
speakers at the
front—left (L) and
right (R).
 One channel for
surround speaker or
speakers at the rear—
surround (S).
Other surround sound
specifications

12. 4.0 Channel Surround
(analog matrixed/discrete:
Quadraphonic)
Extracts four audio
channels :-
 Two channels for
speakers at the front—
left (L) and right (R).
 Two channels for
surround speakers at
the rear—surround left
(LS) and surround right
(RS).

13. 4.0 Channel Surround
(analog matrixed: Dolby Pro Logic)
Extracts four audio channels :-
 Two channels for speakers
at the front—left (L) and
right (R).
 One channel for speaker at
the center—center (C).
 One channel for both
surround speakers at the
rear—mono surround
channel (S).

14. 6.1 Channel Surround
(analog matrixed: Dolby Pro Logic IIx)
Extracts six audio channels and
one low-frequency channel :-
 Two channels for speakers at
the front—left (L) and right
(R).
 One channel for speaker at the
center—center (C).
 Two channels for surround
speakers at the sides—side
left (LS) and side right (RS).
 One channel for surround
speakers at the rear—back
surround channel (BS).

15. 7.1 Channel Surround
(digital discrete: Dolby Digital Plus, DTS-HD,
Dolby TrueHD)
Delivers seven audio channels and
one LFE channel :-
 Two channels for speakers at the
front—left (L) and right (R).
 One channel for speaker at the
center—center (C).
 Two channels for surround
speakers at the sides—left
surround (LS) and right
surround (RS).
 Two channels for surround
speakers at the rear—left back
(LB) and right back (RB).

16. Zero-based order
within multi-
channel
mp3/wav/flac data
stream.
Order within
DTS/AAC. Channel name
Color-coding on
commercial
receiver and
cabling
0 1 Front left White
1 2 Front right Red
2 0 Center Green
3 5 Low frequency Purple
4 3 Surround left Blue
5 4 Surround right Grey
6 6 Surround back left Brown
7 7
Surround back
right
Khaki
Channel Identification

17. Design Of Home Theatre System
Using HDMI Transreceiver

18.  This system “Home Theatre In Box” generally
include a multichannel audio amplifier and a
surround-sound speaker system for playback of
audio.
 In addition, these system usually include a DVD or
Blu-ray™ video player. HTiBs ease installation and
power matching between the video player,
amplifier, and speakers. HTiBs principally process
audio; the video is passed through to the TV over
the HDMI interface.
 A new feature in the HDMI specification provides
for an audio return channel (ARC)—to allow the
HTiB to process audio from the downstream device.

19.  Another use of an HDMI transceiver within an
HTiB is to extract the HDMI audio for processing
with a digital signal processing (DSP) chip. The
audio can then be reinserted into the HDMI stream
to the TV.
 Since many TVs cannot handle multichannel audio
formats, the DSP chip can downsample the audio
to stereo and then reinsert the audio into the HDMI
link to the TV.

20. Surround Sound Formats
 Dolby Pro Logic
 Dolby Digital
 DTS
 THX Surround EX
 SDDS

21. Dolby Pro Logic
 It is the simplest, cheapest format.
 It has 4 channels that are compressed into
two analog channels, so you can record it
on your stereo VCR and it can also
broadcasted even over analog radio or
cable TV.

22. Dolby Pro Logic

23. Dolby Digital
 It is a 6-channel format, referred to as 5.1-
channel
 Advantages over Dolby Pro Logic include
the fact that all channels are digital,
discrete and 5 of them are full-bandwidth.
 Additionally, the surround speakers use
separate left and right channels (stereo).

24. DTS
 DTS is also a 6-channel format (5.1-
channel).
 The main difference from Dolby Digital
is that DTS uses less compression thus
providing marginally better sound.
 DTS is less widespread than Dolby
Digital.

25. THX Surround EX
THX Surround EX takes the Dolby
Digital signal and creates another
additional matrixed channel, which is then
sent to one or two surround speakers, thus
giving a 6.1 or 7.1 sound.

26. SDDS
 The latest entry in cinema digital sound,
Sony Dynamic Digital Sound® (SDDS)
 It boasts five separate channels at the front
of the theater as well as left and right
surround channels, for a total of eight
available channels including the
subwoofer.

27. Applications
 Cinema and Soundtracks.
 Creation of audio environment for different purposes.
 Integrate voice-based comments in an archeological site
or monument.
 Video Game Consoles.
 Personal Computers.
 Enhanced situation awareness in military and public
safety applications.

28. Conclusion
Today's surround sound experience is the result
of decades of evolution. The surround sound
experience is now easily accessible, practical,
and affordable for the consumer.
Go get surrounded..!!!

29. References
 Technical Document AESTD1001.0.01-05 multichannel
surround sound systems and operation
 HDMI Transceivers Simplify the Design of Home Theater
Systems by Ian Beavers, Joe Triggs, and Lie Dou, Volume
45 – February 2011
 “Understanding Home Theatre”, Curt Robbins, 2015
edition.

30. THANK YOU