Abstract
Surround Sound
I always wondered how they get those sounds to separate the way they do in theaters as well as in home theaters. It is interesting to me how we can hear audible cricket noises on the left side of the room and hear a whirring noise or footsteps on the right side of the room while there are people having a conversation in the front part of the room. The interesting part is that we feel like we are actually in the movie in real time. That is what interest people the most, how realistic the sounds are and the feeling they give the audience of actually being in the midst of a gun fight or a World War II battle. Try watching Saving Private Ryan with a high quality surround system and one will wonder if they are really getting shot at or if they are still watching a movie, since one can hear bullets blazing past the ears in beautiful realism.
For the research aspect, I am searching in audio visual magazines, various online and library journals that have similar research on surround sound. Even today, engineers are still thinking of new ways to make the sound even more crisp and clear for an even more realistic theater experience. One day, one will watch a movie and it may seem like an alien is right next to their ear breathing heavily down on their neck.
For the implementation aspect, I will use Max/MSP to simulate surround sound by making my own code that mimics the surround sound mechanism. I will implement codes that involve spatialilization and the Doppler Effect, the transference of sound through different channels, coding and encoding sound for 3-D sound effects, and use some of the examples the professor discussed in recent lectures regarding sound spatialization. For example, I will have a sound file and try to split that file into different channel and put them through the channels giving me a sense of surround sound. I think the hard part will be trying to split a sound file into different parts since that sound file has already been made into a file. It is not a file that can be coded and decoded such as they do in normal surround sound applications. I will use filters to separate sound into different frequencies and then output out each frequency through different channels. A problem I may encounter is that most low end earphones are only 2-channels, the left and the right. I may have to use the teaching assistant’s speaker settings in his office or the professor’s speaker system to test my program.
Currently my research is still in its development phase and
I am still working on the Surround Sound aspect through Max/MSP. Previous lectures and assignments on spatialization and Doppler Effect will greatly aid me in
completing my research. The main aspect of my research revolves around getting
4 or more channels out of a 2-channel system such as headphones and
speakers.
As I was continuing my research on surround sound, I came across the Dolby Digital website. They have this interesting demo of their two speakers surround sound system or their surround sound headphones. I was skeptical at first, but after one tries the demo, they will have their minds blown. They call it their “Virtual” speaker system. Achieving surround sound from just two speakers is surreal and amazing in many aspects. As an add on for my project, I also want to mimic Dolby’s “Virtual Speaker” technology and use Max/MSP to test, apply, and implement my own program in very much the same way they do, but on a less complicated level.
I have been focusing the bulk of my research on phase shift,
quadraphonic and stereophonic systems, FFT, low pass and high pass filters to decoders,
encoders, and spatialization among others.
Key Word search list: Surround Sound ,perspective panning,
3-D sound, spatialization, sound spatialization,
low pass filter, band pass filter, Decoders and Encoders, Phase Shift, Audio
Localization, Sound Localization, Quadraphonic
listening space, Ambisonic, Stereophonic
Bibliography of Sources
Although there are so many sources for Surround Sound, I found the most info from various websites. The problem here is that some websites may not be as reliable as others concerning the basic info and degree of understanding to which they make their websites. So, I take this into consideration as I continue my research. These are some of the sources I have used so far.
Books
[1] Francis Rumsey, “Spatial Audio,”
[2] John Garas, “Adaptive 3D Sound Systems,”
[3] John Garas, “Adaptive 3D Sound Systems,”
Universiteit
[4] William G. Gardner,
“3D Audio Using Loudspeakers,”
Java Applets that
show how LP and HP filters work!
http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/experiment/lowpass/lpf.html
http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/experiment/highpass/hpf.html
Dolby.com (various
web articles, in PDF format)
http://www.dolby.com/assets/pdf/tech_library/2_Surround_Past.Present.pdf
http://www.dolby.com/assets/pdf/tech_library/148_563_2.Manual.pdf
http://www.dolby.com/assets/pdf/tech_library/53_EvolutionOfSound.pdf
http://www.dolby.com/assets/pdf/tech_library/44_SuroundMixing.pdf
http://www.dolby.com/assets/pdf/tech_library/42_DDFAQ.pdf
http://www.dolby.com/assets/pdf/newsletters/358_wb.nw.0211.journal.pdf
Howstuffworks.com:
Surround Sound (accessed
By Tom Harris
http://electronics.howstuffworks.com/surround-sound.htm
Chris
Kantack's Surround Sound Info. Source (accessed
http://kantack.com/surround/
Extremetech.com
(online article, accessed
By Leslie Shapiro
http://www.extremetech.com/article2/0,1558,12166,00.asp
Program
-Work in progress. Check
back later, updates soon to come.