Surround Sound: Calibration

Surround Sound is a speaker system usually containing 5 to 7 different audio channels, plus a discrete LFE (low frequency effects) channel. It’s main intention is to immerse the listener/viewer into a soundscape as they experience multimedia productions (such as film, music & games) by using separate sound sources in order to create a more ‘three dimensional’ soundscape. Surround Sound is commonly used in cinemas and home theatre systems.

Not only is it possible to watch and listen to multimedia with surround sound, but it’s also possible to feel it. For example. If a car on the television screen flies past, you can hear it coming from the back left, passing, and then exiting off screen from the front right. An excellent example of a 5.1 surround sound audio mix can be found in the 2013 sci-fi space stunner “Gravity”.

SoundWorks Collection: The Sound of Gravity from Michael Coleman on Vimeo.

A very important aspect of Surround Sound is Calibration, which is a process that ensures the speakers are set up in such a way to make the viewing location also the best possible listening location, which is commonly known as a ‘sweet spot’. In studios, the ideal sweet spot would be where the console operator sits at the desk, or just a little bit behind. In theatre systems, both home and cinema, the calibration would be configured in such a way to give the majority of the audience the best possible listening experience, so the speakers will be aimed at either the middle of a couch or the middle of the cinema room.

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TurboFuture – Home Theater & Audio

Calibrating 5.1 and up in the studio is possible using a DAW such as ProTools, a signal generator, measuring tape, sticky tape, a mic stand, an SPL meter, hearing protection, and of course, a surround sound speaker system. Once your speakers are all set up, create a 5.1 session in ProTools, then assign a signal generator plugin insert on a new 5.1 audio track. Power on the SPL meter and tape it to the mic stand, then position the mic stand exactly where you want the sweet spot, at a listener’s head height. Put on your hearing protection and then start hard-panning the signal to each speaker, making sure the speakers are in the right places by checking that the distances from each speaker to the SPL meter are all equal, and that the meter is getting the same reading from each speaker. This will require moving the speakers around until the right results are achieved.

Calibration is important because it allows the console operator in the studio to accurately monitor their mix while mixing for 5.1 and up, and is especially important when it comes to moving from one studio to another, because the next studio you take your 5.1 session to could have a different monitor setup/calibration, so it is important to consider this translation between different speaker setups in different control rooms.

References:

Coleman, M. (2013, October, 4) SoundWorks Collection: The Sound of Gravity [Vimeo Video] Retrieved from https://vimeo.com/76123849

TurboFuture (2017, July, 20) How To Set Up & Calibrate 5.1 / 6.1 / 7.1 Speaker Surround Sound System [Web Article] Retrieved from http://turbofuture.com/home-theater-audio/How-to-set-up-and-calibrate-your-home-cinema-or-theater-surround-sound-system 

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Surround Sound: Calibration

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