Ian F. Hunt

Cinematographer and Filmmaker

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Future Cinema – Digital Cinema

7.1 Surround Sound

7.1 Surround Sound

Digital Cinema

Cinema – Digital Cinema conversion

With the ongoing process of converting Cinemas to Digital Technology this opens up new possibilities for sound technology. The majority of Digital Cinemas offer 5.1 Surround Sound that is 6 channels of audio and now many offer 7.1 Surround Sound, 8 channels of audio. The additional speakers are either positioned high above the existing front speakers, that is Front Left and Front Right, alternatively they are positioned mid-way between the front and rear speakers.

Dolby 7.1 Surround Sound. Site Accessed 23/11/2011
http://www.dolby.com/us/en/consumer/setup/connection-guide/home-theater-speaker-guide/index.html

Digital Cinema – Future Cinema will be able to deliver a growing number of audio channels as the technology advances. For this project we think that some of these additional audio channels could be used to deliver a more immersive audio experience directly to individuals in the audience.

X Rocker Gaming Chair

X Rocker Gaming Chair

As an example of this we can look at the Games industry and a relatively low cost piece of Technology the Gaming Chair.

These come complete with their own built in 2.1 Sound Systems including a sub-woofer and the ability to deliver additional sensory experience using rumble and vibration to create sensation of movement directly related to sound levels and frequency.

X-Rocker Gaming Chairs site Accessed 23/10/2011
http://www.xrocker.eu/x-rocker-vision-pedestal-54-p.asp

A cinema fitted out with these types of chairs could deliver a whole new experience to the cinemas audience.

For the purposes of the project the chairs speakers provide the means to deliver the additional sound tracks we conceptualised, to be able to deliver a personal message, a sound clip direct to the audience in very close proximity – the whisper in an ear, the gun shot fired inches from your ears. Such a close proximity in the delivery of sound to the ear would also be felt as well as heard as the compression of loud sound waves or sound coming from a location in  close proximity to the ear would create air pressure effectively pushing against the ear drum, the sensation of wind blowing in the ear.

I’ve thought of a side benefit of using these chairs which would be to provide additional sensations using the built in sub-woofer to create rumble and vibration, in fact feeling as well as hearing the sound. This could be a possible update to Sensurround introduced for a small number of films in the 1970’s for example ‘Earthquake’ released in 1975.

The failing of Sensurround was that it relied on using additional Bass speakers and playing low frequency sound at high decibel levels which could be heard in adjacent theaters ruining the audience experience due to hearing the sound of another film through the walls of the Cinema.

My idea using these chairs would mean that the the high decibel level could be avoided and yet still get the vibration effect.

Our binaural soundtrack could be sent to the speakers in these chairs negating the need to use headphones. Although some of the effect would be lost by using speakers the close proximity of these speakers to the ears and combined with some form of sound processing to simulate the 3D Stereo effect and the brains ability to process sound information known as “interaural level differences (ILD) and the interaural time differences (ITD) that characterize two-eared human hearing” Ambiophonics. Site Accessed 23/10/2011 – http://en.wikipedia.org/wiki/Ambiophonics

The Human Ear or rather the human brain can determine not only where a sounds location originates from, anywhere in a 360 degree perspective, but can in fact localise and process sound in a sphere. The visual medium still has some way to go before it can deliver a cinematic experience based on a humans spherical perception.

Future Cinema – Links to Related Blog Entries

  1. Future Cinema – Project Conclusion
  2. Future Cinema – Sound Effects
  3. Future Cinema – Digital Cinema
  4. Future Cinema – 5.1 Surround Sound
  5. Future Cinema – Binaural Sound – Digital Sound Recording
  6. Future Cinema – 360 Degree Camera Mount
  7. Future Cinema – Learning Agreement (Updated)
  8. Future Cinema – Audio / Film Script 1st Draft
  9. Future Cinema – Binaural Sound Recording
  10. Future Cinema – The Film Pitch
  11. Future Cinema – does it have one?

 

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Future Cinema – Binaural Sound – Digital Sound Recording

Digital Sound Recording

For our group project we are investigating methods of digital sound recording using both a Digital Audio Recorder (Fostek FR-2LE field recorder ) and recording directly to a MacBook Pro’s line input.

Digital Sound Recording direct to MacBook Pro line input

Fig 1.0 Digital Sound Recording direct to MacBook Pro line input

Using one of the University Recording Studios we set up the Dummy Head with the binaural microphones inside a soundproof room. The microphones were connected directly to the Mac’s line input. To record the audio I used Audacity a free audio editor and digital sound recorder which is available for both Windows, PC and Mac computers. I made one change to the programs preferences changing the input source from internal microphone to line input. As we were using a sound booth I was able to monitor the recording using the Mac’s internal speakers.

I immediately identified a number of limitations to using the sound booth, primarily there was little space to move around the room, which was a necessity for the script and groups overall concept but in counterbalance the audio recordings that were produced were of excellent quality.

[youtube.com/watch?v=4R38s3c9Unw]
Sennheiser ME66 Microphones - Surround Sound Recording Setup

Fig 2.0 Sennheiser ME66 Microphones - Surround Sound Recording Setup

The next step in the audio recording tests was to relocate to one of the Universities Film Studios. With the benefit of the much greater floor space we setup again the dummy head, but in addition we also positioned 4 directional microphones in pairs linked to two Fostek FR-2LE field recorders that is a Digital Audio Recorder. This in effect gave us 4 channels to record on, that is Left Front, Right Front then Left Back and Right Back.

The positioning choice made for these microphones initially seemed obvious with one set in each corner of the space and directed towards the centre aiming as close as possible at the dummy’s head. This however did not provide the sound (Channel) separation we were looking for.

There was considerable crossover between the channels, for this reason we re-positioned the microphones around the dummy head pointing away towards the corners of the studio space. This proved to be a real improvement when considering just channel separation but it created its own problems by physically obstructing access to the dummy head and effecting the binaural recording process.

Sennheiser ME66 Microphones - Surround Sound Recording Setup 2

Fig 3.0 Sennheiser ME66 Microphones - Surround Sound Recording Setup 2

As a final change in the microphone position we tried relocating the microphones to the corners of the studio space, pointing the microphones downward at floor at a 45 degree angle, the microphone stands were extended raising the microphones 3.5 metres above the floor. In effect each microphone was covering a quadrant of the studio floor space. Results proved to be indeterminate using this setup over the original microphone positioning and so in conclusion of these test recordings it was felt that the best results had been obtained with the microphones positioned centrally, around the dummy head and facing outwards to the four corners of the studio space.

Zoom H2 Handy Recorder

Fig 4.0 Zoom H2 Handy Recorder

Based on these tests the best setup for recording surround sound appears to be to have four microphones combined into one recording device centrally located. An example of such a device is the Zoom H2 Handy Recorder.

Microphone Choices

Based on the audio recordings made on the night we came to realise that our choice of microphone which seemed obvious at the time may not have been the correct choice. Our original specification for microphones choice were that in order to get the separation required for the 5.1 Surround Sound audio recording we would require a directional microphone.

Fig 5.0 Polar Pattern Shotgun Microphone

Fig 5.0 Polar Pattern Shotgun Microphone

We used Sennheiser ME66 Microphones which are very sensitive but also very directional and designed to eliminate noises not emanating from the target direction. From the audio recordings we had channel separation but the volume dropped as well as the actor walked into dead spots created by the very directional behaviour of the microphones used. The shot gun microphones we used have a very direction Polar Pattern see Fig 5.0

Fig 6.0 Cardioid Microphone Polar Pattern

Fig 6.0 Cardioid Microphone Polar Pattern

After discussing this with Lecturers we came to realise that a different choice of Microphone may have produced an improved recording. Cardioid microphones seemed to offer the best solution. The shot gun microphones we used have a very direction Polar Pattern see Fig 5.0, as you can see very different to the Cardioid polar pattern (See Fig 6.0 and 6.1 ). All microphones have different characteristics one is called a polar pattern this is the direction and the coverage that the microphone pick up from.

Fig 6.1 Example Cardioid Microphone showing Polar Pattern

Fig 6.1 Example Cardioid Microphone showing Polar Pattern

So a Cardioid microphone (Heart Shaped) will only pick up sound from one direction but has a wider target range. With this microphone we could effectively segment the studio into 4 zones with some overlap so that we still get the channel separation but there would be some overlap so that when the actor walks around the microphones pickup area we would still get the directional change but without such a dramatic volume drop off as they passed between microphone positions.

 

Evaluating the results

The next step will be to evaluate the test recordings that were produced and source another similar location suitable for audio recording, a location which combines the benefits of a sound proof room but with the floor space to be able to setup all the equipment and for the actors to move freely.

An example audio recording from the binaural microphone setup on the night.

Future Cinema – Links to Related Blog Entries

  1. Future Cinema – Project Conclusion
  2. Future Cinema – Sound Effects
  3. Future Cinema – Digital Cinema
  4. Future Cinema – 5.1 Surround Sound
  5. Future Cinema – Binaural Sound – Digital Sound Recording
  6. Future Cinema – 360 Degree Camera Mount
  7. Future Cinema – Learning Agreement (Updated)
  8. Future Cinema – Audio / Film Script 1st Draft
  9. Future Cinema – Binaural Sound Recording
  10. Future Cinema – The Film Pitch
  11. Future Cinema – does it have one?

 

 

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Future Cinema – Binaural Sound Recording

Binaural Sound Recording – Research

Future Cinema – Binaural Sound Recording or 3D Stereo Sound

This our groups idea development for Future Cinema. The studios have already begun in earnest to reintroduce 3D Vision back into Film to give a more immersive experience at the Cinema but what about the sound?

Binaural Dummy Head

Binaural Dummy Head

Our idea is to investigate the technology and research into methods for the introduction of 3D Stereo Sound to Future Cinema productions by using Binaural sound recording techniques.

Binaural sound is produced by using two microphones to record live performances, nothing unusual there, but what is different is that each microphone is attached to opposite sides of a dummy human head. Ideally these microphones will be actually embedded within the ear canal of the dummy’s ears, these ears which should also be a close approximation of the human ear, in order to more closely replicate the sound that the human ear, hears.

This technique could also be applied to one of the problems with the existing sound setup in Cinema. That is when you turn your head the sound direction or source remains the same. So for example, you turn your head to the right your centre sound source is now coming from the right speaker the centre speaker now becomes your left speaker and so basically the films sound sequence has been lost. With Binaural sound this is not the case, regardless of which direction you turn your head the sound source/position does not change. This would be even more useful in a multi-screened environment, although for it to work correctly there would have to be some form of head tracking in-order to switch the sound source being received in the head phones to match the visuals on the appropriate screen.

Binaural Microphone Headset

Binaural Microphone Headset

Another aspect of our idea is that the Binaural recorded sound which is then played back through headphones would be in addition to the existing surround sound system in a Cinema. This would allow the Filmmaker to directly connect with the audience, for example a whispered sound, a personal messages or sound bite could be sent to an individual or to all of the audience but it would appear as if the sound had come directly to them from a person sitting beside them.

The whispered threats from the films serial killer seated right beside you!

The Recording setup

Fostek FR-2LE front view

Fostek FR-2LE front view

The first tests will be conducted using directional condenser microphones positioned so that they are pointing at a subjects head, one each side. The inputs will be connected to a digital recorder for example a Fostek FR-2LE field recorder with the inputs monitored using headphones. I’m hoping we actually get the effect of binaural recording in real time so that we can make adjustments as required.

Binaural Sound Recording test using 2 microphones

Binaural Sound Recording test using 2 microphones

Fostek FR-2LE top view

Fostek FR-2LE top view

Research Sources

Sony – Virtual Phones Website Accessed 07/10/2011 –
http://www.sony.net/Products/vpt/tech/index.html

Wikipedia – Binaural Recording. Website Accessed 07/10/2011 –
http://en.wikipedia.org/wiki/Binaural_recording

The Mind Theatre – Immersive 3D Audio. Website Accessed 07/10/2011 –
http://www.mind-theatre.com/

Future Cinema – Links to Related Blog Entries

  1. Future Cinema – Project Conclusion
  2. Future Cinema – Sound Effects
  3. Future Cinema – Digital Cinema
  4. Future Cinema – 5.1 Surround Sound
  5. Future Cinema – Binaural Sound – Digital Sound Recording
  6. Future Cinema – 360 Degree Camera Mount
  7. Future Cinema – Learning Agreement (Updated)
  8. Future Cinema – Audio / Film Script 1st Draft
  9. Future Cinema – Binaural Sound Recording
  10. Future Cinema – The Film Pitch
  11. Future Cinema – does it have one?

 

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