Ian F. Hunt

Cinematographer and Filmmaker

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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 – Audio / Film Script 1st Draft

Future Cinema – film script

Film Script – Mental Health by Ian Hunt


Script & Shot List.
Dr Alexsandra

Dr Alexsandra

The story takes place in a Hospital (Mental Institution). The patients eyes are heavily bandaged and he’s strapped to a chair, he can only hear the bustle of a Hospital Ward and passing footsteps walking up and down the corridor, past his door. Night comes and the sounds begin to die away as he starts to drop off to sleep.

Suddenly he’s wide awake, woken from a fitful sleep by the sound of screaming by his Right Ear, the screaming  suddenly cuts off with what sounds like a very final gurgling sound. This is followed by a deeply menacing silence, which is broken only by the sound of a single pair of footsteps walking towards his door, the door opens quietly and someone, a women, wearing high heels comes into the room and walks to the left side of his chair.

 

The sound of excited breathing as a heavily accented female voice whispers closely into his Left Ear

Left Ear: Hello I’m Doctor Alexsandra, How are you feeling – no don’t answer
Sound of the Doctor moving from Left to Right across the back of the patients head (again the sound of heavy breathing – the sound of those high heels)
Right Ear: She says – one of the patients has escaped; when I say escaped the patient could have been released from the secure unit and there been a few accidents in the other Wards – you must of heard the screaming?
Sound of the Doctor moving from Right to Left passing across the front of the patients head (same heavy breathing – and those high heels)
Left Ear: She says – I’m afraid the escaped patient was last seen coming this way and I expect he’ll be here very soon, in fact as soon as he has (She pauses as if in thought – 1 second pause) finished playing with (Doctors voice moves closer) his last victim.

Right Ear: The sound of another scream which again suddenly cuts off
Right Ear: This is followed by the sound of heavy footsteps walking towards the door, but something is wrong, the footsteps are uneven one foot appears to be dragging behind the other.
Left Ear: Ah I hear him coming now (she pauses for 1 second) he’s such a good patient of mine, he’s been so helpful with my little experiments
She Moves from Left to Right
Right Ear: Of course not everyone agrees with my methods – (Doctor moves closer to the ear and whispers) the hospital management were so wrong to criticise my methods, threatened to stop my funding, threatened me with dismissal, but no matter now they are no longer a problem to me if Lawrence has carried out my orders correctly (She laughs).
Right Ear: Sound of the door crashing open, simultaneously followed by the sound of a distant rumble of thunder

(Note this is the first visual of Lawrence standing framed in the doorway, he’s wearing a white coat and holding an enormous kitchen knife in his right hand with the coat sleeve drenched in blood up to the elbow, this is lighted only by the flashes of Lightening (using Lees Strobe))
Right Ear: Good Lawrence is here – now we can begin.
Doctor moves from the Right to Left
Left Ear: Now I am free to continue my medical experiments – the mind so – complex, how the mind copes with pain and the fear of pain, (she pauses 1 second) let us see (pause 1 second) Yes 10 fingers and of course 10 toes.
Doctor moves from Left side to the Right
Right Ear: She says loudly – come in Lawrence don’t just stand in the doorway (Doctor moves closer to the patients ear and whispers) we have work to do (she laughs)
Sound of Lawrence limping into the room, passing in front of the patient, from the Right to the Left
Right Ear: She says – Lawrence that knife is dirty, why don’t you clean it first (Doctor moves closer to the patients ear and whispers) after all we don’t want to give our patient an infection now do we (laughs again)
(Second visual of Lawrence wiping the bloody knife on his left sleeve)
Right Ear: She says – I’d give the knife a sharpen as well while you’re at it Lawrence
Left Ear: Lawrence says – YES Doctor
Left Ear: There is the sound of a steel being rapidly drawn up and down the kitchen knifes edge.

(another visual of Lawrence – but just showing the knife and sparks from the knifes edge – produced either using After Effects in Post Production

or maybe real spark effects produced by using carborundum stone to sharpen the knife)
Right Ear: The doctor says – A small cut from here to here to start maybe (voice starts very close to Right Ear then moves around the neckline and ends very close to the patients Left Ear.)
Left Ear: No – (pause 1 second as if in thought) – that would be too quick hmm, I’ve changed my mind – (she moves to Right Side)
Right Ear: Lawrence let us begin (pause 1 second) Lawrence lets start with one of the little fingers shall we (she laughs)
Left Ear: Lawrence says ‘YES Doctor’ followed by the sound of the knife falling, cutting through to the arm of the chair.
Central – The sound of the patient screaming

THE END

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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