The best way to predict the future is to create it — Dr. Forrest C. Shaklee
Audio can be broadly divided into:
The quality of any recording is affected by
- the position of the recording device,
- its proximity and angle to the source,
- the acoustics of the environment, and
- the characteristics of the sound source and medium.
E.g., if one wants to recreate the experience of listening to a speaker from a certain position in the audience, a recorder (microphone included) could be positioned at that exact location, and might have near-perfect duplication of the human audio system.
The problem is, the positioning of the microphone isn’t very important. One could equally well position the microphone near the source (as stage shows are recorded) and then adjust the characteristics of the audio in the mixing stage.
Both the above techniques will produce two different kinds of audio. Even though the first one seems to follow the human system in spirit, the final audio is interpreted subjectively.
It is not important for a recording device to approximate the position and audio system of the human ear. Therefore, it is unlikely there will be one single microphone or recording system that can fulfill all scenarios, just as the human ear is limited in its scope.
In general terms, a recording system could aim for the following characteristics, if its purpose is to produce ‘uncolored’ audio:
- 20 Hz to 20 KHz Frequency Range
- Straight-line frequency response over the entire range
- 0 dB (20 µPa) to 194 dB
- Infinite signal-to-noise (S/N) ratio
- Controllable ‘directionality’ for on-axis and off-axis recording – to within 1o precision
- Equivalent/Self noise level of 0 db(A)
- 0 dB Gain
- 0% Harmonic Distortion
- Infinite sensitivity (V/Pa)
- 24-bit Bit Depth
- 48 KHz sampling rate
Playback, like recording, is dependent on position – both of the playback speakers as well as the location and orientation of the listener.
For this reason, playback systems have always been tied to acoustic and environment design, to produce a controlled listening space. Practice has shown that it is impossible to limit the number and type of such environments.
If the objective of the recording system can vary between producing ‘uncolored’ or ‘colored’ sound, a playback system is usually designed to reproduce the final mix ‘as-is’. In practice however, this is impossible to achieve, simply because the system and acoustics used to mix the audio will most likely not be used by the end-user. The only situation where a near-perfect balance might be achieved is with stereo headphones.
For general purposes, a good playback system could provide a reproducible immersive audiovisual experience with the following criteria:
- 24-bit Bit Depth and 48 KHz sampling
- Stereo sound (2 channels)
- 20 Hz to 20 KHz Frequency Range
- Perfectly noise-cancelling; and zero ‘bleed’ or signal loss
- 0 dB (20 µPa) to 60 dB fully adjustable volume controls with <1 dB precision
- 3D sound-field corresponding to the human ear
- Design alterable to precisely suit the physicality of the listener’s ears with zero discomfort
- Light-weight and wire-free
The huge advantage of stereo headphones over multi-channel or periphonic speakers is that each listener in the group listens to the same audio. The disadvantage is that each listener is ‘chained’ to a device (seemingly inconvenient, similar to Stereoscopic glasses) but that is the price to pay for a totally immersive experience.
You can either be immersed in one activity, like watching a movie, or talk to your friends and eat popcorn. If a person is inclined to be distracted, there is nothing an immersive technology can do to prevent that. One shouldn’t confuse the inability of an immersive experience to hold the viewer’s attention as its weakness. It isn’t.
That’s the responsibility of the content creater and the viewer. It’s a direct relationship. A perfect immersive experience simply ensures technology gets out of the way.
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