AirsoundTM
There are 3 reasons for listening to an Airsound system:
- It has a wide listening area that will cover most rooms – You can cook, iron, do DIY, pace around your room, or chat to friends, and still appreciate the music quality.
- The sound is very clear and the spacial element means that you can hear individual voices and instruments with much more clarity and definition.
- There is only one source, the systems are therefore built more efficiently for the sound you receive, so you get excellent value for money
Some technical details
The AirsoundTM gives the impression of depth and 'space', and a realistic 'picture' of the sound as it was recorded. This new patented technology uses 21st century advances in acoustic design, yet retains economy of manufacture.
AirsoundTM electronically separates the spatial field information from the original 2-channel audio signal, it then drives the 'main information' through a high quality loudspeaker array, and modifies the resultant audio pressure waves with a second loudspeaker within the same box, driven from the 'spatial field information' channel and directs it in a special way, to modify the sound information around the loudspeaker unit. The result is that the ears hear sufficient audio clues to convince the listener of a panorama of sound rather than a single source. The illusion is solid and pervasive, and includes a considerable sense of depth; one that is very much greater than can be achieved with dual loudspeakers in a conventional manner.
Details about the development
The History
Back in 1931, the scientist and inventor Alan Blumlein described a method of recording and reproducing 'stereophonic' sound: His arguments and theories involved the idea that as we have two ears, then the ability to recognise where a sound is coming from is to do with how the sound reaches the ears; that if one side is louder than the other, then the sound is obviously located on the loud side.
That sounded logical, but even in 1931 Blumlein was not convinced, and he recognised that there was a lot more to 'stereo' listening than the positioning of the sound. He went on to describe in theory how it might be possible to record and reproduce 'spatial' sound using a principle called 'sum and difference'. This involved using an omni-directional microphone to record the 'information', and a figure-8 response (or 'dipole') microphone set across the 'field of sound' to record the spatial information. By adding and subtracting the 'omni' or 'sum' with the figure-8 or 'difference' signal, it's possible to arrive at a conventional 'left' and 'right' audio signal; although, there are significant faults in the argument that creates a stereo signal from an 'M/S' signal.
In spite of the inaccuracies, the M/S system can be used as the basis of reproducing sounds with space; the M signal represents the majority of the 'content' while the S contains all the spatial information.
Recently, television receiver manufacturers and film sound editors have recognised that it's possible to 'throw' sound outside the confines of a 'stereo pair' of loudspeakers by manipulating the spatial content of the stereo signal.
The First Principle
In sound reproduction this M/S recording system can easily be reversed such that a sum of left and right information from the stereo pair can be reproduced by a normal monopole loudspeaker and a difference (left minus right) signal may be reproduced through a coincident dipole loudspeaker across the field of sound. By doing that, the combination effect produces a representative image; however, the errors in what is really L and really R combine to produce a muddled and less than satisfactory spatial image.
The Second Principle
As well as the scientific principle of M/S (sum and difference) recording and reproduction, a further scientific principle is relevant and important to the 'field of sound' loudspeaker, this is the 'surface effect' of acoustic propagation adjacent to a flat surface.
When a sound is reproduced in close proximity to a flat surface, being a surface that is of greater linear dimension than the wavelength of the most significant frequencies within the sound, then the reflections from the surface have the effect of reinforcing the wave motions across the surface such that the volume of the sound is maintained at a distance from the source loudspeaker.
This effect is easily understood by thinking of being on the banks of a lake when the air is quiet and still; under these conditions it's easy to hear quiet conversations right across the water, this is an example of the 'surface effect'.
The AirsoundTM Combination
AirsoundTM is the combination of electronic processing, the application of the M/S principle combined with the surface effect principle, and the detail design of the loudspeaker arrangements. The system is protected by patent.
The AirsoundTM loudspeaker system is a significant improvement over conventional loudspeakers in three respects:
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In a domestic environment, it is no longer necessary to place a pair of loudspeakers accurately to optimise acoustic performance.
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The depth/width effect can be appreciated over a very wide listening area as opposed to the conventional arrangement where deviation from a fixed listening position at the apex of an equilateral triangle made by the pair of loudspeakers and the listener degrades the stereophonic effect.
- By virtue of the single sound source, the audio path lengths to the ears of the listener are proportionally the same irrespective of the position of the listener with respect to the loudspeaker unit. This provides improved clarity of sound by the elimination of path length phase distortion common with all dual loudspeaker systems.
