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"In 1971, Ian Paisley first set out to build the absolute best speaker he possibly could. At the time, it was generally unknown what characteristics people preferred in a speaker and produced the most lifelike effect. Frequency response was the most quantifiable, and therefore most trusted, standard of measurement so this seemed a likely starting place for his design. He achieved this with a model that measured flat from30Hz to 20Khz, varying by only +-1/4 db. To his great suprise it sounded terrible!
The Start of Acoustic Research
Ian learned the hard way that engineering a loudspeaker involved substantially more than merely aiming for a flat response. Although this characteristic is undoubtedly vital to accurate, natural music reproduction, it alone is not enough to guarantee good sound. Shortly after Ian’s initial experiments with his own speakers, he joined a group of researchers whose goal was to determine the distinguishing characteristics that people consider important when choosing a speaker. This revolutionary study was conducted at the National Research Council, popularly known as the NRC.
Double blind listening trials tested more than 330 speaker designs with 2000 listeners from a broad demographic spectrum. The extraordinary results of this research were an enormous surprise not only to the industry but also to “audio experts” around the world.
It had always been assumed that listeners had many different preferences for sound but the startling results of the testing showed that 97% of the trial participants consistently selected the performance of a small group of similar sounding speakers as their top choices. What this data revealed was that anyone, regardless of their “audio” inclination and experience, can choose a superior speaker, and secondly, that speaker preference does not depend upon musical tastes.
Based on the results of the NRC’s research, Mirage engineers determined that there were three characteristics common to the speakers that consistently achieved high scores in the listening trials. These characteristics were low distortion, wide bandwidth, and flat response both on and off axis.
Continued Research
Most of these characteristics, such as low distortion and wide bandwidth, can be considered simple common sense. Everyone would want a speaker capable of playing both the highest and lowest frequencies (wide bandwidth), and do this clearly (low distortion). Flat response on and off axis, however, was a bit of a surprise.
Speaker designers of the time went to great lengths to convey the importance of placement of the speaker and listening area. This was done to maximize the listening experience by locking the listener into what was referred to as the “sweet spot”, the one restricted area where music reproduction was at its finest. This effect created a soundstage located between the two speakers. Research showed that the average listener preferred a more realistic soundstage, one that could spread far beyond the speakers, even the room boundaries, to create a musical reproduction truer to the original recording.
Understanding How We Hear
Research proved that in a live musical environment, approximately 30% of what we hear is direct sound while 70% is reflected from walls, ceilings and floors and only reaches our ears a few milliseconds after the direct sound. The human brain uses direct sound for identification and to calculate location, but uses reflected sound to determine musicality and spaciousness, as well as direction. If this reflected sound arrives at our ears with inadequate high frequency content then the reproduced music is identified by the brain as artificial. Ian recognized that a speaker capable of recreating the correct direct to reflected ratio would therefore reproduce sound with far greater realism and faithfulness to the original instrument and environment.
Eventually Ian’s tireless research into acoustics and how we perceive sound allowed him to understand how the brain processes this information. A new set of tests began. At this stage he had already created many speakers that were establishing Mirage as a force in the industry. But his search for the most realistic sound was far from over. Armed with the knowledge that the 30% direct to 70% reflected ratio was vital to a realistic music reproduction, he set out to test exactly how the speakers of the day measured.
Examining Conventional Speakers
Ian’s data showed that a conventional speaker had opposite ratios of direct to reflected sound, or 70% direct and 30% reflected. The realization struck him that such a speaker could not mimic a live performance and conventional designs would not suffice.
A conventional speaker has drivers mounted in the front of the cabinet. If it is capable of creating wide dispersion, it can create a large soundstage but not convince the brain that it is, in fact, listening to a live band as opposed to a recording. This is because most of the sound is coming straight from the drivers, directly to the listener, with very limited reflected sound. He reasoned that rear mounted drivers in a cabinet should boost the reflected sound and much more accurately recreate a realistic effect.
At this stage of speaker evolution a technology existed called dipolar using front and rear drivers though it did not provide the characteristics that Ian sought. Dipole front and rear drivers radiate out of phase, which means that when the front driver ‘pushes” air outwards, the rear driver “pulls” inwards. The drivers are always moving in the same direction, canceling a lot of the speaker’s energy, and drastically reducing its off-axis dispersion. The dispersion pattern of a dipole is often referred to as a “figure 8” pattern, as it resembles two teardrop shapes emanating from the cabinet.
Ian experimented with speakers in a bipolar configuration, where both front and rear drivers operated in phase with each other. The result was a much wider dispersion than a dipolar configuration and a large sound stage that created an unbelieveable convicing live listening experience. Ian's first speaker to contain this technology was the Mirage M-1, which went on to win speaker of the decade by 'The Absolute Sound'. Later, Mirage later coined this technology as OMNIPOLAR, which better explained the true radiation pattern of Ian's invention.
av Mayro_inaktiv » 2005-08-29 18:25 
Det är ju humor på högsta nivå! 
Men jag tycker du borde ha bättre högtalare, jag tror du skulle tröttna på dessa då du är van med "värre".
