Eardrums, speakers, rights & wrongs.EDITED VERSION!
"Unique" has almost become a tired old cliché in the world of high end AV. Every man and his passive crossover are claiming "unique this" and "unique that". The sad truth is that 99.9999 (yes six nines!) of all the loudspeakers in the world are all using exactly the same, fatally flawed, 100 year old technology that does not work! Pistonic motion (cones, domes, ribbons and panels, yes including Quads!) and passive crossovers (inductors, capacitors and resistors) were first used in audio in the early 1900's! They didn’t work then and they still don’t work today, here are the two reasons why.
Timing, Timing and Timing & Speed, Speed and Speed . Please be patient, read on and allow me to explain this radical but true statement. OK, hold on to your preconceptions cause this is really going to put the hungry cat among the fat pigeons!
Timing first;
The human (and all the other land based mammals) ear does not care what a sound is, what a sound sounds like or if a sound is pleasant or unpleasant. All that matters is where a sound is coming from in three dimensional space. All mammals ear brain mechanisms were developed to locate prey or flee from predators. In mammals the primary trigger for the fight or flight response is aural. When our primate ancestors detected a noise they instantly bolted in the opposite direction, away from the source of the noise. They may have been 10 meters into their flight response before they correctly identified the sound and realised it was as a false alarm… like a falling coconut. Or they may have identified a snapping twig as a predator was about to strike, then they looked back and thought that was close!
Natural selection ensured the survival of the creatures with the most accurate spacial location hearing mechanism not the most accurate tonal identification mechanism. So how does this well documented and accepted science & biology affect you and me in today's audio world?
To answer that we must first take a brief look at the mechanics of our ears and how they work, how they don't work and how fast they work.
Fact, our ears do not use pistonic motion!
Our ears use a rippling (or bending wave) principle to decode sounds. The outer ear channels sound waves (a series of compression and rarefactions in the air) down the ear canal onto the centre of the ear drum (imagine dropping a small pebble into the centre of a calm pool of water) which then ripples in response to this sound energy hitting its centre. Various tissues & tiny hairs and nerves located all around the edges of the ear drum (imagine how a spider uses its legs to detect the movement of struggling prey in its web) convert this movement, Kinetic energy, into electrical energy, and these impulses are then sent to the brain for decoding.
Now speed.
The ear drums response time is critical. How quickly the ear drum starts and stops the rippling motion determines the accuracy and effectiveness of our ears. Mother nature addressed this mechanical limitation by evolving the fastest possible energy conversion system, the rippling or bending wave ear drum motion. Pistonic motion is far too slow. The reason the ear drum does not work like a cone loudspeaker driver (a mass on the end of a spring) is because it would be in constant oscillation as it wobbles in and out never having enough time to settle back to its neutral or starting point. This would send a constant stream of "ghost echoes" to our brains which would be impossible to decode quickly and accurately.
Our ears are incredibly sensitive and specialised devices which are designed to detect where sounds are located (spacial information) in a fraction of the time it takes to identify what a sound is (tonal information).
The point to note here is that our hearing mechanism is ultra sensitive to time domain distortions. So the fundamental prerequisite in order for any loudspeaker to reproduce life like accurate sound is that its response time (speed) has to match or exceed that of the human ear.
Someone with average hearing can detect time domain errors down to an incredible 25uS (25, one millionth's of a second)or even less if your hearing is very good. The very best ribbon drivers covering 2KHz & above settle in an average of 100uS, the best dome tweeters have a settling time of between 140uS and 180uS, ultra fast midrange units need over 450uS to settle in the 500Hz to 2KHz band and a typical high end 12" bass driver can continue to oscillate and resonate for nearly a second after the initial musical note or impulse stops.
There is a driver which covers the entire 300Hz to 30 KHz band with a blindingly fast rise time of 13uS and does so without any of the ghost echoes and distortions caused by sluggish pistonic drivers slow settling times. It covers 90% of the audible frequency range with both rise and settling times that average over twenty five times faster than the very best pistonic drivers. Even more startling is the fact that this driver is so fast, the 13uS rise time is undetectable by the human ear, even a very good one! How is this possible I hear the sceptical voice cry?!
By refined the worlds only true rippling or bending wave loudspeaker system incorporating linear phase (time and phase coherent) digital crossovers and a genuinely unique cabinet material.
All full range loudspeaker systems are a combination of three equally important components; the driver, the cabinet and the crossover. In a world obsessed with measurements and statistics its easy to forget that it is more important how music sounds than how it measures.
A loudspeaker cabinet is not a passive box. Regardless of its material & construction techniques, a loudspeaker cabinet must be viewed as an active component which is equally important to the overall sound as the driver and crossover. The cabinet is an active energy conversion system, its job is to contain and convert energy, it must deal with the sonic back wave produced by the drivers it houses. Remember that the back wave disappearing into the cabinet is just as loud as the sound flowing into your room!
Creative engineering solutions can convert the kinetic (sound waves) energy of the back wave into heat energy by utilising proprietary viscoelastic materials and techniques.
MDF, plywood, hard wood, phenolic resin or plastic simply can not approach the energy conversion characteristics of this new unique 16 layer Self Damping Compound (SDC).
In acoustics the most important law of physics is, "for every action there is an equal and opposite reaction", so for all the musical sound you hear filling your listening room there is exactly the same amount of sound energy bouncing around inside the speaker cabinet! How can you convert this sound into heat before it bounces back out through the driver diaphragm out of phase!?
The only answer is…. ?
