In a future perfect world, the crossover network would be as redundant as a starting handle on a car. No one has yet invented one drive unit that can cover the range of human hearing; therefore, to achieve this, the load has to be shared by two, and sometimes three, specialised speakers.
In a conventional loudspeaker, the crossover network is a vital component that filters out inappropriate frequencies for each driver so they operate within their performance envelope. It then passes the result to the cones and domes of a speaker, making the sounds produced go as high and as low as possible. This reproduces as much of the recording’s sonic range as the technology allows.
Plot each driver’s output on a graph and everything looks great. Each part of a crossover’s output creates a curve which rises and falls, covering its part of the audio spectrum; the tops of each curve join together to look fairly flat, becoming what you mostly hear. This has been the status quo for over fifty years.
The issue is that the curves that appear to join together have nothing at all to do with the accurate reproduction of music, as they are plotting the output of a laboratory-sourced test signal.
Because of how crossover components react to more complex signals like music, the more complicated the crossover, the less the structure of the original signal stays intact. What we mean by that is that it stays in the same order. When the signal arrives from an amplifier, it is in pretty good shape. So unless a first-order crossover (a roll-off of 6 dB per octave) is used, the following irreversible damage occurs.
Changes in transients, amplitude time and phase. Which simply put means that what comes out of your amplifier does not come out of your speakers in the same order, form, or even volume.
If all a crossover had to do was play back test tones, all would be well. Real music, however, has rhythm, harmonic structure, and dynamics. It lives and breathes like a living creature and, like a living creature, has a complex structure.
We can all recognise the voice of Sinatra, Ed Sheeran, and the sound of The Berlin Philharmonic, even the newsreader on the radio… but they do not sound LIVE.
We are so used to our music being manipulated, we think it sounds normal. Don’t even mention MP3.
If we could SEE what was happening, we would get it immediately. Our ears, however, work in a different way.
Ironically, if the images sent to a TV or projector had to go through the equivalent of even some of the best loudspeaker crossovers, nobody would ever buy them as the images would be so distorted in shape, colour, and definition.
Just like listening to music encoded with low bit rate MP3, with most crossovers, our subconscious brain is working hard with our own built-in error correction to convince us all is well.
Below is a visual attempt to convey what the brain has to do with sound after it leaves most crossovers.
Jsut lkie we do not hvae to raed evrey leettr as the iporatnmt tinhg is the fisrt and lsat leettr and wtih taht trhee is sicienufft srtcutre for the brian to mkae secne of it.
With most crossovers, frequencies are passed at inconsistent times between each drive unit causing errors in leading edge information. These are the VITAL spatial cues. In addition, transients, image scale, image placement, volume and timbre are changed.
Like the example above many of the subconscious aural cues have been compromised and now the brain has to work hard.
ALL THIS DAMAGE TO THE SIGNAL DIMINISHES THE BELIEVABILITY OF THE PERFORMANCE.
The concept of stereo works well and it will work beautifully and sound real if the key component what makes it work arrive at your ears at the right time and in the condition they left the amplifier.
To explain this further.. Taking the above jumbled paragraph.
A second order crossover (A roll off of 12dB per Octave) will flip half of the letters upside down while a fourth order crossover (A roll off of 24dB per octave) would not reverse any letters or change their order …but instead duplicate the first and last letter of each word e.g. ffirstt aandd llastt lletterr ooff eeachh wwordd (as each driver is a full cycle behind the next).
We want to state that although we are pointing out what we perceive as shortcomings, some great speakers have been, and are being, designed and built using this approach with care and pride. They are then purchased, owned, and loved with equal care and pride. All speakers are, for their designer, a series of compromises, choices, and priorities which evolve their own solutions. There is nothing wrong with that. The world’s speaker industry has done it this way for over sixty years, and there are literally hundreds of millions of speakers out there bringing joy and pleasure to billions of people.
Having been building and improving existing crossovers for nearly forty years, we speak from experience.
Other options that the speaker designer has to consider include the choice of crossover components, whether to mount them on a circuit board or hard-wire them, or indeed whether to make the crossover external to the main speaker enclosure or go active. In addition to the changes mentioned above, vibration, field effects, and even the choice of cables can add damage to the signal in the form of distortion. So, as mentioned at the beginning of this piece, in an ideal world, a crossover would not be needed.
Nothing has changed as in the 1957 edition of the book Hi-Fi for Pleasure by Burnett James he writes:
“ There is a school of thought among loudspeaker designers which holds that crossovers ought to be abolished altogether maintaining that they introduce insoluble problems of their own and the impossibility of completely eliminating an internal change between the different drive units.”
….and went on to say “Second order and above crossovers destroy harmonic integrity and damage magnitude response”.
At William Eikos, our choices, priorities and technology are different.
The Aurigen speaker has only one crossover component (first order) gently shaping the very lowest notes of the music being reproduced. Everything else is wired directly to your amplifier. So what leaves the amplifier stays intact through to you, with everything in the right order and at the right time.
Your brain can subconsciously relax, emotionally engage, and make much more sense of the music without having to work hard, as everything sounds natural, easy to listen to, and real.
We would like to state that we are not alone in our opinions on crossovers there are a number of recognised speaker manufacturers who hold similar views.
At William Eikos we like to explain features of our products that solve issues that have dogged conventional loudspeakers for decades. These explanations can be technical and are perhaps not for everyone, but if you decide to read on, we hope they will enlighten you as to why our products are special and represent a major technical leap forward in bringing you closer to your music and therefore aid you in making an informed decision.
There are four papers in our series:
Please feel free to contact us if you require any further information.
I have been listening to interconnects for years and thought I had the best but this has beaten everything I have.
David Denyer PR - UK Hi-Fi Opinion Leader Tweet