Expanded presentation
Astute Speakers - Inspiration and Story
Introduction
The refreshing opinion of one reviewer, is that when it comes to choosing your system, loudspeakers are the best place to start. He reasons that the acoustics of your room play a pivotal role. Get this right first, and you avoid futile attempts to later correct matters by changing other components.
To address room matching problems we have embodied decades of innovative and award winning design experience in the Astute Loudspeaker.
This is only the start however. The Astute speakers are packed with radical innovative ideas that give them significant advantages. Before unveiling these we need to put them in context and make a few remarks on the subject of innovation.
Great ideas usually take a long time to reach popularity. Understanding why is critical to avoid missing big opportunities. For example, Frank Whittle patented the Jet engine,10 years before the outbreak of World War II. The concept was too large a jump for conventional thinkers in the Ministry of Defence, so the opportunity for massive air superiority was missed. It took many years for this brilliant invention to meet with the success it deserved. The interesting question is, why did it take so long?
1) There is an illusion of "safety" in sticking to well worn paths.
2) There are so many false dawns and crazy ideas that it's only natural to be skeptical.
3) The tendency is to think that the majority must be right.
3) Real innovations are not easily understood and often counter-intuitive - after all, if it's obvious, everyone would be doing it.
4) Entrenched views, based on false assumptions, don't welcome alternatives - to put it mildly.
5) The status quo becomes uncomfortable and feels threatened.
Hi Fi is extremely complex - more so than most people imagine. We are not talking here about hooking a system together and operating it, which is relatively simple. We're talking about selecting a system that's absolutely outstanding in terms of sound quality and performance. Complex decision making is not easy for obvious reasons. You've only got so much time. Only so much energy.
What's more, it can seem impossible to know right from wrong. Everyone is telling you their ideas and products are the best whilst rubbishing those that other people swear by...so how can you possibly know who's telling the truth?
The sheer volume of new products and endless hype only adds to the confusion.
There are ways to cut through the smoke and mirrors, and get to the truth - one is to find companies that repeatedly deliver real results in your own experience.
New concepts need proof and endorsement, especially when they are not readily understood - even by the experts. We do not expect anyone to be persuaded by the thinking behind the Astute - confirmation only happens at audition. However the purpose here is to highlight that this is not just another repackaged speaker, rather it heralds an absolutely unique approach, which if correct will prove more rewarding.
The Comparisons Between Truly Great Sound and Good Sound
It may help to start by asking, what makes a speaker “better” in the first place? We read that most products have "great sound quality", so does your choice really matter? and are there significant differences in what is termed "great sound quality"?
To illustrate the range of difference between truly great sound and "great" sound it is worth looking at a couple of illustrations.
1) The Vienna Opera House is renowned for fantastic acoustics, Audience members travel far and part with a great deal of money to experience concerts at this venue, purely on the strength that it offers a sound quality, unique among other opera houses.
2) Bands or musicians who care about sound quality will only use certain recording studios because they deliver better results than others.
What Is Truly Great Sound Quality?
Hi Fi is very rewarding when you make the right choices. However we hear numerous stories of regret from experienced music lovers over unwise buying decisions. It's important to know the main pitfalls and how to avoid them.
A manufacturer may claim that their product is superior to a competitors product. Often, this is because they focus on selected aspects of the music. For long term satisfaction, every aspect needs to be right, not just most. The priorities may be different from person to person, but all of the following are present in a great system (yet very rarely achieved). We discuss ways to evaluate products on web page "How to Audition" .
Dynamics: The ability to reproduce the full energy of a note without loss of impact. Loss is usually manifested by an artificial softening of bass notes, lack of speed, slightly blurred treble etc. The sound is essentially dull and boring in comparison with a dynamic sound. Dynamics are akin to the acceleration and braking performance of a car. A good speaker will have high dynamics for all frequencies but this is extremely rare. Interestingly the effect of dynamics varies depending on the frequencies produced:
A Dynamic treble has a thrilling effect produced by fast, clean notes etched in space with precision.
A Dynamic mid-band creates fabulous vocal projection, clarity and air.
A Dynamic bass imparts a sense of effortless power and Authority - this can be both relaxing and invigorating.
Timing / musicality: Live acoustic music is coherent and perfectly integrated – Speakers do not always sound this way, for example, the bass may lag behind due to sluggish speed or overhang.
Tonal balance: Too much treble emphasis may produce a lot of impressive detail but soon causes listening fatigue. Conversely a bass oriented sound can initially sound powerfull but will then become heavy and oppressive.
Separation / clarity / definition / transparency: This creates interest as it enables you to “see” into the mix and latch onto each individual strand of the music, whether it be the vocals, drum beat, keyboard etc. The music also has a silent background.
Natural Sound: The ear does not like distortion introduced by resonance, electronics or phase issues.
Freedom from Colouration: Cabinet resonance, cone breakup and ringing are often present in loudspeakers. These are a bit like artificial additives in food and detract from music by causing distraction, usually at a subliminal level but there nonetheless.
Ability to create an “out of the box” 3 dimensional sound image: This is primarily created by high definition and tonal balance. However imaging is also related to cabinet shape, driver dispersion and a reduction of local standing waves around the speaker.
Why A New Approach Was Needed
What exctly enables a loudspeaker to rank in the top 1% in terms of sound quality? We researched this question in great detail before embarking into unchartered waters. The market is extremely crowded when it comes to choosing loudspeakers, with a vast array of ostensibly similar products, most of which have great reviews and similar claims? Why launch yet another? Many experts would say that there are already too many speakers and there is no room for “yet another”, “more of the same”, or “a slightly better box”.
Origin Live agree with this sentiment. We would only release something that addresses unresolved problems.
Achieving higher levels of performance in a loudspeaker, is no easy task from a technical viewpoint. Hearing countless speakers over many years brings a certain respect, that they all have different characteristics.
Interacting with world class Hi Fi designers at the highest reveals a widespread view that very few speakers have the full spectrum of qualities needed to satisfy all requirements. In other words, different speakers do some things brilliantly but others poorly. Discerning listeners want better all round performance from their speakers.
In spite of what may be claimed and what you read, we hear frequently from our clients that many new speakers are not as good as the 20 year old designs in their posession. Are things going backwards? Even modern materials such as Carbon Fibre, Beryllium and Diamond like coatings don't seem to fulfil their potential? There are explanations of course – most of which are unpalatable.
Before examining solutions we need to re-examine how we select equipment in more detail.
Avoiding Poor Choices
Big Brands And The Status Quo
We conducted a demonstration the other day between a £600 phono stage and a £3000 "market reference" phono stage". It was agreed that the £600 phono sounded better by a mile. However because the £600 phono stage is hardly ever reviewed and a virtual unknown, the evidence of the listeners ears was not believed - excuses started to be made such as "it needs more warming up etc etc". The fact that we chose to exhibit with the £600 phono at a show in preference to the £3000 one carried no weight. We relate this story to illustrate the colossal problem of big name reputation and the belief that all reviewers are virtually infallible.
Alongside the gravitational pull of top brand names, you have claims of breakthroughs from many companies. It's easy to be misled by marketing hype and “flavour of the month” ideas reported in the press. We come across clients who relate how they have wasted vast amounts of money on some of these. Sifting out the genuine from the hype is an art in itself but for those who have become cynical we have some sympathy as we have shared the same dissapointment - many times. The thing that keeps us going is that although true breakthroughs are highly unusual, they do exist.
Origin Live have built an enviable reputation for delivering what we claim. We are much more interested in credibility and trustworthiness than a one time sale.
Some big brand names are very good. However there is a myth that larger companies with well earned reputations and large development budgets must inevitably be leaders in the best ideas and designs. Although this rule often applies, it is not always true, Complacency can set in, companies can change ownership, loose their soul, or just head downhill.
There are many stories of how better concepts often come from virtual "unknowns" as demonstrated by the Wright brothers who were unknown and totaly unfunded before their invention of the aeroplane. This was in stark contrast, to massive government funding granted to highly qualified academics working on flight at the same time. Simply throwing money at a challenge is no guarantee of producing results.
Recognising great ideas is not always easy in Hi Fi as the sheer number of new products leads to information overload. When a real breakthrough appears, it appears momentarily by the press and is then quickly forgotten amidst the constant stream of shiny new objects.
The Sacrifice Of Time, Money and Years Of Study
It is almost impossible to realize the sheer time and effort it takes, to improve on tried and tested ways of doing things. A single new idea in isolation is only the start, so many other aspects also need to be right. It's extremely rare for a product like the Astute to appear, with such a catalogue of innovations.
The Long Journey From Concept To Acceptance
Having a successful design is one thing, but to manufacture it with value for money, consistent quality and reliability needs a well run company. Origin Live has an outstanding track record in this respect, which you can read in the “about us “ pages of the web site.
Technical Issues
Using conventional technology, has the attraction of being relatively inexpensive and easy. Minor variations may perform differently or even better than others, but essentially, improvement is limited: The following is a list of aspects to consider before investing in a pair of speakers:
The creation of standing waves inside the speaker cabinet - Oversize waves are created when reflected waves combine with oncoming waves. Box shapes are of course the worst culprits for creating these. The problem is the way in which standing waves intrude on the music. They represent sound not present in the actual recording being added on top of the mix. For those not familiar with the term, this is known as "coloration" and is to be avoided at all costs. It masks low level musical information and causes distraction.
At a more technical level, standing waves influence sound in three ways
i) They emit unwanted noise through the cabinet walls and driver cone
ii) They increase resonance in cabinet walls, which reflects unwanted vibration back into the driver.
iii) They add to intermodular distortion with other sound waves. This last point applies to sound both inside and outside the cabinet. Local standing waves can build up between the walls of the room and cabinet itself.
The Asute's cylindrical cabinet and offset drivers is intended to eliminate significant standing wave issues.
Relatively low efficiency – Experience reviewers have observed that efficient speakers generaly have more powerfull dynamics. This is improtant as previously mentioned in the list of qualities that need to be present in a great system. However there are technical and value for money aspects that are worth highlighting as well. Low efficiency speakers need powerfull amplifiers to drive them properly. Not only does this add expense but more importantly it's a flawed approach for aquiring the best amplification.
High powered amplifiers sound impressive for obvious reasons and are desirable for the vast majority of speakers on the market. However, counter-intuitively, the most cost effective and best sounding amplifiers are often low power designs. These need speakers with above average sensitivity (efficiency) and the right impededance loading. Why class A, zero feedback amplifiers are so good is the subject of another discussion.
Cabinet resonances - When a cabinet vibrates, it produces audible coloration but more importantly it feeds this movement into the speaker driver and upsets the accuracy of sound waves being produced.
Cross-overs in the 2KHz – 5KHz region – This is where the ear is hyper sensitive to phase distortion which affects timing and musicality.
Multiple driver arrays- To increase bass dynamics, many manufacturers include additional drivers which produce exactly the same frequencies as one another. The problem here is the waves from each driver interfere with one another and create distortion.
The adjacent illustration shows a typical floorstander with two woofers operating at 3kHz (roughly to scale). Notice how the radiated lines cross one another. At these points, the wave form doubles in amplitude thus causing distortion.
This interaction of drivers in such close proximity with one another, results in a sound that lacks the clarity of a well designed single woofer speaker. The Astute employs a single large diameter woofer for great dynamics in conjunction with a sub-woofer producing only the very low frequencies. This not only eliminates interference patterns but has additional benefits which are explained later.
Energy Management – super rigid cabinets are intended to reduce resonance and keep sound from exiting through the cabinet walls. Whilst this solution addresses one problem it creates another - In a rigid cabinet the vibrational energy created by driver movement is channelled into the cabinet and then reflected back into the driver. In other words the driver and cone need to be able to conduct their internal resonances permenantly away into the mounting structure. Most structures don't manage this energy absorption successfully and the result is a lack of coherence and timing.
Whilst this may be true to a certain extent, it should be highlighted that a narrow cabinet sacrifices airflow around the driver inside the cabinet by around 30 to 40%. This causes compression effects which are manifested in a congested sound quality, lacking a sense of freedom and timing.
We have listened to this effect and further proof is seen in the design of top high end drive units which often have thin aerodynamically shaped driver baskets to allow cones to “breath”.
The bottom line is that fast, unrestricted airflow behind the speaker cone creates a sound that is open and has a sense of freedom. This important benefit far outweighs any slight improvement of imaging.
Energy reflections caused by rigid structures interacting with the floor. Coupling speakers rigidly to the floor – is incredibly logical and intuitively the “correct” thing to do. The assumption is that providing an immovable reference, enables the driver to function with absolute precision and accuracy.
Oversimplifying complex mechanical issues is a common trap and this is a classic example where more thorough analysis comes to a different conclusion. To save pages of mathematical argument it should suffice to say that Paul Messenger (one of the most experienced speaker reviewers on the planet) has recently concluded that “floating” floorstanding cabinets on specially designed springs proves remarkably beneficial. Another comment worth making is that PA speaker arrays have been suspended on wires for many years and nobody would ever accuse them of lacking bass grunt or power!
Electronic “haze” and “grain” due to inferior cross-over components.
Driver limitations that cause lack of dynamics, speed, timbral accuracy and micro-dynamics due to driver limitations.
Thermal Compression effects from small diameter driver voice coils and low power resistors – causing non-linearity, distortion, and limited dynamics.
This list is far from comprehensive and there are other critical aspects that are addressed later in this article.
INNOVATIVE SOLUTIONS
New Ideas Combined With Tradition
If the secrets of unlocking great sound quality were obvious then owners of mediocre systems would be able to identify problems easily but this is clearly not the case.
The Hi Fi community has some very bright people who discuss the mysteries of Audio with great passion and friendly controversy. We appreciate this and pay tribute that much of our success is due to taking on board suggestions from leading designers and others who have invested countless years of research in pursuit of certain goals.
Keeping an open mind and drawing on different ideas and observations has required a great deal of testing to differentiate the good from the best. We have been lucky many times through discoveries made by chance due to the sheer amount of testing we carry out.
Possesing a machine shop to manufacture everything, speeds up the development process enormously and also enables us to produce much more cost effective designs.
The Astute loudspeakers are revolutionary because of new ideas on controlling energy, drawn from our long experience of leading turntable and tonearm design. They are also revolutionary on the strength of a difficult set of judgement calls, which in combination, deliver a huge leap in performance. Meticulous attention is given to details that many would consider of minor importance.
Let's move on to consider the innovative and specific design philosophy of the Astute.
Energy Management and Vibration
The first radical idea, is to remove the speaker from long reflected energy paths. To produce sound accurately, we all know that conventional wisdom strives to hold the speaker absolutely stationary. This is entirely logical, as ultimate performance depends on the positional accuracy in the motion of a driver. All vibration will of course upset positional accuracy and herein lies the crux of the matter.
You would think intuitively that a heavy, rigid box is the answer – right? This approach is understandable but has a severe problem arising from an oversimplification.
Firstly the "heavy" box flexes microscopically and stores energy that is then released back into the driver.
Secondly, the heavier the box, the longer it takes to release this stored energy.
The next conventional "solution" is to try and mount the cabinet itself as rigidly as possible to the floor or a solid surface via rigid stands.
With conventional bookshelf speakers, the energy of the speaker is transmitted into a stand, which then transmits it to the floor. Some of this energy is then reflected back from the floor, through the stand, only to return once again into the speaker. This long energy path means delayed resonances, causing a smearing effect on the music along with overhung notes, especially in the bass.
In floor-standing speakers the situation is identical, except there is no stand. As mentioned before Max Townsend has launched a special “spring stand” which isolates speakers from the floor. Reviews have endorsed that this approach yields significant improvements.
Springs, spikes and other solutions, all attempt to decouple speakers from the effect of energy reflection but there is a better solutuion.
The Ultimate Solution
Experimentation suggests that "floating" larger speakers is the ultimate solution to delayed energy reflections. We achieve this by hanging the Astute using Dyneema cord - the world's strongest fiber (15 times stronger than steel, weight for weight) .
To illustrate why hanging is superior to other methods it may help to relate the story that initiated this approach. Over 15 years ago, Origin Live developed Loudspeaker Stands that went on to win a group comparison test for 20 different speaker stands in Hi Fi Choice magazine. During the development of these stands, the designer was lifting a speaker between 2 stands for the purpose of comparing them against one another. On asking the listener which stand sounded the best, he answered “neither!” but “the best sound was while the speaker was just held in your hands!” ( this only works with larger speakers). This observation was so unexpected that it met with complete unbelief and needed to be triple checked.
Years passed and Origin Live went on to develop loudspeakers which did exceedingly well in reviews, winning a group comparison test in Hi Fi World. However just another box (albeit a very good one) made little impact on a saturated market dominated by big names. The venture was abandoned with the conclusion to never re-enter the speaker market without a product that was both unique and untouchable for performance.
Since that decision, Origin Live have stumbled across many individual discoveries that are not present in the vast majority of speaker designs. The thought that these discoveries should remain on the shelf and die was intolerable for a variety of reasons. So the decision was made to embark on the 6 year development of the Astute Speakers.
Energy Absorbing Cabinet
The Astute prototypes started off with conventional cabinet materials such as Birch ply. However research tests revealed better ways to achieve the right mix of weight, rigidity and energy absorbtion. We discovered the best results were obtained using different material layers laminated together to form the cabinet walls. This proved highly effective but far from simple to produce.
One of the 4 layers in the cabinet consists of laminated wood fiber as used in many loudspeaker cones. The wood fibers in paper or card consist of microscopic hollow tubes which are rigid, low density and elastic. This makes it a fantastic material in terms of strength and damping. Interestingly this traditional material is still used in driver cone material used in highly respected speakers over £80,000. Proof that this is considered by many speaker manufacturers to have the perfect properties required - outperforming even carbon fibre as a cone material.
Reducing Resonance Through Cabinet Shape
In many box shaped speakers, cabinet vibration manifests itself in the music as a low level thrumming or droning sound. Unwanted panel vibration not only colors the acoustics, but more subtly degrades driver performance by releasing movement into the drive unit.
Tubular structures are renowned for their beneficial structural properties. Unsurprisingly, the tubular construction of the Astute is extremely strong and much less susceptible than normal to cabinet vibration.
Elimination Of Internal and External Standing Waves
Standing waves inside a cabinet cause both internal resonance problems and unwanted sound emitted through the cone. A cylindrical cabinet shape dramatically reduces internal standing waves
You will also notice that the driver is offset from centre on the Astute - this further serves to break up standing waves through the lack of symmetry.
High Dynamics With Minimal Size
As stated in the introduction, speaker size is important for better dynamics. The Astute optimises dynamics with minimal space imposition as illustrated below.
Benefits Of High Dynamics And Minimal Profile:
Uniquely flexible placement – Cabinets hang from Floor Stand Mount, or Wall / Ceiling brackets.
Low space consumption whilst achieving fantastic level of performance.
Ability to suit almost any room due to an adjustable, single source bass. This avoids the “muddy” sound often created by having 2 low frequency speaker drivers interfering with one another. It also avoids the nightmare of trying to position the speakers exactly right with respect to one another along with the ensuing room acoustic issues.
Sound exceptional at low and high volume levels due to outstanding dynamics. Dynamics are also very important for a speaker to sound good wherever you are in your room - i.e at a distance as well as close up. This is because treble “dulls”rapidly over distance unless it has excellent dynamics.
You could easily pay well over 4 times the price for a conventional pair of speakers and still not come close to the performance offered by the Astutes. Although expensive cabinets, exotic materials and components make a significant difference they are no substitute for advanced design philosophy.
Handling Of Frequencies
When we consider the techniques deployed to produce different audio frequencies, there are various schools of thought. The rationale behind these is discussed here to allow an insight into the various merits and challenges entailed.
Conventional design philosophies for handling different frequencies
Some manufacturers promote the concept of a single driver to handle all frequencies. This is initially very attractive and has been tried many times because:
- It avoids problems associated with cross-over phase and distortion.
- It produces a point source.
Alternatively the advantages of using multiple drivers are;
- Less distortion as each driver can produce it's specific frequency range more accurately.
- Much better dynamics
- Greater frequency extension is greater into both the high and low frequency extreemes.
- Reduced cone break up.
- Ability to go much louder.
Problems Created by Conventional Handling of Low Frequencies
Stereo is of no advantage for bass notes below 100Hz as the sound is non-directional - in other words you can't hear where it is coming from.
There are a number of serious problems in the way conventional designs handle low frequency bass notes.
i) Normaly speakers are spaced around 3 meters apart which means that the bass unit(s) in the two speakers interact with one another significantly. In fact it is the worst possible scenario because bass notes have wavelengths in excess of 3meters (10 feet) long ( unlike high frequency notes which can be just a mm or fraction of an inch).
ii) It is very hard to match bass output with different room sizes and types of wall. Solid walls tend to reinforce bass notes. Larger rooms need higher bass output - the list goes on. This makes choosing your speakers a bit like a shot in the dark. How they will sound in your particular room is unpredictable.
iii) The bass extension of smaller speakers is very limited due to small cone size.
iv) The bass quality is often very limited due to the poor dynamics and distortion of smaller drive units.
v) The bass response of reflex loaded cabinets is uneven
vi) Sub-woofers cannot successfully be added because conventional speakers are not designed to merge with them - the low frequencies tend to overlap with one another so much that a "muddy" sound is the usual result.
vii) Most speakers suffer from the vibration produced by bass drivers. The energy pumped into the cabinet massively degrades the performance of the more delicate midrange and tweeter units.
viii) In the case of a 2 way design, reflected bass waves inside the cabinet, directly impact the driver cones, creating mid-band distortion and confusion. This problem inevitably applies to single driver designs as well.
This provokes the question of how such seemingly insoluble issues can be overcome?
Remarks On Potential Solutions:
Sub-woofers are often thought to be an answer but do not slolve all the problems as most conventional speakers roll off bass around 20 to 40 Hz and are not particularly suited for sub woofers. The technical explanation for this is that the main speaker rolls off it's bass so gradualy that the overlap with the sub-woofer is too large and ends up confusing and muddying the sound.
Digital Signal processing (DSP) of the signal to allow bass adjustment is gaining popularity at the moment due to it's theoretical advantages. Colossal sums of money have been sunk into chasing this solution over the years. Without denying that this is a very clever approach which is continuously "re-launched" in some new guise, it never fails to dissapoint.
Many years ago Origin Live understood the potential benefits of this technology, having operated PA systems where it is definitely of value. This led to a great deal of time spent in evaluating leading DSP products along with Class D amplifiers. Our conclusions were that DSP helps speakers that have uneven frequency response and poor cross-overs. However for a well designed speaker it is the purists nightmare. Adding a massive layer of electronics with all the problems of sterility, electonic "grain", and a lack of musicality. In our experience this far outweighs the benefits and is an instance of where “the cure is worse than the disease”.
One of the attractions of DSP is the promise that you can tailor the sound to any room. One problem with tailoring frequency response is getting it right for all positions in the room - For example, in a large room, those sitting close to conventional speakers will want a different treble balance to those sitting further away. DSP cannot address this issue at all, as the real problem is one of dynamics - when you have the treble dynamics of the Astute you are happy wherever you are in the room. The balance is right for those sitting close to the speakers but the perceived drop in treble for those further away is insignificant.
As mentioned previously the Astutes address this issue differently and in a far more comprehensive manner. Such remarks will not sit well with certain ideologies. It is worth adding that this argument is very similar to Vinyl vs CD or Valves vs Solid state.
Reducing Bass Output: In an effort to minimize problems caused by bass notes some manufacturers simply reduce them. This has the immediate effect of cleaning up the sound and increasing clarity. Very impressive initially and a result that deceives many on first audition. However increasing the level of midband and treble results in the sound lacking warmth, depth and weight. Although initially impressive for it's clarity, this ultimately leads to listener fatigue and a sense of unease because the music can never become relaxing and lacks the authority of decent bass.
Advantages of a Single properly Integrated Sub-Woofer
Many people have not got on well with sub-woofers and it is true that they don't work particularly well with most conventional loudspeakers. The problem is that normal speakers have very uneven behaviour in their lower frequencies which stretch right down as far as around 40 Hz. They would need electronic filtering to integrate properly with a sub-woofer and needless to say this is not part of their design as they try and stretch as far down as possible into the lower frequencies.
The Astute speakers have been specifically designed to integrate perfectly with any active sub-woofer. They do this by filtering out the lumpy low end response with a cut off frequency starting at 100 Hz.
Cutting out low frequencies from the main duties of the Astute have tremendous advantages.
i) Amplifier load is significantly reduced allowing for better control of speaker drivers.
ii) Cone misbehaviour from internal bass pressure waves is eliminated.
iii) Distortion is vastly reduced through shorter cone excursion.
Advantages of employing a single sub-woofer are:
i) Low frequencies can be adjusted to suit different room sizes and acoustics.
ii) You can choose from a large range of sub-woofers to meet your budget.
iii) Upgradability - better sub-woofers will significantly improve performance and can be employed at a later date
iv) Bass notes have wavelengths of over 10 feet, depending on the frequency. The sheer size of these notes needs careful consideration. If you have two sources generating low bass, spaced about 10 feet apart, they interact severely with one another. Speakers have at least one bass driver per cabinet. The cabinets normaly have to be spaced about 10 feet apart which causes maximimum bass interference patterns between the drivers.
A single source for bass notes does not have this problem and outperforms two bass drivers spaced apart. You may read articles on the merits of 2 sub-woofers cancelling room nodes. Whilst this is true, and does sometimes achieve clean bass, it has also been observed to dramatically reduce clarity and involvement due to midband and treble degradation. One explanation of this phenomenon is that if you observe large waves cancelling in an ocean storm you see a massive amount of spray and disruption kicked up. Measurements of bass cancellation measure the large waves but don't reveal the side effects.
vi) Sub-woofers can be positioned unobtrusively as the ear cannot detect where sound below 100 Hz is coming from. Note that if you can hear where a sub-woofer is positioned, then it is invariably due to a poor design that is emmiting frequencies above 100Hz.
Avoiding Wave Interference From Multiple Drivers
The Astutes have all the advantages of multi-driver designs but go further by:
Possessing a point source in the form of a co-axial driver. This produces both clarity and great imaging capability.
Aspects of Dynamics
The Astute tweeter has a massive 112dB sensitivity – the equivalent of 16 conventional tweeters. To produce dynamics, a driver surface must be able to accelerate and decelerate with great speed.
Multiple drivers are often used to increase efficiency and dynamics – however this idea has the huge drawback of drivers operating at the same frequency in close proximity, they produce interference wave patterns that both smear the music and cause a loss of imaging – this is the “wall of sound” effect.
Drivers with great dynamics are often avoided by manufacturers because they are costly and present severe challenges of control due to their extreme sensitivity.
How do you perceive the value of a speaker?
Some people perceive the value of a speaker by assessing factors such as the thickness of high gloss lacquer on the cabinets, size, number of drivers, build quality, technical measurements etc. It is no surprise that disappointment often follows as it is design and sound quality that is by far the hardest thing to get right.
A beautiful cabinet can command a high premium but hide a shocking number of unseen flaws that affect performance. Examples of this are multiple drivers with cheap magnet assemblies, brass connecting terminals rather than expensive copper ones, cheap cross-over components and computer generated designs which save a lot of time but are hopelessly unmusical and unable to capture you emotionally.
The real value behind better sound quality is not always easy to appreciate because it lies in the unseen areas of design, experience and costly research – these are often far more expensive than fancy materials and pricey finishes.
Matters are further confused by the fact that one component seems much the same as another. The sheer quality of items is easily overlooked. For example, the tweeter used in the Astute has an extraordinarily high efficiency of 112db – It would take nearly sixteen conventional tweeters to achieve this level of dynamic capability. Seeing 16 tweeters in a cabinet looks impressive and such designs exist. The problem is that although the resulting sound succeeds in being dynamic, it is also horribly confused - one reason why such an approach is avoided by most leading designers.
Additional Features of the Astute
Superb connection integrity
Cable Connectors: The Astutes use a proprietary connection system designed to ensure much higher than normal integrity of signal transmission. High conductivity pure copper as opposed to the relatively poor conduction of brass or copper beryllium / Terillium, commonly found on most speaker connections. Brass is 4 times less conductive than copper and has clearly audible degradation. The copper conductor is further refined in that it consists of stranded copper wire which is again superior to the solid copper conductors found on normal high end binding posts.
Most importantly the clamping forces at the joint are many times higher than normal due to a fine thread clamp and a large diameter nut to enable easy hand tightening. The critical nature of high clamping force in a high vibration environment such as speakers is seldom appreciated. However listening tests convincingly reveal that any reduction in the microscopic “chatter” of a plug results in audible reduction of “graininess” and an increase of purity.
The trend among leading connector manufacturers is to avoid the traditional “chunky” metal binding posts as they produce eddy currents in the excess metal that audibly degrade sound quality. With the usual meticulous attention to detail, the Asute binding posts are custom made from non magnetic Acetal and clamped to the cabinet using vibration damping washers. The results of this design are superior to even the best of other high end copper binding posts.
Easy Amplifier load
As a rule amplifiers don't like working with difficult loads that draw large amounts of current. Inefficient speakers with impedances that drop down to as little as 1 ohm need large, power hungry amps that are extremely expensive to be up to the job. The saying “it's the first watt that's all important” has a great deal of truth.
Low power valve amps producing a mere 3 Watts are considered by some as the pinnacle of purity when it comes to amplification – obviously there are severe volume limitations unless you have hugely efficient horn speakers but the point here is that as a rule, the more power handling is designed into an amp the worse it sounds price for price.
Frequencies below 80Hz cause higher current loads and back emf on amplifiers which has the adverse side effect of draining the power needed to drive the midband and treble effectively. The Astute hanging cabinets are not only easy to drive because they are highly sensitive but also because they do not produce frequencies (below 85Hz).
Meticulous Attention to detail
We are hard to please when it comes to audio and highly sensitive to flawed sound quality. For this reason it took 5 years of research to refine and get everything right. To achieve outstanding performance, it is necessary to examine every detail of the design. This includes exhaustive selection of extremely high-grade drivers, cross-over components and cabinet materials. Advanced energy management techniques are also built into the cabinets to eliminate unwanted resonance. Details that needed particular attention included:
Be-spoke Drivers manufactured to our own custom design.
High accuracy of components, many of which are made in house.
Quality of components.
High Quality Electronic components
Air cored inductors throughout.
High Grade polypropelene capacitors.
Oil Filled Capacitors in the Astute S
High power low inductance resistors
Placement Flexibility
The Astute can be placed almost anywhere and at any height. Partners worried about Hi Fi taking over the house or young children knocking over expensive speakers, love this aspect. Positioning is achieved by:
i) Floorstanding stand - this is movable and allows flexible positioning anywhere on your floor.
ii) Wall Brackets - These allow the speaker to be positioned at any point on your walls.
iii) Ceiling Brackets - Allow the speakers to be hung from the ceiling and away from walls if required
The design of all stands and brackets are such that the speaker can be angled in both horizontal and vertical axes along with height adjustment.
Exquisite Aesthetics and natural Beauty
The deceptively simple aesthetics of the Astute, along with the brackets and stands have been the subject of innumerable hours of design spent by 4 product designers (rather than Hi Fi Audiophiles). This is a form follows function design, and the stands in particular needed a great deal of thought.
The results are stunning, as witnessed at the Gadget show where we noticed many wives dragging their husbands over to the Astute because they actually saw something they liked. Strangely enough, dyed in the wool audio shops are so used to coffin box loudspeakers that they are completely taken aback by the appearance of the Asutes.
Why Dynamics help Clarity
A live un-amplified live brass band will always sound fantastic and natural even though they cannot implement any kind of room correction.
One problem with so many Hi Fi systems is that bass notes quickly swamp and “dull down” the lacklustre dynamics produced by conventional Hi Fi speakers. The dynamics of the Astute speakers are affected 16 times LESS than conventional speakers.
Dynamics are far more important for clarity than is generally realised and they are the only way to achieve great sound in a large room or over distance – the reasons for this are primarily that dynamic waves do not attenuate (dull down) over distance or reflection off side walls to anything like the extent of less dynamic, low energy waves.
Secondly dynamic waves are not so easily “dulled down” by the interference from standing waves in the room. One way of picturing the dulling effect is to compare throwing a pebble into a still lake. The emanating ripples are clear and easy to distinguish – this is like clear sound! If you do the same experiment, but this time throw the pebble off a liner into a storm tossed ocean in the southern ocean you are not going to see clean ripples because they are quickly overwhelmed by the interference of much larger forces at work.
The benefits of dynamic sound are:
There is no direct way to determine the dynamics of a speaker from it's specifications. Things are further confused by the fact that dynamics are rarely consistent across the whole range of frequencies,
Dynamics should not to be confused with dynamic range which simply states the range of frequencies that a speaker produces). Measurements such as sensitivity, maximum SPL and waterfall decay can be indicators of dynamics but are easily mis-interpreted.
More true to life and exciting to listen to.
Great sound is spread over the whole room as opposed to a single “hot spot” between the speakers. The “Hot spot” syndrome is the result of poor dynamics that mean you need to hear maximum direct sound from the speaker and minimize room reflections.
The physics of dynamics is a complex issue that is not easy for most of us to model or picture in our heads. Yes, it is linked to the speed of acceleration of cones but acoustic loading also comes into play ( as in horn speakers and compression drivers). Dynamics are not measured in technical tests and speaker efficiency is not a true or accurate measure of dynamics.
Conclusion
If you love music and want the benefits of awesome sound quality, then please contact us so that we can discuss your requirements.
