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Doug Blackburn - The Noisy Audiophile-
Doug Blackburn - The Noisy Audiophile
October 1996
Here we are making this web page that might be read by almost anyone... people who don't know American and Canadian companies make some of the highest quality audio components available anywhere in the world. The average person knows none of the names of these companies. Japanese imports are the only audio electronics many people think exist. In reality, the Japanese companies have only captured the mass market (what other market is there if you are after profits). In high end audio, Japanese electronics are almost invisible. American products rule high end. Canadian products are becoming increasingly familiar. There is a small presence of companies from U.K., Germany, France and even smaller presence from Italy and Nordic countries. Why is high end so different from what the average man-in-the-street thinks audio and audio equipment is all about?
The short answer is: like many things in life, the very best is sought out only by a select audience. The majority goes for whatever is readily available and fits their needs. But some subset of the main group becomes more interested and more involved and seeks out the very best equipment available. It happens in bowling, golf, sailing, wine drinking/collecting, cars, lawn mowers, exercise equipment, barbecue grills, furniture, musical instruments... literally every product or device available on planet earth is available in 'mass market' versions which fit general use/consumption patterns and in hand crafted or precision engineered (or both) versions which meet the requirements of those who appreciate THE BEST.
High end audio is the best of what is available in equipment used to reproduce music, and increasingly video soundtracks, in homes. My personal opinion is that if everyone who bought a mass market 'hi-fi' ever heard a moderate cost 'high end' audio system, there would be a lot fewer mass market products sold and a lot more high end audio products sold.
So what makes a product 'high end'? A complete answer will take YEARS for you to completely absorb and appreciate. Briefly, what 'high end' should mean to you is better sound. Many people also think it means more expensive. Well, there is no denying high end audio can be expensive. But it doesn't have to be. I would be hard pressed to come up with a complete 'high end' audio system (CD, loudspeakers, amplification and wires) under $1,000 (US) which I'd feel comfortable calling 'high end.' At the $1,000 price point, you could put together a NAD CD Player (ca. $300), PSB Alpha loudspeakers (ca. $200) and a Rotel integrated amp (ca. $400). Buy some cost effective interconnects and loudspeaker cable like DH Labs Silver Sonic or one of the 'major brand' entry level lines (Kimber, Cardas or XLO for example). This modest system will sound far superior to an impressive looking department store 'rack system.' The difference in sound quality is very large and will be quite apparent to everyone from a 7 year old Junior to a 70 year old Granny. The old excuse 'you must have golden ears to hear those differences' does not apply. It does not take anything more than normal (or even below normal! really!) human ears to hear differences in high end equipment. Differences between a $1,000 rack system and my $1,000 entry level system are so large anybody can/could hear them easily but few people ever get to hear them side by side. As high end systems go, the PSB/NAD/Rotel system is bare bones 'entry level.' You can progress far beyond this level of sound quality as you select better and better high end equipment.
In previous articles for Soundstage! I described how various companies fit themselves and their equipment into the vast audio marketplace. In this article, I'm going to describe with some detail, what the differences are between a high end product and a mass market or 'mid-fi' product. One thing to keep in mind as you explore 'high end' is that some companies who represent themselves as 'high end' companies and who are presented in magazines as 'high end' companies aren't really meeting the 'letter of the law' in how they design, build and sell their products. They make a big deal of the attention that they pay to some of the important details, and completely ignore other details which are equally important. There are many reasons for this, most are innocent. Attending to ALL the details in any one type of product could take, literally, years. Not something most companies are going to be able to deal with before selling their first products.
Something I find most interesting about high end companies is that they fall into 3 categories (you'll notice this after a few years yourself):
You can find good products from manufacturers in all 3 categories. But the silent guys are often the ones doing the hardest work, laboring over the most details, taking their products the farthest and getting the least recognition for it. I'm finding a disproportion of supremely musical and affordable products coming from these silent types. Honest products with so much attention to detail, meaningful research into what makes their product tick and refinement that you can barely accept that the price is as affordable as it is.
Let's look inside 2 (unnamed) conventional loudspeakers. One loudspeaker will represent a 'true high end' product. The other loudspeaker will be what I call 'pretend high end' - the company may present itself as a high end company but when you look at the techniques, hardware and details, the product is more like a mass market or mid-fi product than 'true high end.' For purposes of this comparison, let's make the loudspeakers around 4 feet tall with full range frequency response, say 30Hz to 20Khz for this example. There are a number of subassemblies involved in making a loudspeaker.
Let's take drivers first. The mass market, mid-fi or 'pretend high end' loudspeaker will use drivers selected as much or more for how much they cost as for how they perform. To keep costs controllable, the frames are stamped from sheet metal. Magnets will be common types sized just barely large enough to do the job. The material of the cone will be economical paper or plastic. The material of the surround (rubber or foam that goes around the outside of the cone) will be durable and attached by some bullet-proof method that will actually reduce the sound quality of the driver because reliability is a higher goal than sound quality. Voice coil gaps will be 'generous' to make assembly easy and to improve reliability. The way the wire in the voice coil is wound on the form will be simple and easy to do, again to keep manufacturing costs low.
A driver in a real high end loudspeaker will either be hand made by the loudspeaker manufacturer, made by a driver manufacturer to the specifications of the loudspeaker manufacturer or bought off the shelf and extensively re-worked by the loudspeaker manufacturer. The frame will be cast aluminum or cast magnesium for high strength, low weight and low resonance. Cone materials will be carefully chosen after 100s or 1000s of hours of study using laboratory testing equipment to observe performance of the cone while playing a variety of music signals and by actual listening tests. Materials can range from plastics with special fillers that improve performance of the cone to fabrics with plastic coatings, metal film, space age materials like kevlar and graphite, or exotic metals which require exotic manufacturing methods. Voice coils are subject to endless research for different winding methods, types of wire used, optimization of the 'gap' which will be small to maximize the effectiveness of the magnet's field. The magnets themselves will tend to be much larger and/or of more exotic magnetic materials. Both increase the magnetic field strength inside the voice coil gap (a very good thing). The 'surround' that attaches the cone to the frame of the loudspeaker will be painstakingly selected from a dizzying array or possible choices, each one slightly changing the final sound of the driver. How the surround material is attached to the cone with be under continual evaluation to find the best possible method from a list that grows longer every year as new adhesives and bonding methods are developed.
The size and shape of the cabinet are selected to match performance characteristics of the drivers and to achieve the desired response of the loudspeaker. The mass market loudspeaker will tend to be more simply constructed. The cabinet material will be selected for low cost with adequate stiffness for the particular loudspeaker design in question. Some resonance tuning will be done, but it will not be more than moderately successful. Care will be taken during the loudspeaker design process to make the cabinet easy to build and for higher volume manufacturers, for machines to do as much of the work as possible. This 'care' will include avoiding costly internal bracing as much as possible and making cabinet shapes as regular as possible. Material selection will be driven by cost making resonance control more difficult than in more robustly designed loudspeakers.
The high end cabinet will use a similar material, called mdf (most people would call it particle board). But mdf comes in a large array of quality levels depending on the size of the wood particles, the quality of adhesives used hold the particles together and how tightly packed the particles are (how dense) which is controlled during manufacture. High end manufacturers will use more expensive types of mdf because of the acoustic properties. In addition, they may use multiple layers of different types of mdf in cabinet manufacture because they can achieve more desirable sonic performance this way. Internal bracing is common and in more expensive loudspeakers it can be amazingly complex and difficult to manufacture. Much less thought is given to low manufacturing cost and a lot of time is spent listening to (or measuring the lab) small differences in material thickness, shape, or dimension. Final cosmetic appearance of the loudspeaker is sometimes not a significant concern. The focus is on sound quality and only sound quality. However, some high end manufacturers also spend a lot of time and effort on the exterior appearance achieving amazing levels of sound quality and beautiful appearance. If you look at a $2,500 loudspeaker and a $3,500 loudspeaker, the only significant difference might be the external appearance. Or the $2,500 loudspeaker might even sound better while the $3,500 loudspeaker looks better. It's YOUR money, you can have whatever you want to pay for.
For example, a small driver is good at reproducing the highest frequencies we can hear, but very very bad at reproducing the lowest frequencies we hear. In fact, if you send low frequencies to a small loudspeaker (call it a tweeter) you can break the tweeter. So you want to send it only frequencies it can handle safely. Same goes for the big drivers (woofers), they don't behave well when they are fed high frequencies. So the crossover separates the high, mid-range and low frequencies into separate 'ranges.' Wires connect these 'ranges' to the correct driver. The crossover usually does its work with 3 kinds of components: resistors; capacitors; inductors. All of these have very large effects on the audio signal itself. The mass market loudspeaker will implement serviceable and reliable devices in the crossover but there will be little attention to identifying and using the best possible parts available for this application.
A high end crossover design will use much more sophisticated resistors. Electrical leads on these resistors will usually be copper whereas common resistors use steel leads (steel can be proven to be detrimental to the audio signal with basic lab equipment). The resistor material itself is also carefully selected and the resistors used are most often 'metal film' types that are much more difficult to manufacture than common resistors. Capacitors are very influential on the audio signal. Construction and materials (type, thickness, geometry) all have a significant effect on the audio signal. Capacitor technology is rapidly evolving and newer types often far surpass the previous generation's 'best sounding' capacitors. High end designers keep up with developments in capacitors and tend to use much newer better sounding types than mass market designs. Inductor technology is just as influential on final quality of the sound of the loudspeaker as capacitors. But inductor technology is not progressing at quite as fast a pace as capacitor development. Still there are improvements in the type of wire used in the inductor, the core materials and geometry of the inductors which can mean noticeable improvements to the sound of the final product.
In addition, the better high end manufacturers spend considerable time in fine tuning the time domain performance of their crossover designs, something totally ignored by virtually every mass market or mid-fi product. This means that the better high end manufacturers analyze the time it takes different frequencies to arrive at the ear of the listener. The goal is to have each driver respond to a sound at the exact same moment. Unfortunately, highs, mids and lows each travel at different speeds through networks like crossovers. The crossover will require tuning to optimize performance of the loudspeaker in the time domain. Of course this tuning will alter the frequency domain performance of the crossover at the same time so the crossover designer must constantly adjust and re-adjust to maintain the optimum combination of time domain and frequency domain performance. You just do not see this level of attention to detail outside of high end.
Even within high end, there are many more loudspeaker manufacturers who ignore time domain performance of their loudspeakers than there are those who practice good time domain performance. Time domain performance of loudspeaker designs has long been known to be an important part of loudspeaker design and sound quality. Believe me, the few manufacturers who DO make loudspeakers with proper time domain performance are not doing it for fun. It's is hard work and expensive work. They would stop doing it immediately if they didn't know it was important.
Some non-high end manufacturers have such little regard for time domain performance of their products that they will intentionally connect tweeter and woofer with the same polarity and the midrange with opposite polarity. This means that when a sound that occurs in the range where the midrange driver and woofer 'overlap' (there is almost always a lot or little overlap in frequency response ranges handled by each driver)... anyway, in that overlap zone, the midrange driver is going backwards at the same time the woofer is moving forwards. There is no way this can sound natural. The original sound was not produced this way. It's bad enough that we have to divide the sound up between 2 drivers, but having the 2 drivers traveling in opposite directions while trying to reproduce the sound is not acceptable, even in otherwise high end loudspeaker designs. Most often this out-of-polarity wiring is done to improve frequency domain performance. But there are other ways to improve frequency domain performance without severely hurting time domain performance. Those other ways just aren't as easy as reversing polarity of the wiring.
The objective of accuracy in time domain performance is to have all portions of a given sound arrive at your ear at the same time. For example: striking a xylophone produces a strong midrange component and some high frequency harmonics. If the mids and highs don't arrive at your ear at the same time, the xylophone will sound less like a real xylophone. The mids will come from a midrange driver and the highs will come from a tweeter. If there is any electronic (crossover) or physical (mounting position within the loudspeaker) time delay in the tweeter compared to the midrange driver (or vice versa) the sound from the 2 drivers will not arrive at your ears at the same time. The best high end loudspeaker designers worry about and fix this. The other manufacturers/designers (high end and non-high end) don't try to fix this and would rather spend time trying to explain away the importance of good time domain performance. Don't believe it.
Posts... I shouldn't have to say this, but speaker wire posts are important. The 2 best types are screw-down terminals (usually you use a Philips screwdriver) or heavy duty 5-way posts with no plastic parts (other than colored washers to indicate + and - terminals). Banana plugs CAN be OK if you use a good quality banana and bad if you use a not-so-good banana. Binding posts with plastic 'nuts' on the posts are not too great. Screws, nails and glue are funny things... high end manufacturers have learned that where you put them and what they are made of affects the sound of the final product. Mass market manufacturers put them wherever it's convenient. High end manufacturers sweat the details of finding the places and materials that both do the job and sound the best. This is a nearly invisible job that is one of the reasons high end products sound better than non-high end products.
Internal wiring...It used to be back before the mid-80s that you could open just about any loudspeaker, get some decent wire and replace whatever was inside the loudspeaker and the loudspeaker would sound better when you got done. When better high end loudspeaker manufacturers got wind of this, they went on a crusade to learn what was really going on inside their loudspeakers. They began using better internal wire first. Today they actually model their crossovers WITH the hookup wire as an integral part of the crossover network. The better high end manufacturers will often have a different type of wire connected between the crossover and each driver. In a loudspeaker with 4 drivers, there can be 4 very different wires used. Each selected because of how it works with the crossover and the driver. Some may be solid core some may be stranded, some may have very thin and hard insulation, others may have more normal insulation and others may have thick foamy/airy insulation. Wire gauge (diameter) is also important. High frequencies seem to like small diameter wires while lower frequencies do better with larger diameter wires. You can imagine the number of variables in this equation. Now throw in the material the wire is made of, usually copper but it can be made 100s of ways that all affect the crystalline structure differently. Now also throw in the type of insulator used on the wire. Each material has different dielectric properties that affect the performance of the wire. This area alone is a huge abyss that many manufacturers refuse to acknowledge. But again, the best of the best can and are doing their best to find the perfect wire for each application.
The result of all this attention to the wiring inside a loudspeaker is that you RARELY hear anyone even attempting to change the wiring in a modern carefully designed high end loudspeaker. If they do change wiring, the result is invariably not as good as the factory job (assuming the factory is one paying attention to this detail!). This raises all kinds of questions about high end loudspeaker designs with external passive crossovers. How in the world, if the wire is an integral part of the crossover/driver network can they allow the end user to change wires and not expect to get some pretty bad results. The loudspeakers with external crossovers that I've seen have always been connected with the same wire to each driver - ignoring that the tweeter, mid and woofer will sound better with 3 purpose-selected wires.
OK, that's just scratching the surface of high end vs. other loudspeaker designs. You probably noted some taking-to-task in there. High end loudspeaker design has a way to go yet before achieving more uniform greatness. My recommendation is to listen around and do pay attention to which designs take the most pains with the most details. If you like 2 loudspeakers, check the time domain performance and go with the one that is doing this correctly. You will find the long term experience of listening to those loudspeakers and living with them will be more rewarding than with the ones that attempt to avoid the inevitable. You also find the loudspeakers with all the details done right will stay in your system longer than the alternative we skipped a couple of the more troublesome details loudspeakers.
Electronic components have other factors that are important. Physical layout, component quality, circuit board material, RCA jacks, attention to vibration tuning and isolation and case/cabinet design & materials are the most common details being sweated. But recently, more manufacturers are examining time domain performance of their creations and fine tuning this with changes to components and layout. They observe the propagation times of various frequencies from inputs to outputs and change things around until the highs and lows travel at very close to identical speed. This is a new-ish development in that a few manufacturers have been doing it for a while (years) but not 'letting the cat out of the bag' to protect, as well as possible, one of the techniques they believe is responsible for their products' high level of performance.
The bottom line is that 'high end' is about high quality sound. The best way to get there is to pursue details. In some cases the details are so numerous as to be irritating. But ignoring them or trying to explain them away doesnmt reduce their importance to the final product.
....Doug Blackburn
