System simplicity. 2001/12

I have noticed an interesting syndrome about the best sounding audio systems that I have heard that correlates with the best sounding recordings that I have heard: System Simplicity. The least amount of 'stuff' needed to reproduce music with your home stereo will probably result in the best sound overall.
 What does System Simplicity mean exactly? Let us work backwards from the speakers. Speakers with fewer drivers seem to have a more coherent and accurate sound than those with many drivers. Of course it is possible to build a really bad sounding speaker with 2 drivers (Woofer and tweeter) but I am assuming equal design knowledge and execution. Some examples of overly complex speaker systems are those designs that use things like super-tweeters, rear firing tweeters, subwoofers, multiple cabinets and speakers that require two amplifiers per channel (bi-amping). The more the musical spectrum is divided up across multiple drivers the less chance there is of the final sound coalescing into a single sound that best represents the integrity of the source. The ideal speaker system is one that could be called a 'point source', where, ideally, all sound would radiate from an infinitely small single point in space. While this is impossible in practice, it is quite clear that a huge, five driver speaker cabinet requiring multiple amps per channel is the antithesis of this concept. Simple speakers do not require complex crossovers (the element, usually inside the speaker, that has the job of taking all the frequencies coming from the speaker wire and dividing them up and sending them to the correct drivers). Crossovers are not without losses. They use up amplifier power, decrease the efficiency of the speaker, and create phase distortions (sound arriving at different times). The most simple two-way speakers might only have a capacitor on the tweeter to keep the lower frequencies out while the most complex four- and five-way (or more) speakers will have crossovers so full of components that it is remarkable that any sound arrives at the driver side. Evidence of the inherent goodness of simplicity in speaker design is just how good basic two-way speakers can sound. There is a musical correctness about some of these basic speaker systems that is counter intuitive to their price. No, they are not perfect, but I have been more often impressed and pleasantly surprised by the competence of some sub $500 speakers than I have been with speakers costing over $3,000. A simple speaker will generally not need a complex amplifier to drive it, which brings us to the previous step in reproduction.

Amplifiers, whether they are integrated, power amplifier, or pre-amplifier, also benefit from the concept of simplicity. An amplifier can actually be thought of as a series of amplification devices. Each device boosts the signal a little more. The more power you need, the more output devices you will have. The more output devices you have, the greater the complexity of the amplifier. Complex and inefficient speaker designs require greater and greater amounts of amplification;  simpler designs need less. You can see how complexity in one area creates a necessary complexity in another area, the end result getting further and further away from the purity of simplicity. In fact, most amplifier designers would probably tell you (if they were to be candid about the subject) that their lower powered amps intrinsically sound better than their high powered amps. True, they may not drive an inefficient speaker to an acceptable loudness and this would tend to suggest that, in this situation, one needs the high power in order to get good sound from that particular speaker. However, the end result will never be as good as using a speaker that needs less power to start with. In other words, complex and inefficient speakers that require large amounts of amplification greatly reduce the chance of fidelity.

Ironically, making a system simple and state of the art can require some superb design and execution as well as very high quality parts, which usually results in expensive equipment. Certainly not all expensive audio equipment is simple, or good, for that matter. In fact, I would say that most of the really expensive audio equipment is quite bad. If you were to simply reach into a pool of expensive audio equipment and a pool of budget, but well-conceived (as opposed to just cheap junk), audio equipment and randomly assemble a system, there is a very good chance that the latter will be a much more honest sounding system. Complex circuit designs are complex because they are generally trying to fix a problem that exists because of the use of cheap parts and poor engineering. For example: most amplifiers use something called 'negative feedback'. This is a circuit design that takes a sample of the output and compares it to the input. The circuit makes running adjustments to get the two sides to match each other as closely as possible. Seems like a good idea. The main reason for using such a design is that it is cheaper to implement than to start by building an excellent amplifier that doesn't need such a fix. Why is this important? Negative feedback designs show very little measured distortion on paper. This is a good thing from a marketing standpoint. However, the very nature of this design is flawed simply because it is not possible to adjust the input stage of something fast enough by reading the output of that same thing. Unfortunately, acoustic instrument fidelity is more complex than simply having a low total harmonic distortion figure. Kind of like trying to lift yourself in your own chair. This kind of design compromise is acceptable in a budget product where the entire unit might have to sell for $400, but it is not an acceptable circuit design if the product is going to sell for $4,000. Why the former and not the latter? Good power supplies can be very expensive and it is not reasonable to expect a product designed to sell for $400 to be as good as one that sells for $4,000 and may contain one or more $400 power supplies. It is, however, not reasonable for the $4,000 product to have the same compromised circuit design of the $400 product, but have a $400 faceplate. All too often this is what happens.

Another example: Balanced circuits. In a regular circuit connection (RCA-style pins and plugs from your CD player, VCR, etc.) the signal travels on the pin and the ground is the sleeve. In a balanced connector (an XLR connector, which has 3 pin locking male and female connectors), the signal has a pin, the ground has its own pin, and the other pin is used for the inverse of the signal pin. Noise entering a cable will probably not affect both signals (+ and -) equally. The equipment receiving the signal can electrically add the + and - and throw away any signal left (a perfect noise-free system would allow the + and - to cancel each other out exactly, leaving no noise to throw out). This is useful if you are running lots (hundreds of feet) of mic cables or speaker cables, all bunched together with other cables. The main advantage of balanced circuits is their resistance to noise, thus balanced circuit design is mostly used for professional audio. The downside to this circuit design is its complexity. By its very nature it must have twice the number of output stages in each piece of equipment (plus added transformers) to accommodate the second signal. For almost all home audio applications, this kind of circuit is of little value simply because the home environment and cable lengths do not pose any real threat to circuit noise. So why are balanced circuits used in home audio? Marketing. Having a 'professional' connection method 'sounds' good. Having balanced circuits 'sounds' good. Having bigger connectors with locking attachments 'sounds good'. Too bad it all only 'sounds' good on paper. Ironically, there  are some engineers at the most esoteric end of recording who have eschewed the professional balanced circuitry in favor of the consumer single-ended design simply because it sounds better and, in many recording instances, noise is not a problem that must be eradicated. This is what happens when you get people who actually listen to the end result as opposed to those who simply buy into the marketing of the product.

This complexity of circuits is exactly why I do not have high hopes that surround sound will eclipse stereo (and, believe it or not, there are users out there who consider stereo already inherently worse than mono) in terms of fidelity. I know all about the perceived locations of sound and all about the weakness of the two channel format when it comes to re-creating the many aural cues that a 3-dimensional environment has. However, it may simply be a case that the cure for re-creating the 'space' of an environment is, by its very nature, at odds with re-creating the tone, timbre and resolution of the instruments in that environment. In order to have 5, 7 or 9 channels of reproduction, it is necessary to have a healthy dose of complex computing and circuit topology in your amplification. This is simply at odds with the purity of simplicity. This may be the way to re-create special effects, but that is not my concern when it comes to re-creating an acoustic performance.

In another ironic twist, it is interesting that one of the purported benefits of surround sound for music is the re-creation of an acoustic event in a real space, and yet almost nobody actually records an event in that way. The concept of panned mono has not proved to be a better solution to real stereo and I see no reason why we should ever expect panned mono surround sound to be any better at it. (For more about panned mono, please see "Sonics" 5/98, p.35)

Our more well-heeled audio listeners or observers may have had the interesting experience of hearing a small, inexpensive system that was just a whole lot of fun to listen to. Those same listeners may have also had the experience of sitting down in front of a house priced stereo system and wondering what all the fuss was about. The first system has the basic concept right, but is held back by budget; the second system has the budget, but missed the basic concept of fidelity of reproduction.

If you ever get a chance to hear a high end audio system designed around this concept of simplicity, you should avail yourself of it. It will change the way you view home audio reproduction forever.

© Cadence Magazine 2001

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