Principals of Audio: Introduction


A practical guide to system building

Introduction:

The Lilliputian realm of audiophilia is united by the quest for fidelity, yet riven by innumerable conflicts over issues that appear trivial – even ludicrous – to outsiders. Furious online debate between Big-endian and Little-endian factions have flamed into real violence – although commonly the physical incarnation of a hi-fi tribesman is a gentler entity than his keyboard-warrior avatar suggests. The demographic is petulant old men, so par for the course. At shows, meets and bake-offs, alcoholically relaxed, softened by the camaraderie of the like-minded, misty-eyed under the influence of a cherished track . . . genial audiophiles appear, belly first. It’s all very Gaelic.

The hi-fi trade is part art, part science, part spiel. It’s a messy ragbag of oddball characters. No longer big business, it nonetheless is a business – the more notorious end of which commands prices in excess of the average car, or house. And where’s there’s brass, there’s muck. Accusations of snake-oil peddling are thrown by all parties in all directions. There’s a suspicion (not unfounded) that interests are vested in solving problems that don’t exist – but little consensus on who the good guys are: one man’s pioneer is another man’s charlatan.

It’s not in the nature of Western democratic economies to co-operate toward the resolution of a common goal. Companies compete. Products proliferate. Branding demands differentiation. The audio market still operates largely on the basis of loyalty to a ‘house sound’, or a ‘look’ – often, the lion’s share of production cost is spent on branding a handsome case advertising the extent of your disposable income to friends – while simultaneously (in an ideal world) disguising the enormity of your purchase from a significant other. Most manufacturers specialise in – and therefore stress the essential nature of – one component at the expense of the whole system. Muddled priorities abound: no-one sells rooms – therefore no-one tells customers how important the room is – therefore the zeitgeist is that the room isn’t important enough to warrant spending on. This commercial tribalism hasn’t been helpful in advancing a general understanding of what fundamentally makes an audio system work well.

Another taproot of such tribalism is widespread – inevitable – subjectivity at all levels. Listeners have particular (sometimes peculiar) priorities and pet peeves, and A Thing that pushes their button – rendition of voices, dynamic range, resolution, timbre, soundstaging and in-room presence, etc. Many tribes inhabit the audiophile landscape.

While customers frequently aim at a single, or reduced array, of metrics of accuracy, the aim of the manufacturer is high levels of across-the-board competence within budget parameters. Briefs derive from commercial niches – eg: “Develop a small two-way passive speaker retailing for £2000″. Initial, broad-brush decisions about driver choice, cabinet construction and crossover components are already constrained by the budget: to turn a profit, the parts bill can’t exceed £200. Thereafter, guided by the designers’ experience and premonition, hundreds of choices are made from millions of possibilities. A component’s ‘voicing’ derives from the specific synergy of their combination. Although this process is technically based, and driven by the overarching requirement to measure correctly, fundamentally an audio component is destined to be listened to by humans and is usually signed off only when listening tests are satisfactorily completed.

We touch on the vexed issue of subjectivity v objectivity in a later chapter, but it’s worth noting at this point that the greyest of greybeards will frequently note that they’re still working out wrinkles in their game after half a century trying. More often than you might think, experienced designers will explain they specify a particular topology because it works, without knowing precisely how or why. And the process of listening itself isn’t perfectly understood in general – let alone in the case of every listener. Bias, subjective preference and plain error are the accepted order. Jazz musicians call it ‘improvisatory’.

The audio business has barely any regulation or benchmarking beyond ensuring customers are protected from electrocution. We don’t have a hi-fi business that operates a points scale on which cheap equipment buys the owner 50% fidelity and the most expensive equipment guarantees 100%. In the cinema market, ‘THX’, for instance, is a notional concept that hinges on paying a royalty to Dolby as much as it acknowledges minimum distortion levels at reference SPL.

From the gramophones of 100 years ago to the digital streamers of today has been a mazy, meandering path – pulled hither by fads, pushed thither by public and professional opinion. There have been revolutionary insights and rapid progress and – arguably outweighing these – much misguided effort. The record industry has steered the market into more cul-de-sacs than certain elements of the audio press have perniciously steered readers into decisions that favour only their advertisers, creating eddy currents of popularity around a handful of spotlit products.

It’s been entertaining, but confusing. For every new technology that emerges, there’s a counterswing toward the past: vinyl never died, and in fact flourished in the 2000-2020 period while CD sales plummeted. Mobile devices wirelessly streaming MP3s dominated in this period, while many serious audiophiles seriously rocked 1940s technology: big paper cones, horns, and turntables. The specialist audio computer marked struggled to make headway against the ‘bits are bits’ brigade from 2000-2010; ten years on we see a diverse and proliferated market and a greater understanding of how important the digital ‘source’ is . . . cycling back on Linn’s ‘source first’ mantra of the 1970s. The audio industry, like the music industry, tends to such circularity.

But what is the ‘source’? From the most literal auditory perspective the source is vibrating air created by room/speaker interactions – a long way down the signal path from the turntable. As we’ll see, it’s helpful to take a step back and consider what a hi-fi system is, in order to dispel the ‘box myth’. Myth-busting is a big thing in the audio world. We even find myth-busting of the myth-busters. Clarke’s 4th Law applies: It seems that for every expert there is an equal and opposite expert.

Our expertise stems from several decades system building as manufacturers, distributors, resellers and consultants. A constant feature of liasing with audiophiles over this time is confusion: confusion over conflicting reviews; confusion over conflicting theories – but very often a failure to ask the right question, and the underlying assumption that upgrades – sexy metal boxes – are magic bullets, panaceas. Naturally the audio industry does everything to encourage such a mentality for its own benefit. Frequently as dealers we found ourselves in an uncomfortable position where it was necessary to talk punters down from overspending on something from which they were likely to derive little benefit, given more major issues extant in their system. Visiting customers’ homes, it quickly becomes obvious that – for instance – the character of the room is prohibting high-end reproduction, regardless of how much money they throw at equipment. Shockingly often we have visited the listening rooms of small-scale manufacturers and found the same issue – as have many visitors to audiophile shows. It seems there is a need for a general guide to system building.

Principals of Audio aims to cut through 100 years of smoke and mirrors and offer a simple but reliable overview of high performance music reproduction, rethought from first principles. For various reasons, many of these guidelines are well known but little practiced – and therefore we believe will not be controversial. Little specific product advice is offered: markets change quickly but the fundamentals are constant. It is hoped that the followed guidelines will help audiophiles of today and tomorrow to maximise their listening pleasure by making the right mental adjustments before taking steps to purchase equipment.

Comments on the ‘current’ state of the industry are relevant to the time of writing (2019) and will be updated in future editions.

CONTENTS

  1. There are no good small passive speakers – why active is better; why sometimes it isn’t.
  2. Digital audio – beyond ‘bits are bits’. Jitter, timing, sampling filter, noise, SPDIF v USB. ‘Character’ = distortion: bits are bits = sound of no sound. What matters, what doesn’t. Reclocking pros and cons. Navigating the interface and why it matters.
  3. The cable scam – overpriced, not over-rated. Why speaker cables vary (passive network). Why interconnects vary (impedance, resistance, screening).
  4. Subwoofers – under-rated. The importance of multiplicity. Bass is a room function; mid/treble is a function of the listening triangle
  5. Amplification – over-rated. Why? Coming of age of low-distortion technology: from Tripath to Class D.
  6. Power – appropriately rated, but often badly applied. Mains fix. Batteries. Isolation transformers v Huge expensive of reconstruction / filters, etc. Fix problem at source.
  7. The room – underrated. What can you do? Know your room. EQ v physical correction. Fix problem at source. Different solutions for listening rooms and living rooms. The headphone advantage.
  8. To pre or not to pre? Canvas size v micro-resolution. Cable losses. Cost.
  9. Vinyl. Differences between vinyl and digital, when vinyl taken from a digital master. What matters, what doesn’t.
  10. Gadgets: vibration support, cable lifters, things that wrap around cables, etc
  11. What to spend on what? The 80% rule. Source first? Buying used: YES (passive speakers, DACs, cables, stands), MAYBE (active speakers, amplifiers, turntables), NO (subwoofers). Why? What things actually cost: lifting the lid on margins: pro v audiophile. Never buy on a review, or on spec. Always listen first.
  12. Thinking out of the box – the box myth. Hi-fi sold in boxes (magic bullets), but a system is a single entity without borders. Deleting connectors. Holism. Think stages. Good/bad combinations of stages in boxes (pros and cons). Parasitic noise.
  13. The golden rule of system building: let the room choose the speakers (size, placement – also subjective tonality preference – horns, ribbons, cones). Let the speakers choose amplification (inefficient/small speakers need big power; efficient speakers tend to favour low power). To pre or not to pre? (Pros and cons – inc digital/vinyl/multiple inputs). If vinyl, ???. If digital, make the DAC happy (ie, USB, AES, SPDIF – the hierarchy). The digital source should only be transparent – why the ‘sound of nothing’ is expensive.
  14. Don’t fix problems. Remove sources of problems.
  15. On Listening. Ladder of acuity; experience. Paucity of language; the description problem. Deconstructing the blind test scam. Myth of ‘You can’t tell how a recording is supposed to sound’ (Comparative analysis). Types of listener: brand loyalist / flat earther / 1930s man / 1970s man / headphonista / studio monitor guy (electro) / hardline objectivist / only vocals / headbanger / valve obsessive / digital aesthete / horn people / stat-lovers / lifestyle obsessive / nervosa repeat buyer / everyone into jazz. Subjectivity v objectivity.
  16. Defining neutrality. Different metrics of accuracy: phase coherence, timbre, micro-detail, soundstaging. Euphony. Is there a ‘right way’?
  17. The pro world v the audiophile world: Cultural differences (cables, clocking, power) and similarities (accuracy, subjective preferences)
  18. Gain structure and impedance-matching issues
  19. Recipes that work – leaning into a small room (the 6-8″ 2-way active); battery power and high efficiency; ribbons and pro amps, multiple subs
  20. Laws of physics: what’s the right size/material for a tweeter, mid, bass driver? Bass in small rooms ? Dipoles. Dispersion geometry.
  21. Implementation matters more than technology type or available budget.
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