Some Thoughts on HiFi

The term HiFi can mean different things to different people. It once connoted a monaural (pre-stereo) system. To today’s hipsters it’s a retro term for a serious 2-channel stereo rig. To the general public it’s any kind of music system. To the engineers who design them and we who sell them, it is a collection of parts (components) packaged in various combinations, with a defined set of conventions and specifications, inputs and outputs, that can provide a musical performance in your home. In this post I’ll try to explain how this ‘audio guy’ sees it.

First, my own bias. I am not ashamed to admit being more of an “objectivist” than “subjectivist” at this stage of my career. That may have to do with some decline in my hearing acuity at age 62…and having long ago given up recreational consumption of “sensory enhancement” herbs! I always cared a lot about what makes one component better than another in the reproduction of sound, and not being an electrical engineer, I read extensively in the literature to learn what I could, and I’ve listened to a lot of gear over the years. I have often noticed that components and speakers exhibit audible properties not easily explained by their basic specifications, but my firm belief is that all such phenomena do have reasons, if one looks more closely.

A real HiFi is an apparatus whose purpose is, as completely and accurately as possible, to convey the recorded sound from the source medium back into the listener’s room. The onus for “good sound” or a pleasing listening experience falls first on the recording itself, then to the acoustics of the room in which the reproduced sound is played, and finally to the qualities of the HiFi components and how the are matched and set up…you can no more expect accurate reproduction of a bad recording to sound good than you can expect a good one to sound good in an bad sounding room, or with poorly set up or mismatched gear. I reject the “absolute sound” pursuit…even the most faithful reproduction can fall short of achieving that elusive goal through no fault of its own due to external factors. But experience has taught that accurate reproduction comes closer to simulating natural sound more often than tonally distorted reproduction does…if you are judging using the right source material and setup.

The HiFi system

…consists of sources: CD, phonograph, digital music files played from media streaming devices, broadcast or internet radio, etc. The sources are connected to amplifying devices: the pre-amplifier which selects from the sources and regulates its volume (and tonal adjustments in some cases), and the power amplifier which adds the final boost to make the speakers play. To be Hi-Fi, each electronic component must process the full audible frequency spectrum evenly, without adding or removing anything. Errors in this core task include frequency roll-offs at the low or high ends of the spectrum, and the addition of noise and unwanted byproducts of amplification to the music signal. These characteristics are quantified in the “frequency response” (e.g. 20-20KHz ±1dB), signal to noise ratio (e.g. S/N -90dB) and “THD” or “IMD” (e.g. ≤0.05%) specs of the component. “Noise” can be a steady background hiss or a more pernicious form that modulates with the signal. Even when carefully measured, these basic specs tell only a partial story about the quality of sound a component is capable of. Some components seem better able than others to convey a sense of “air”, or spatial realism, or possess more “effortless” musical flow or dynamism, despite having specs that are not easily distinguishable from components that reveal less of these desirable musical traits. These are the areas where “audiophiles” focus their listening skills, and where the best manufacturers show their stuff.

While there are broadly speaking few “compatibility” issues in connecting most components, there are a few areas where attention is required…mismatching a phonograph cartridge to its pre-amplifier can lead to audible hum or noise, and a power amp must play well with its speakers. Audible distortion or in worst cases overheating and system failure can result from bad choices made in this particular. Mixing tube and solid-state components can sometimes introduce mismatches. Components must also be connected to one another with various kinds of cables, whose sonic effects can vary from benign to positively distortive, and while much ink has been spilled on this topic, it is in truth still little understood, and its significance is mostly overblown by cable makers pushing their agenda.

Demoing Speakers

In my opinion, to use one’s ears to assess the quality of a stereo playback system one needs to use demo material of the highest quality that uses unaltered acoustic instruments recorded with as little studio production as possible. Classical chamber music, art song, folk, acoustic jazz, or singer-songwriter performances are generally best. Live-to-2 track recordings give the listener the most to go on in assessing imaging, and avoiding amplified instruments allows you to listen for subtleties in the tonal quality of performance that are distorted by the electric process of amplifying. If you do use music with amplified instruments out of preference for the music, that’s fine, but you are depriving yourself of the best chance you have to discover potential colorations introduced by the playback system. If a system succeeds in achieving realism with acoustic material, then it will also faithfully render recordings made using commercial recording techniques. It may also reveal more clearly the ill-effects of too much production.

Equally important for the listener, the speakers under consideration must be placed a proper distance apart, away from nearby room boundaries, and you must position yourself at the apex of an equilateral triangle thus created, with your ears near the level of the speaker’s tweeters. Is this a practical arrangement? Maybe not, but it is the basis upon which the principle of stereo sound reproduction rests. Speakers are designed to operate under these conditions, so not only does it make sense to allow them to reveal how well they succeed by observing these guidelines when demoing, it also makes sense to observe them in your home if at all possible.

In the demo room, each speaker system to be compared must be afforded these same advantages if the demo is to be meaningful. This is not easy or convenient for the retailer to do, but it is essential, because the alternative allows the difference in speaker placement to become a significant influence on what you are hearing.

Summing up

What are the challenges a High Fidelity system designer faces? The objective is to give the listener a complete and faithful representation of what was captured by the recording process from each and every source… analog or digital, broadcast or streamed, or played from a spinning disc. This goal should be met in the room where the system is used…speaker size and acceptable placement options, the practicality of concealing unsightly wire runs, the proximity to amplifier and sources, available control mechanisms for items not in view, all have a place in the equation. Even the integrity of your house electrical supply and the presence of RFI or EMI in your area play a part. For today’s systems, the strength of your WiFi and home computer network are also increasingly relevant.

This is some of what we do at Audio Concepts…use our knowledge, experience, and passion for music to offer practical solutions to fulfill our clients’ desire for quality music in their homes.

Next post…In-Wall and In-Ceiling speakers for high fidelity, in both stereo and surround contexts.

Thanks for reading!

Lewis Dalven