Looking to put together your own hi-fi system but unsure where to start? Baffled by the audiophile terminology littering the pages of your favourite hi-fi magazines? Simply not sure what to believe? It seems you’re not alone – in fact, these questions are posed to me on a regular basis by not only Audio Appraisal readers, but also people in various social circles.
A quick search of the internet will reveal a wealth of information concerning the topic of hi-fi. Some is based on fact, and aimed at the beginner – yet fails to fully explain the bare basic components of a system. Some are based on the writer’s opinion, and if you’ve spent any time reading an audiophile magazine or indeed an online forum, you’ll know that opinions in the audiophile community are extremely diverse, and debates are often fierce, making the hobby seem daunting for beginners.
Some are purely written to sell a specific product (or set of products). And some are aimed at the DIY enthusiast, and thus are inappropriate for somebody wishing to simply compile a set of components into a working system. It is my aim to produce a comprehensive guide, designed to help you take your first tentative steps on the hi-fi ladder.
Throughout this guide, we’ll explore the names of the components of a hi-fi system, their responsibilities within the system, and the various features a given component may offer. We’ll teach you how to connect everything up, explaining the types of cables and the pros and cons of balanced and unbalanced connections. We’ll touch on cables, and explain exactly why they’re the subject of debate among audiophiles. And finally, we’ll talk about getting the best from the components you’ve chosen and how to make your investment worthwhile.
Keep in mind that the components you choose for your system will depend on your needs and expectations. Nobody can choose your components for you – they can only advise you on what is best, based on their own experience. Ultimately, irrespective of the components you’ve chosen, the goal is simple – to take your musical enjoyment to another level.
First up, the terminology. Throughout this series, you’re going to see me repeatedly use several key terms. Many of these are explained in detail in the relevant sections of the guide; however it’s best that you have an understanding of a few basic audio terminology before we get started.
An audiophile is a general term used to describe a person who is enthusiastic sound reproduction. Similarly, an ‘Audiophile Recording’ is nothing more than a recording made with special attention to audio quality.
A capacitor is 2 conductors (a material or substance capable of conduction electricity) separated by an insulator or a non-conductor. Capacitance is, as so concisely put by Wikipedia, “the ability of a body to hold an electrical charge”. Capacitors in modern electrical devices are purpose-built to hold a charge (like a quasi battery). Even cables can exhibit capacitance, as a multi-wire cable (such as a speaker cable containing 2 conductors) is, in its simplest form, a capacitor – 2 conductors separated by an insulator (in the case of a cable, the plastic insulation layer).
Measured in Farads, usually PicoFarads in the audio world – where more often than not, especially where cables are concerned, the lower the capacitance value the better. In context, if a cable is acting as a capacitor and storing an electrical impulse, there will be a minute time delay on the signal – in other words, the electrical signal won’t get where it’s going in time, which can have a negative affect on the music.
A ‘channel’ is nothing more than a single stream of audio information. Usually in hi-fi terms, the word channel is used to denote the separate streams of audio being produced from each separate speaker. To put this into context – a standard stereo system, often referred to as a ‘2-channel’ system consists of 2 channels, left and right. These left and right channels relate to the left and right speakers that form a stereo pair.
In a multi-channel system, such as a 5.1 or 7.1 surround sound system, the basic principal remains the same. Each individual stream of information is its own channel, and a single speaker (whether it be your front speakers, centre speaker or surround speakers) receives a corresponding channel of information.
The ‘.1’ designation denotes the presence of a sub woofer, designed to re-produce low frequency signals. If a system contains more than 1 subwoofer changes to reflect that – for example, a 7.2 channel system consists of a total of 9 channels of information – front left and right, 4 surround channels, 1 centre channel and 2 sub woofer channels.
Clipping is a type of distortion and is the result of an amplifier being overdriven in an attempt to deliver a current beyond its maximum capability. While driving an amplifier into clipping can cause it to produce an output power in excess of its specified ratings, doing so often results in damage to speakers and in some cases the amplifier itself.
The ‘Frequency Response’ denotes the minimum and maximum frequency a transducer (or a speaker) or an audio component is able to reproduce. Frequency response is typically measured in Hertz (HZ) and kilohertz (KHZ) which is simply a measure of a thousand hertz.
Generally in hi-fi terms, a low frequency response results in more bass, and a higher frequency response results in better high-frequency presentation. Typical stereo components have a frequency response ranging from 20HZ to 20KHZ (or 20,000HZ) – though many modern components far exceed this specifications with some components able to deliver frequency responses of up to 1HZ – 100 KHZ.
When discussing audio, ‘Gain’ is an increase in the power of a signal. The term ‘gain’ differs from the term ‘volume’ in that the volume is used to describe the power level of the signal. To put this into context, a typical amplifier specifies a maximum amount of gain that it can produce when fed with its maximum input signal. The volume allows the end user to control the level of the sound from zero up to the amplifier’s specified maximum gain.
Headroom refers to the amount by which the signal-handling capabilities of an audio system exceed a designated level. Put simply, headroom can be thought of as the safe zone, in which transient audio peaks (or ‘spikes in the music) cannot damage the audio system or audio signal. Clipping is the result of exceeding the headroom of a given audio system.
The term ‘high-resolution Audio’ refers to an audio recording that has a bit depth and sampling rate greater than or equal to 24-bit, 48KHZ. To put this into perspective, the bit depth and sampling rate of a CD is 16-bit, 44.1KHZ. A higher sampling rate and bit depth results in more audio information, often resulting in a more detailed, realistic sound.
Think of high-resolution audio as being similar to high-definition video or imagery. A 1080P (full HD) image looks better than a 640×480 (VGA quality) image, primarily because the image is of greater resolution. It’s the same with high-resolution audio – the more available digital information, the better the sound quality.
Impedance is a measure of the opposition that a circuit presents to a current when a voltage is applied. In hi-fi terms, each electronic component has both an input and output impedance, which for best results should be matched as closely as possible. Loudspeakers also have an impedance rating – said rating, along with the loudspeaker’s efficiency, serves to indicate the level of demand the loudspeaker will place on the driving amplifier. A speaker will lower impedance will typically require more power to drive to produce the same sound level as one of higher impedance.
Phono is nothing more than an abbreviation of the word ‘Phonograph’, a term used to describe the device invented in 1877 by Thomas Edison for the mechanical recording and reproduction of sound. This device we now know as the phonograph record or more commonly the ‘vinyl record’ – yet the principal is still the same.
Phono can also refer to the type of connectors used on single-ended analogue hi-fi cables – more commonly referred to as RCA connectors, these connectors feature a central positive pin and an outer metal ring used for grounding. Throughout this guide, they will be referred too as RCA connectors, or RCA/Phono connectors.
Sampling Rate and Bit Depth
The term ‘Sampling Rate’ refers to the number of times an analogue signal is measured in samples per second. Put simply, the sampling rate is the number of samples of a sound taken each second and used to digitally represent the audio information. The more samples taken per second (or the higher the sampling rate), the more accurate the digital representation of the sound can be. The term ‘Bit Depth’ refers to the number of digital bits in each sample of audio.
To summarise part 1 – thus far, we’ve introduced the series, and covered some key terminology that you’ll find invaluable throughout the remaining posts. In part too, we’ll begin covering the components – starting with the amplifier. Until next time…
Continue to Part 2