Mini Hi-Fi Sound Systems: An Introduction

A Brief History of Home Audio Systems
The earliest known audio recordings date back to the late 1800s. Various playback devices were invented, eventually evolving into the iconic gramophone we all know for its large horn.

Vacuum tubes (valves) came along in the early 20th century, allowing for the amplification of electrical signals. This enabled sound from stereo recordings to be produced via modular speakers that sit a distance apart from one another to trick the listener’s ears into imagining a 3-D soundstage only steps away.

Digital audio technology advanced to the point where it started showing up in homes during the 1980s. The various home audio options continued to grow in their capabilities and made way for the lineup we have available today.
Meanwhile, purely analogue systems gradually faded into becoming a niche for enthusiasts which persists.

Modern Hi-Fi System Components
Hi-Fi, short for ‘high fidelity,’ refers to playing back a recorded audio source as accurately as possible. Typically, a Hi-Fi sound system contains several separate pieces of equipment arranged in a chain as follows.

Audio Sources: These are the items that read a recording from media (such as a record, CD, or MiniDisc) or interpret a stream of audio data (from Spotify, etc.).
Digital-to-Analogue Converter (DAC): Digital audio sources’ data must be converted into an analogue waveform that speakers and headphones can mirror.

Preamplifier: Provides volume control and switching between multiple audio
source components that a user might want to hook up simultaneously.
Power Amplifier: Draws additional electric power to boost the analogue signal it receives and sends it to the speakers.
Output Devices: Various kinds of speakers, headphones, earbuds, etc.

Hardcore audiophiles with deep pockets enjoy carefully selecting each component separately to get exactly the configuration they want — the more expensive and exotic, the better! However, thankfully, there are integrated systems that are much simpler, more compact, and easier to use for the rest of us.

Hi-Res Audio Technology
For decades we’ve been told that the CD format represents ‘perfect sound forever,’ but in fact, there have been well-known problems with the format.
Hi-res audio technologies aim to solve them.

An analogue source such as a vinyl record in perfect condition provides the complete audio waveform recorded. This is why many enthusiasts still love them today. In contrast, digital files can only approximate the original sound wave because they had to divide it into 1s and 0s during digitisation. Those 1s and 0s create a snapshot of the sound wave similar to how a single frame is a snapshot of a film.

Hi-res (high-resolution audio, high-definition audio, or HD audio) refers to digital audio files with more excellent resolution than standard CDs, often matching the digital master recordings from which the CD was produced.

Sound resolution is measured in terms of bit depth (bits) and sampling frequency kHz. kHz and bit are units that indicate the amount of information in digitisation. The sampling frequency (kHz) and the number of quantisation bits (bit) are the units that indicate the quality (amount of information) when cutting out the original sound. For a CD, those numbers are 16 bits and 44.1 kHz, respectively, whereas high-res is typically 24 bits and 96 or 192 kHz.

Similar to how a wider colour gamut and faster frame rate increase the accuracy and smoothness of video, greater bit depth and faster sampling rate increases the natural-sounding character of digital audio. Bass notes gain more texture, mid-range frequencies gain life and realism, and the treble becomes airier, with more precise decay and a more realistic soundstage. All the while, rhythm is preserved more precisely through a filter that causes a type of audio distortion called ‘aliasing’ — when different sounds are indistinguishable from one another — to operate at a frequency further outside the realm of human hearing. This reduces a time shift phenomenon which, while normal human ears can’t hear it, can undoubtedly be felt.

Two-channel Stereo Systems
Like antique cars or fine wine, the oldest format for Hi-Fi sound, the two-channel stereo system, is the most respected by many audiophiles. However, it is also the most expensive, impractical, and difficult to maintain.

They quickly get more complicated as upgrading typically means adding specialised pieces of equipment. Indeed, it is a hobbyist’s dream, with endless ways to upgrade and opportunities to tinker. But high-end, two-channel audio equipment can be costly and take up substantial space.

It can be utterly rewarding for a connoisseur of live albums or well-recorded acoustic music with the budget and space. However, it is impractical for most casual listeners.

Surround Sound Systems: These are purpose-built sets of speakers and amplifiers designed to be easy to connect to the TV. They are pretty affordable and ideal if you only use the room for watching movies or TV shows.

Soundbars: These boast simplicity, plug-and-play user-friendliness, and hardly take up any space. Many of soundbars have surround sound function to enhance the sensation of 3-D soundstage.
 

Bluetooth^® Speakers
At the lower end of the spectrum are all-in-one Bluetooth speakers. These are ideal for those with minimal space who want maximum convenience. Plug it in, wirelessly connect your phone via Bluetooth or Wi-Fi, and stream music. Put it anywhere; on a counter, a headboard or shelf, or toss it in your work bag or picnic basket, since many Bluetooth speakers can run on battery power.

They’re relatively inexpensive and come in a variety of shapes and sizes. However, if you don’t play music from your phone, you will have little use for a Bluetooth speaker as they typically can’t connect to other audio sources. Furthermore, their compact size means filling a large room with sound can be difficult. Their fixed speaker configuration lacks the stereo separation required to create a believable 3-D soundstage — straining the definition of ‘Hi-Fi’ sound.

Mini Hi-Fi Sound Systems
None of the above represents a comprehensive, user-friendly audio solution that covers both music and TV. What about people without a two-channel audio setup or with an irregularly shaped home theatre space? Or those who want a true Hi-Fi stereo with lots of connectivity options but can’t give up half of a room for the equipment? Fortunately, another class of audio products has existed for decades, almost under the radar compared with more modern configurations. You have probably walked right by it at the electronics store: the mini Hi-Fi sound system.

Mini Hi-Fi sound systems are made to fit anywhere, from a bookshelf to a tabletop, a kitchen counter, to a desk. Yet, they’re still able to reproduce realistic, believable sounds. Lacking a dedicated listening room doesn't make great-sounding music any less important, after all.
They are also known by other names. They usually use the prefix ‘mini,’ ‘micro,’ or ‘compact’ paired with ‘Hi-Fi,’ ‘stereo,’ and/or ‘system.’

These systems also connect easily to TVs. This is advantageous because, unlike a full-sized Hi-Fi audio system or a surround sound speaker setup, a mini system sits easily on a TV stand or a shelf. And though a mini Hi-Fi sound system can’t recreate the surround sound of a film’s soundtrack, a good one can produce much higher fidelity audio than a soundbar. Many people find this results in a sound that, thanks to accurate audio detail and spatial imaging, sounds satisfyingly 3-D.

Optimal Speaker Placement
As with any Hi-Fi stereo system, careful speaker placement is required for the best possible audio experience. Unlike an all-in-one speaker, a mini Hi-Fi sound system has modular speakers separate from the body housing the electronics. These speakers can and should be separated for optimum stereo effect.

An oft-repeated piece of advice is that listeners start by placing the speakers on a flat surface at ear level when seated so that the distance between them and the listener creates an equilateral triangle for optimum sound staging. Make sure the tweeter is on the inner side and speakers are placed symmetrically. Realistically, given that compact audio systems are often used where space is tight, and the seating position (for example, the living room sofa) isn’t adjustable, creating that triangle isn't always possible. And that’s okay.

Two other positioning considerations impact the sound: distance from the wall behind and speaker toe-in (the angle at which the speaker points inward towards the listener). As tempting as it may be to push a mini Hi-Fi system back against a wall and out of the way, this is generally not recommended because doing so minimises the 3-D sense of depth that a Hi-Fi system is designed to create. Also, make sure that speakers and the central integrated unit have at least 10 mm of space between them, as the central unit generates heat with use and requires a minimal amount of ventilation.

Starting with the speakers against the wall*, listen to an audio track focusing on depth and scale. Jazz combo music and piano solos tend to work well for this test; pop music does not. Then, pull the speakers out away from the wall as far as you can and listen again.
The difference may surprise you if you haven’t tried this before. Finally, push the speakers back just an inch or two, listen again and repeat, until you’re satisfied with the compromise between positioning and audio depth of field. If you have a rigid wall or a glass interior that reflects the sound too much, try installing drapes over them to absorb sound.
*It is recommended that speakers are placed at least 50 mm away from the wall.

By contrast, toe-in impacts the width of the soundstage and the focus of the centre image — that is, the sensation that sound is coming at you from a speaker dead centre between the right and the left channel, even though no speaker exists there. Similar to the depth-of-field exercise, toe-in is a matter of compromise since the centre focus typically decreases as soundstage width increases. To find the compromise that works best for you, start with your speakers facing straight out into the room and listen to your test track again. Note where the leftmost and rightmost sounds are coming from, and if there's a vocalist or another instrument that sounds as if they are in the centre of the group. Pay particular attention to how much it sounds like that person is there, in the centre. Then, tilt each speaker inward slightly, just 5 or 10 degrees, and listen again. The speakers belong in the position where the soundstage feels realistically wide, yet the centre image is also sharp.

Care and Maintenance
Like any high-precision electronic device, a mini Hi-Fi stereo like the SC-PMX802 requires care and maintenance to deliver years of healthy use and enjoyment. Here are some care and maintenance tips.

Power: The system should be unplugged when unused for extended periods since it is susceptible to power surges. Be sure to unplug it during thunderstorms.
Protection: The unit should be kept dry, out of direct sunlight, and free of dust and dirt.
Also, speakers do not have magnetic shielding. Do not put them near TVs, PCs or other equipment easily influenced by magnetism.
Volume Control: When you hear the sound getting distorted, decrease the volume to prevent damage. You play at high levels for a long period, it can cause damage to the system and decrease the life of the system.
Updates: Be sure to keep the unit connected to your Wi-Fi to receive critical firmware updates.

Conclusion
Like many hobbyists, audiophiles pride themselves on the exclusivity of their Hi-Fi sound systems. But whereas once the listening space in front of a turntable was where a family gathered to relax and socialise, today’s overwhelming entertainment options mean that dedicated music listening isn’t often a primary purpose of the living room. Increasingly busy lifestyles and compact living spaces might dictate that a dedicated listening space might not exist at all.

Panasonic has bridged these two worlds by making world-class audiophile sound accessible to listeners with almost every conceivable circumstance. This combination of features, flexibility, and value represents the democratisation of Hi-Fi audio. The SC-PMX802 mini Hi-Fi sound system is unsurpassed in Panasonic audio products as its torchbearer.