Articles and whitepapers

Built-in Home Entertainment - Custom Install Comes of Age (2/2/2005)

By Bob Abraham, Armour Home Electronics

It all started in the US back in the early 1980s. Custom install was born out of matching the needs of rich clients in places like Miami and California with bespoke A/V solutions. The term 'custom install' was used to describe this type of installation, although 'Heath Robinson' would have been better, since control was via externally-driven relays connected via long trailing wires soldered to various points inside an electronic source component. Even in-wall speakers where just 'hacked about' versions of standard product. Indeed, Sonance started by buying product from Boston Acoustics and cutting the cabinets off!

Whilst we have come a long way since then, vestiges of that Heath Robinson beginning still colour the market perception of both built-in home cinema and multiroom audio/video installations. The danger is that we, as an industry, are presenting an image of something that is desirable, but for most unattainable, whereas we should be offering solutions which are desirable and attainable. To use a car analogy, we should be offering BMW 3 series, rather than Ferrari Testarosa. Clearly there is a Ferrari market, but if we are to make our products more attractive to the broader market, we have to think a little differently.

This is particularly evident in the new build sector where, having sown the seeds in the early 1990s, we are nowhere near where we should be in terms of properties being pre-wired. For too long, we have been thinking 'custom' rather than 'template' solutions. Like the clothing industry did many years ago, we need to offer more off-the-peg solutions.

The case for category 5 wiring

When we at Armour Home Electronics looked at this some three years ago, it was obvious that what was needed was a complete rethink in terms of wiring and form factor (size and shape). From a wiring point of view, a standard already existed, namely Cat5 (category 5) wiring. This has been used in all office buildings for many years to provide a network and telecoms infrastructure. In the US, it is now commonplace for residential properties to be wired on a similar basis, and this is starting to happen in the UK as well. This method of wiring is often referred to as 'structured wiring.' The advantage of going down this route is that the wire itself is incredibly cheap and readily available. Bolting on a multiroom A/V solution to this wiring topology makes sense for everybody.

Audio over Cat5

Using UTP (unscreened) Cat5 cable, rather than conventional speaker cables, does present some serious technical challenges, and calls for some thinking outside the box - literally. Sending audio down Cat5 is relatively easy. By adopting transformer-based balanced line transmission, similar to that used in the pro-audio market, it is possible to transmit audio over long cable lengths with virtually no signal degradation and very high immunity to hum and interference. This approach is in fact a higher-quality solution than conventional speaker cables, but it does require an amplifier to be located in each zone, rather than a central stack. This means that there are other issues to deal with - principally concerning the transmission of power down the Cat5 cable to drive the in-zone amplifier.

Power over Cat5

Conventionally, power connected over a Cat5 cable would suffer from a number of problems. Firstly, power would be lost via heat in proportion to the length of cable and the current being drawn by the amplifier. Consequently, the performance of the amplifier would be very different over 1 meter of cable compared to say 50 meters. Over 50 meters, the voltage would drop according to the power drawn by the amplifier, and given that the greatest power is drawn when reproducing bass notes, the voltage rail would drop at the very moment you did not want it to. The end result is not just loss of power, but also dynamic compression.

We have overcome this problem by providing the zone amplifier with its own purpose-designed switched mode power supply which uses high-frequency pulse-width modulation as a means of compensating for variable input voltage and change in current demands. We then pair this with Class D amplifiers which, because of their efficiency, can operate on lower voltage rails for a given output than conventional amplifiers can. Also under quiescent current conditions, these amplifiers draw very little power and therefore generate very little heat - a major plus point. Such an approach provides the very best solution in terms of sound quality, because it efficiently delivers a fully-regulated power supply right next to the amplifier.

The other option is, of course, to pick up power in the zone, but this is often inconvenient, particularly when using active speakers located in the ceiling.

Profile of a Systemline ceiling speaker

A big advantage of placing amplifiers in the zone is that it facilitates not just a local stereo input such as an MP3 player, PC or TV sound, but also, using multiple active speakers, true 5.1 home cinema sound. By using the discrete 5.1 audio outputs of a DVD player or home theatre all-in-one, it is possible to seamlessly switch between local 5.1 sound and central multiroom A/V sources replaying stereo through all six speakers.

The Systemline learning remote

Other data over Cat5

Data and IR transmission is relatively easy. Cat5 is already used for Ethernet, so bandwidth is not an issue. Video distribution in multiroom systems however, has traditionally been via RF modulation. This method is problematic for several reasons. Firstly, this is technically the poorest-quality method of video distribution. Secondly, bandwidth limitations make it difficult to modulate more than a couple of sources without encountering interference problems and thirdly, from a user perspective, changing the audio and video sources requires separate button presses on the handset (one to change audio and the other to switch the TV to a different channel - assuming the user remembers which channel to select!). Clearly, this is a non-intuitive, inelegant solution. The alternative is to create a dedicated video matrix-switching box that is driven automatically by the audio switching box, thus making A/V source selection completely seamless - again over Cat5 to ensure compatibility with structured wiring topology.

Hiding the hardware

The form factor of a product designed for structured wiring topology is much more suited to being built-in to a new home because it avoids the need to locate and connect a large central controller that would normally take up valuable living space. Indeed, by placing the amplifier in the ceiling and connecting the source equipment via a simple wall socket, this type of system is very space efficient and non-intrusive. The modular nature of this solution results in a highly-scalable product proposition, making it suitable for anything from small 1-2 bed apartments up to 6-7 bedroom homes offering single-source and multi-source audio or multi-source audio/video.

A non-intrusive hub

Conclusion

By designing a new type of multiroom A/V product, it has been possible to much more closely match the needs of the new-build and self-build markets. As a result, it is going to be increasingly commonplace to choose from built-in home entertainment options when buying a new home, as it is now for choosing factory fitted in-car entertainment in a new car. And like a new car, many homes will have systems pre-fitted as standard. The age of built-in home entertainment has at last arrived.

Bob Abraham is the Business Development Director of Armour Home Electronics. Armour Group PLC comprises two divisions: Armour Home and Armour Automotive. Its portfolio of brands includes Autoleads, QED, Systemline and Veda, as well as the niche brands Soundstyle, Goldring, CTI, RM Audio and Mutant.

www.systemline.co.uk