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If you are wanting to distribute high-definition images around your house, then you currently have
to consider the more expensive options, such as matrix switchers, because the current crop is focused
around RCA sockets.
Switching
The cheapest piece of necessary equipment is an AV switch box, or AV source selector box. This provides
multiple inputs for your various devices, DVD, PVR, VCR, and so on, and routes one of these to the TV
output. Most equipment give you the option of using either S-Video, RCA, or SCART inputs. This
naturally requires that the TV is always set to receive the input from the box, not its internal tuner. There
are many switch boxes available, so the features to consider are as follows.
Infrared remote control: This is a necessity, really. Since this box is now taking
the place of your TV channel changer, it must have the functionality you’d
expect from the TV which at a bare minimum is a remote control.
Active or passive devices: Active units have a small amplifier in them and
therefore need power. These ensure a strong signal but at the expense of a
lower quality on the cheaper models, since their internal amplifier isn’t as good
as the ones on the DVD player or on a TV. Passive devices have no such
amplification and are more likely to lack an IR remote.
Input connections: Although some boxes provide S-Video, RCA, and SCART, for
each input they might not be interconnected. That is, the RCA input socket
might only be connected to the RCA output socket, and not to the S-Video or
SCART. Since you only have one output to the TV, this requires you to
compensate for adapting your interconnects to the most common form factor
and to convert every other input into the same type of plug (there are
converters available in most electronic shops). You then use the equivalent
output. This part of the specification isn’t usually well documented, so check
the shops return policy first.
Number of inputs: Count the devices you have, add to this the number of

devices you want to buy, and add two more for good measure! Once this limit
has been exceeded, you have no real choice but to buy a bigger switch box. You
can chain them, which is troublesome and lowers quality, or you can use a
separate EXT input on the TV for each switch box, which is equally annoying
but has fewer electronics in the signal chain.

The biggest omission on the entry-level switch boxes is the facility to switch between stereo audio
and 5.1 surround. Consequently, you will need a separate set of cables from the 5.1 output of the DVD
(controlling the 5.1 speakers) and the stereo output of the DVD connected to your switch box.
Splitting and Merging
Once you have the AV signal ready, you might want to split it so that the video part of the signal goes the
TV, while the audio makes its way into the line-input on a HiFi. There are two main ways of achieving
this. The first is the easy way and works if your TV has its own stereo-out sockets, since they can be
connected from the TV to the HiFi directly without a problem. The other way is to split the signal coming
out the switch box into two (or more) outputs—one for the TV and one for the HiFi. This approach
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means you won’t be able to use the HiFi to amplify any stations selected using the TV’s internal tuner,
but this can be rectified by watching the TV solely through a receiver (such as a cable tuner or digibox) or
VCR, which has been plugged into the switch box. This can be done in a variety of ways. The cheapest is
the use two Y-cables (aka Y-adapters), one each for the left and right audio signals. These provide two
identical outputs from one input and require no power. These work well when splitting audio signals but
can be less than satisfactory when used on video signals because of impedance problems. If the quality
isn’t good enough, then you need a more involved splitter box.
A splitter box acts like its Y-cable counterpart but usually has an amplifier in it to stop signal
degradation. This also allows it to provide more outputs for very little extra cost, allowing you to run a
separate pair of cables into the kitchen and dining room, say.
If neither of these is suitable, you can split the output after the amplifier stage by running multiple

speaker cables.
Wiring Looms
Wiring looms is where cables carry a powerful signal (pun intended!) to drive various passive speakers
around your house. Consequently we call this passive distribution. You should create one loom for each
area of the house where the same audio content is likely to be heard, because local control here is more
difficult (unless you get speakers with a volume control or want to hack one yourself). In a room layout
as shown in Figure 3-1, you have little privacy between the living room and the dining area, so these
would be on the same loom, as would the kitchen since you probably want to pop in and out of the
kitchen without missing the music or TV output. If an extension, such as a sun room or den, were added
to the rear of the house, on the other hand, it would be considered a separate area with a different
lifestyle purpose and would not be on the same loom. Instead, any music in there should be provided
over IP.


Figure 3-1. A standard downstairs plan
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The first component in a wiring loom is the main power amplifier, taking its input from the switch
box we covered previously. Normally, this will drive one set of speakers, although some amplifiers
provide extra outputs for additional sets. It’s rare to have more than two and even rarer to have more
than a couple of rooms on the same loom, so you don’t often need any more equipment.
In those cases where you need more outputs, you can add a speaker control box into the chain. This
takes a single speaker output and splits it into many. These additional speaker cables can be run into the
other rooms and wired directly into other speakers without the need for power. This is the main
advantage of this approach; namely, the cables are easier to run (the holes are smaller because there are
no bulky plugs on the end), and there’s no need for power sockets nearby, enabling you to add music to
the bathroom where media players would not be practical or possible.
■ Note Special waterproof speakers are necessary for bathroom use, which have sealed cones and baskets so

they can cope with water and humidity. Various models exist, including flush-mounting ones that can be placed in
the ceiling.
Provided you use a reasonable quality of speaker cable, the signal will not dissipate over the
distances involved.
■ Note If you have two outputs on your amplifier but want to control three sets of speakers, then connect the
control box to the second of the outputs and your primary speakers (on which you’re more likely to do critical
listening) on the first. There’s no point in adding a step in the chain if you don’t need to do so.
Wireless AV Distribution
Running cables is not difficult but should be done with care to avoid drilling through power cables,
water, and gas pipes. With this in mind, there are a few pieces of hardware now available, such as the AV
video senders you saw in Chapter 1, built to solely wirelessly distribute audio signals.
For the most part, they offer a solution of convenience, but landscape speakers, which are built to
exist outside and made to look like rocks (for example), provide the only practical solution. They must
also be powered from batteries.
Matrix Switchers
For most home applications, a standard switch box is enough to control your AV setup. If you have a Blu-
ray player or other high-definition equipment, you will generally plug it straight into the TV using HDMI
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because this eliminates all other components from the signal chain. And, alas, none of the reasonably
priced switch boxes I’ve seen support HDMI.
8

Furthermore, if you want to distribute two of your input devices (such as PVR or DVD) to two
different places, then you’ll find that you can’t, because the switch only provides a single output.
Both of these limitations can be overcome with matrix switchers. They have a broader range of
inputs (often including VGA) and can send the input signal from any one of (say) eight inputs to any (or
all) of the outputs, which often number four or more. This allows the most powerful AV control method

possible, with all your hardware being located in a single place and the results carried by cable to each
room in the house. Also, since this is professional-level equipment, it usually comes with a serial port,
making it easy for a computer to control it directly.
Utilizing a matrix switcher in your setup is a big step, not just financially. To make full use of the
device, you will need to keep your AV equipment in close proximity to the switcher. Furthermore, not
only will you have the usual mess of cables entering the switcher, but you’ll have an additional mess of
cables leaving it—one set to every room. And for the most part, matrix switchers are not small.
Consequently, it is impractical to have them in the living room. Instead, you need to consider a room or
a hidden cabinet into which the switcher and AV equipment can be placed. With the equipment now
hidden away, the purchase of an IR relay or gateway to retransmit IR signals to the devices inside the
cabinet is essential. It will be needed for the matrix switcher and may come as part of the package, so
buy it second!
The output connectors vary between matrix switchers. Some provide the output as an AV signal, like
S-Video or other domestic formats, making it very simple to connect other receivers into your home and
have it work. Others are intended for hotels and conference centers and encode each input into a
proprietary protocol so the output can be transmitted over Ethernet. This case requires an additional
receiver unit for each room, thus saving the effort of running specific AV cables around your house. And
because the data is traveling over your existing Cat5 cables, you can usually send the IR control data
back the same way, saving you on the IR relays that are so often necessary.
■ Note If the majority of your source media is stored on a hard drive, then you probably won’t need a matrix
switcher at all, since it can be transmitted by Cat5 to small Linux-based head units using software-streaming
solutions such as VLC.
For those evil geniuses living in an underground volcano, a matrix switcher provides a mission-
control room scenario for very little extra cost! After all, you can connect one set of outputs to a row of
small, cheap TV sets and watch multiple sources at the same time.


8
There are a few HDMI switch boxes now appearing on the market, but these contain only HDMI switching such as
the one shown at

They are
still hugely expensive, so realistically the choice now is either to have local processing of data or to distribute only a
standard-definition version of the picture around the house.
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Control
Having the ability to play music in every room is one thing. Being able to control from every room is
something else. This is the next step in the chain but one that is not always necessary. Imagine the house
layout shown in Figure 3-1. This needs no complex control systems since the living room is controlled
locally, and the kitchen audio stream is usually switched on when you start preparing dinner and
switched off once you’ve finished. Consequently, being forced to control the AV from the living room is
not an issue.
Nor is it an effort to wire several rooms together (for example, the master bedroom, bathroom, and
den) with a speaker control box and leave them on all the time. In this case, it is likely that although two
of the three rooms may be unoccupied for most of the day, when one of them is in use, it is at the
exclusion of the others, making it unnecessary to apply the cost or effort in providing separate controls
for each room.
Local Control
Being able to control the device (such as a speaker or stereo amplifier) from the device itself is the most
logical solution, and fortunately most head units provide this automatically. A local amplifier or set of
powered (active) speakers, for example, will have a volume control on its front and a means to change
the source input. Therefore, any distribution system using AV or Cat5 cables will have control built in.
To affect the volume of a passive speaker (maybe one fed from a remote speaker control box), you
need an attenuator placed in series with the speaker. For low-power solutions, it is possible to mount a
double logarithmic potentiometer directly into the speaker mountings. (You need logarithmic because
this is the way volume works, and you want double for stereo volume control.) This won’t give you
particularly good fidelity, since the two tracks inside the device won’t be well matched with each other
and some frequencies made be lost, but it will be cheap. For a better solution, there are custom

attenuators that come in a basic wall unit and provide a better-looking control mechanism, with
improved quality. If your speakers are not wall-mounted, then you will have to run an extra set of cables
either inside the wall cavity or in external tracks. Consequently, the cable runs from the speaker control
box to the switch and then to the speaker. It is better to consider this approach before laying other
cables. Apart from the bathroom (where such attenuators need to be waterproof), this method of control
is usually impractical and better served with active head units or no form of local control at all.
Remote-Control Methods
Your house will come alive with the sound of music. Until you’ve lived with music in every room, you
cannot underestimate the difference it makes. Being able to change the volume is nice, but not
necessary, because each album is normalized to be consistent within itself. However, if you’re
randomizing the tracks, then the volume can vary wildly, necessitating a local volume control. And if
you’re introducing such functionality, you’ll often want more involved local control to skip those
random tracks you don’t want to hear. Such functionality requires more hardware.
Direct Control
Standard HiFi equipment is invariably supplied with an IR remote, making it possible to place an IR
relay receiver in each room and line up its transmitter with the receiver eye on the device. Small
receivers can be mounted in-wall alongside, or instead of, a light switch and be powered by batteries.