Hardware Reference
In-Depth Information
The output connectors vary between matrix switchers. Some provide the output as an AV signal, such as 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 that 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.
N
If the majority of your source media is stored on a hard drive, then you probably won't need a matrix switcher
at all, as it can be transmitted by Cat5 to small Linux-based head units using software-streaming solutions such as VLC.
Note
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.
Control
Having the ability to play music in every room is one thing. Being able to
control
music from every room is something
else. This is the next step in the chain but one that is not always necessary. Look at the house layout in Figure
3-1
again. This needs no complex control systems because 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, as the two tracks inside
the device won't be well matched with each other and some frequencies made will 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.
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