Let me start off with a bit of background. I've always been a keen fan of audio-visual solutions, being a sucker for the latest big television or surround sound system. When we recently bought a new house, some begging and grovelling to my better half resulted in me being allowed to rip up all the floor boards and install structured category 6 cabling throughout. This took all the more grovelling, because when I say "new" house, I mean exactly that. This was a newly built house in immaculate condition and I managed to get permission from the wife to rip it to pieces the same day we took possession of it! I am pleased to say it all went back together again in one piece, none the worse for wear.
One of my main reasons for the structured cabling was to run HDMI television signals throughout the house. Having five children, each of whom wanted Sky HD television in their room was turning into a big ask. As any parent will know, once one of the children has got something, they all want it. (Maybe allowing one of them to have Sky HD television was not such the good idea as it seemed at the time!)
I decided to install all my Sky boxes in a communications cabinet in my study. This way, it was easier to control and distribute the HDMI signals throughout the house. I did not want to be moving Sky boxes from room to room and having to work out how to get the satellite feed into these new locations. Having category 6 running throughout the house meant that a television would simply need to be situated near to a category 6 outlet and it could be patched into a satellite receiver in the communications cabinet.
I opted for an HDMI distribution matrix as my final solution. These devices allow signals to be routed from a number of source inputs to a number of destination outputs in virtually any combination. For example, one Sky box could be distributing HDMI to two different televisions. The watcher of one of these televisions could then opt to watch an entirely different Sky box. One big plus side of this flexibility is it cuts down on the quantity of Sky boxes that are necessary to complete the job. Obviously each Sky box adds monthly overhead to the system which is something I was trying to avoid. I decided on 4 Sky boxes for my final system, which means that a maximum of 4 separate channels can be watched throughout the house at any one time. Bearing in mind that several televisions are likely to not be in use at any one time, this seemed like a good compromise.
I needed eight different outputs from my matrix to serve all the televisions in the house. This is where the main point of this article comes in. 4 x 8 matrices are prohibitively expensive (4 x 8 means; 4 inputs, 8 outputs). There is a budget supplier of matrices with a 4 x 4 offering which is less than a quarter of the price of an equivalent 4 x 8 matrix, but obviously this would not meet my needs. However I came up with a solution where I purchased two of these 4 x 4 matrices and joined them together in cunning ways to achieve my goal.
The full solution is too complex to cover in every detail here so I will give a brief explanation. To make a 4 x 8 matrix out of two budget 4 x 4 matrices, you need to split the output from your 4 sources (in my case, 4 Sky HD boxes) using HDMI splitters. The two outputs from these splitters you then feed into an input on each of the matrices. This gives you a four-input solution but this can then be distributed to eight locations via the four outputs on each matrix.
In summary, matrices with more than four outputs are still in the domain of the expensive audio-visual system. Although budget matrices are now being produced, these tend to only have a maximum number of four outputs. With some clever use of external devices, the constraints of these matrices can be bypassed and many different combinations are possible.