Trying to sell you a more expensive cable for a Free Sat box is indeed daft, but then again he "as a salesman" was only doing his job, but that does not give him the right to try and fob you off. I never use "standard" cables as I KNOW they make a difference. It's not a guess or imagination; in most cases it is obvious. Having said that, a given cable is subject to the variables like anything else in life. A good cable will be perceived as different by different people when connected between different equipment. This is of course all part of being unique both as humans and in the gear we choose to buy and the environments we use them in. I have a £330 Nordost Silver Shadow between my DVD player and processor. Now the debate about does it make £330 worth of difference is both academic and a waste of server space, but the difference for me is profound and welcome. With the DVD player being £3500 and the processor £4000 a £330 cable seems a little cheap. In comparison to an IXOS 105 or a Chord Chameleon the difference for me in my environment with my variables is staggering and nothing short of brilliant as the increase in enjoyment is great. Note I said enjoyment not sound quality. Sound quality is another variable and the experience will be different for everyone. Anyone and I mean anyone can hear for themselves that an analogue cable used as a digital interconnect is left way behind when compared to a £25 digital cable like the 105.
There is no question that a good few manufactures can fool buyers into believing a cable is better than another just by, for example, having a fancy looking plastic over braid. But a lot of money is spent on designing cables to achieve a certain level of signal transfer ability and it is this that is not understood by 99% of people on the street. Thus it is the salesman’s job to convince you otherwise, by demonstration. Without going mad and starting a forum riot, the two key factors that change cables performance are capacitance and speed. In an analogue interconnect capacitance plays a big part in how the cable will sound. Analogue audio circuits are packed with capacitors and many make up filters of one description or another. Inputs and outputs on equipment we can buy are made with very tolerant loading impedances and thus most cables will work perfectly normal for most people and no one would be the wiser. However, if some equipment was made with tight tolerances and thus demanded the use of a cable with a specific capacitance then you would be forced into buying that cable. Normal equipment can have the "loading" and thus our perceptions altered by using different cables. The changes can be very noticeable or nonexistent to most people.
Funny thing is some people are so against the thought that a cable changes the signature of a given piece of equipment that they will themselves into believing a change is impossible and therefore aren’t really interested in wanting to find out. Nevertheless changes are made and input/output circuits will behave differently usually within a group of frequencies. Hence the term dull, natural, bass heavy and bright cables. None of this is science fiction but actual fact. Analogue audio is very susceptible to these changes but it is not always discernable by the listener in their set of variables. Test equipment arguments are again a waste of time. So you really can fine tune equipment with different cables. But what's important to realise is that the best cables ,in price points we can afford, need not make an perceivable or beneficial difference unless, you can experiment with many types and more to the point have equipment can benefit from the changes.
Midi systems and all in ones are a case in point. You're lucky if they can relay the contents of a CD to you in a pleasant fashion let alone be tweakable by cables. Likewise you wouldn't expect someone to spent £330 on an interconnect for a £29.99 DVD player bought from ASDA. The difference could well be there but it doesn't turn it into a £400 DVD player, maybe a £100 model instead. In exactly the same way you wouldn't dare fit remoulds to an Enzo, cable choices are made in relation to the equipment you have or a specific need. Digital cables are not so effected by capacitance as far as my understanding goes. In the threads context HDMI cables cost more, the faster they are. When transferring data at massive speeds like HDMI cables can the shear amount of data at such a high frequency can cause a slow down. The slowing down of certain parts of the flow causes timing errors and other anomalies that decoding equipment can interpret as noise, and errors. The errors can then manifest themselves as blooming, pixel noise, colour imbalance, halos, edging etc. The higher the frequency you try to jam down a cable the more specialised the cable needs to be. Not necessarily the more expensive but the more unique to type the cable needs to be.
Using the wrong type of cable can be detremental to system performance too. Antenna systems cannot be tuned properly if the cable isn't 50Ω or 300Ω. Often the antenna will simply fail to work altogether. TV coax is not designed to work at the frequencies Satellite based systems do. You cannot drive large speakers with bell wire, as the cable cannot carry the current needed and so on. A good cable, not necessarily an expensive one is essential in this day and age. We now live in such noisy environments with fridges going on and off every hour, relays in thermostats sparking and sending out radio waves, power stations getting closer to urban areas, broadband, wireless routing etc that a good cable is needed just to convey the data we want at that moment, never mind how the data is perceived the other end.
In closing the whole purpose of HDTV etc is clarity, so push the limits as far as your budget will go, but don’t be ignorant in thinking there aren’t benefit to be made and improvements waiting to be freed, just don’t expect them to come for £10 or even in your current configuration if you spend £100 without experimentation and testing. If, like most, you can’t be bothered with all that then do yourself a favour and at least buy the next lead up, regardless of what it feeding. ARCAM has for many years been selling its equipment without leads in the box. The manufacturer could charge another £20 and chuck in garbage or something they themselves make and yield good profit from but they don’t They know that the system can be altered to accommodate most tastes and are happy to essentially give money away to a cable maker for your benefit.