Cables and the quality of them is a very difficult topic. But I can assure quality differences can be big. The problem is that is impossible to judge by looking at them or trusting the advertising for that matter. I have experienced good quality cables at reasonable prices and relative marginal cables at astronomic prices. Really cheap digital cables may occasionally work correctly but only at short distances. The specifications (text) on the cable or box can be very misleading too. This for RCA, Speaker, HDMI and other media cables in general. For analog (RCA, Speakers) it is always better to get at least a decent one (whatever that is) and mistrust the one coming in the box. How to pick a good cable? Riding on practical experiences of many others is probably the safest way to go. You may also trust a certain (web)shop that does give good advice/reviews/positioning. Going to a real high-end Audio shop will work as well, as you will most likely get a real good cable there, but these may charge you an arm and a leg for it. I always get my cables from web-shops as the best price/performance is found there, regular shops and outlets typically charge far too much for often marginal quality cables. An example many years ago bought me a very long (1o m) quality HDMI cable when I got my first Onkyo Rceiver and needed to hook it up to my first media center being Windows XP on a tower PC. We were talking brand new HDMI 1.3 specs in those days. Some months ago I needed a long cable to hook up my Epson UHD 4k beamer to my media player and having this one still around just decided to use it for a quick connect. To my own surprise it worked flawless with 4K HDR and also at all 60 Hrz tests with Atmos sound. So I kept it as it fit exactly regarding length. A digital cable like HDMI works or it does not: - Having bandwidth problems you will see glitches and or artifacts specifically at moments of peak bandwidth utilization. - Having signal level problems you will get disruptions and re-connects. Moving a connector a bit should not cause any problems. Gold plated connections (provided they are present at both the chassis plus the cable) help here. Electric connectivity wise all HDMI cables are identical and backward/upward compatible. It is the shielding, EMP filters (those big bumps near the ends), wire gauge, wire twisting, copper quality etc that makes them pass a certain bandwidth and signal loss at specific distances. All this can be measured well using good lab equipment/meters but is not for the average home user. Distance is a crucially important factor for all cables and it is good practice to buy cables matching as close as possible your setup (looks much better too). Personally do swap occasionally perfect working cables for shorter ones (till even < one meter). The HDMI specification included on a cable indicates it matches (at least) the bandwidth required for that specific HDMI version at the given length. See the table attached for an indication of features coming with each HDMI version. As cables come at different lengths specifically shorter cables may support much higher bandwidths than derived from that qualification. The reverse should not be the case but it is easy enough to print anything on it. Buying a HDMI 2.1 certified cable should be pretty safe today despite specifically this brandnew standard being a bit vague on the exact upper limit it must pass. Getting a cable from a well-known brand may work too, but due to competition even these may have a wide range of different qualities on sale.
