See my previous comment...
I used to work on military hardware/software so have some idea about data transfer.

I must admit that a very poor cable could introduce cross-talk, and high impedance could slow down transmission rates on two-way systems, but you'd have to make a really shitty cable to notice on something as undemanding as HDMI.
(Kliper Filllets Getting noticed by twats on the internet since, Fri 31 Aug 2012, 8:43, 2 replies)

My very favourite audiophile piece of equipment
was a set of LEDs that you attached to your cables. They would blink on and off because they were sucking out the noisy electricity that caused hiss through your speakers and turned it into light. By magic. Or because I guess the LEDs just KNEW which bits of the electric were bad.
(Spleep Shit, or get off the internet., Fri 31 Aug 2012, 8:50, closed)

Maybe
The pretty lights distract you from listening to the music properly - so you can't hear the noise!
(Kliper Filllets Getting noticed by twats on the internet since, Fri 31 Aug 2012, 8:58, closed)

wow
I must see this. Link?
(tyrellsOwl, Fri 31 Aug 2012, 13:16, closed)

My favourite was a set of knobs for an electric guitar
that claimed to reduce noise and improve the sound in various unlikely ways.

It could be believable except that they weren't electronics, they were just the [normally plastic but in this case] wooden knobs that sit on top of the actual control.

£500.

I can't find them now but I did just come across this quote about another set, to give you some perspective: "they look amazing but are a tad on the pricey side. £35!"
(MrChimp previously Monsieur, Fri 31 Aug 2012, 20:14, closed)

This. Exactly this.
Xbox 360 is hooked to my telly with an HDMI lead I got from Poundland. The picture and sound quality are both amazing.
(Penguinbert killed Ken Dodd's dad's dog, Fri 31 Aug 2012, 19:25, closed)