I'm with Tim on the cheapo cables thing - unless you are a dog, you ain't gonna appreciate any extra frequencies.
Who said owt about "extra frequencies"?
It's a question of frequency "response" not audible range
and also signal degradation
You don't need to be a dog to notice either of those :|
Loudspeakers: Effects of amplifiers and cables - Part 4 | Audio DesignLine
If you say cables don't affect the sound of a system, you might as well say the choice of amp won't affect the sound, because it's all one big circuit at the end of the day!
Here are the results of a test into the effect of speaker cables on sound, taken from a presentation made tothe Reproduced Sound conference of the Institute of Acoustics.
The experiments were done by 2 Russian engineers, accompanied by the founder of Cerwin Vega (hardly "some bloke in his garage")
Loudspeakers: Effects of amplifiers and cables - Part 5 | Audio DesignLine
There's a lot to read (it's a proper scientific study) but here's an extract...
"However, when they replaced the 8 ohm resistive load with a passively crossed-over loudspeaker system, they were surprised to see the results as shown in Figure 6.8. With the more complex load, all the plots had changed. After changing the load to the low frequency loudspeaker, all the plots changed again, as shown in Figure 6.9. The distortion patterns were noticeably different, not only between the cables, but also between the input and output ends of each cable. The implication here is that the cables change the way that the complex load is seen by the amplifier. Voishvillo reported that upon seeing this, Czerwinski exclaimed "But they're only short cables!"
Another bit from the end of the chapter (before they move on to discuss the effects of splitting the frequency range... multi-amp setups and the like)
"As the evidence presented in this chapter has shown, loudspeaker cables seem to be sensitive to the equipment to which they are connected, and vice versa. Furthermore, the entire systems seem to be sensitive to their environment, at least in electromagnetic terms."
To sum up, more expensive cable does not guarantee "better" sound (whatever that means).
But I'm afraid anyone who claims speaker cables & interconnects won't have an effect on the sound of a HiFi system is just plain wrong.