Cables don't "improve" the sound quality. They can alter the signature and reduce the amount of distortion.

For a mere 5cm, I wouldn't waste money on expensive cables as the difference wouldn't be noticeable to my ears. But for longer cables, the characteristics of the sounds can be noticed.
How about we do a little meetup somewhere quiet? I can bring the cables with my headphones and a DAC/amp unit. But you have to bring a laptop because I run on desktop.

the extra 9 in 99.999 wont make any difference unless you have the 'golden ears' some claims to have, the cable will be fine if its comply cable manufacturing standard.

I suggest use canare cable, bang for the buck but don't buy from pcwork or jaben, they just selling it way too expensive.

Why not.. Just use the regular 60/40 solder, just make sure there is no cold join.. Flux is your friend

My location is Cyberjaya. I don't understand how cables alter the sound signature, probably have something to do with the material properties.

The impurities in the copper affect the flow of electron..

As a person who made a cable and tried it on my superlux 668b the signature definitely is different depending on cable. Canare gave my superlux more prominent female vocals which stood out more while stock cables made instruments stand out more.

When switching from cable to cable the sound change is instantly noticeable if you know the song well.

of course custom cable im unsure of because I don't have other cables, but the stock cable itself is good. If I wanted to hear more instrumentals i would use stock and if I want to hear vocals i will use the canare cable. It's all about what kind of signature you want what you want to hear and how it corresponds to your taste.

Yes custom cables from other people are expensive because your paying for materials and workmanship despite what people say, if you can make it yourself than no one will stop you. Audiophile stuff is very subjective lets just say there's no RIGHT answer. If someone spends 100USD and likes the change in sound than let them be. Some people dont hear the difference fine just dont buy the 100USD cable and go make a RM20 one instead.

Some people do hear the differences between expensive and non expensive cables but who are we to judge them since they are the ones hearing it, not everyone has the same hearing capabilities, everybody is different.

Cable makers like pcwork do a lot of tinkering trying out different cable types with different plugs with different headphones. Braiding, designing all of that hard work is done by them, than people go in and say "aiyah these stuff i also can make why so expensive", but the fact is that your just copying what you see inside you didnt take the time to test all the different types of cables and plugs not thinking about the hard work and passion that was put inside those cables.

You can see all the people who adore(not worship) PCWork because of his handywork, they are of really good quality and also looks wise they look really great.

prices of these cable can go very crazy can be due to the material cost as well, some cable makers tend to perform some treatment on their cable so that it could further improve the conductivity. Example: cryogenic treatment. So far all the cryo treated cables I tried seems to have rounder highs.

Different cable makers has their own way on making their cables, sound can be differ on how much solder amount you applied on each contact point and how many cable strand you used on each terminal, so I would say yeah, switching from one good custom cable to another might show differences, also, depends on your setup's sensitivity.