Not sure what you mean by 'kerrrang', but if you mean really hit or pluck or strum the chord loud, then changing to a harder gauge set of strings might help.
Electric and steel string gauges are usually referred to as 'Extra Light, Super Light, Light, Medium, Heavy' etc, but nylon classical strings are sometimes also called 'Hard Tension' or 'Normal Tension' etc.
If the strings you have now are the ones that came with your guitar then they're probably Normal Tension. I tend to go with Normal because I don't like to have to press down that hard, lol, but when I was studying a bit years ago, my teacher suggested Extra Hard. It took awhile and I got used to it and was able to play harder without buzzes. Thing is though, the harder tension strings produce more volume anyway, so you can play just about the same and the guitar will project more volume.
Anyhow, here's a link to an online string place; I don't know if they'll ship to where you live, but you can use it as a reference point for various brands and types:
http://www.juststrings.com/classicalguitar.html
If that still doesn't fix the problem, then you might see if you can find a luthier to install a slightly higher saddle in the bridge so the strings are all higher from the frets. You'd have to weigh if a repair would be worth doing to your present guitar, or if it would be better to find yourself another guitar.
Lots can be done with a proper action-setup though, and harder strings.
Best regards.
