What is the difference between rock & metal?
 

What is the difference between rock & metal?

They're different genres.

Metal tends to have a louder, heavier, harsh and massive distorted sound than your general Rock music.

There is a lot of metal that sounds like rock musically though, like power metal/hair metal bands, the latter often being considered a rock genre.

I think what separates metal from rock is the more abrasive themes, it's almost like punk in that it almost has an ideology attached to it. Some hair metal/nu metal bands for example are accepted by metalheads, while others are considered rock bands.

Personally, I just know metal when I hear it. I can't describe it perfectly, I can generalize that it's typically louder/faster than rock, but that's not always the case.

Not quite, metal is a sub-genre of rock and metal originates largely from blues rock and psychedelic rock. These influences were gradually faded out by the end of the 1970s and early 1980s. Also at this time what was considered heavy metal and hard rock, had very little difference in terms of which was louder and it came more down to subject themes. Since then though and largely with thrash and extreme metal, metal has largely become more abrasive and more diverse than it ever was.

Well, power metal isn't excactly Beatles

Neither is Poison or Def Leppard.

Hmm.. Couldn't you say that for most genres? I mean, what's the difference between jazz, blues, rock, funk, soul, and the train goes on? Metal is a sub-genre of rock. Metal closely resembles Hard Rock. Punk has roots in metal. Blues has roots in metal. Punk has similarly fast riffs as metal. Alternative rock can have harsh distorted guitars like metal. There must be a commonplace separating them? And I'm guessing they do it with the most common attributes.

The question is too general I suppose.

I agree, but I'd still consider them rock.

What could you say for most genres?

You're focusing too much on the distorted guitar thing. There's a very distinct difference between a punk riff and a metal riff. Metal riffing usually employs a lot of picking, whereas punk riffs are usually just strumming. Hardcore is different, but 99% of hardcore bands could easily be classified as metal bands as well.