what is the difference between good and bad music

my friend says rap is bad music. another friend says mahler is a terrible composer.

is it all subjective, i.e., a matter of opinion ? or are there standards which can distinguish good from bad music, however one defines these terms ?

if there are standards, can one specify them or refer me to a source ?
Its amazing how many of you guys seem to actually listen to music and care whether or not its "good or bad". Hell, I thought this hobby was all about listening to trains, planes, and cannon shots.

Maybe, for the more advanced musicphiles amoungt us we need a modern 1812 Overture with Napoleon leaving Russia on a train as jets roar overhead and the Russians are firing their cannons at him!. Go figure - Music (for the masses). I'm amazed! We might even get it on multi-channel DVD so even if you're deaf you can get the picture and feel the vibrations.

Reminds me of Professor Johnson's old LP "Amazing Sound Show" (or something like that). They captured an African drumming group beating up a storm. Absolutely loved it!! Drove the wife and kids out of the house! Ask them about bad 'music'. :-)
Lrsky, there is one composer in "classical form"(outdated term, as each composer is very different) that strikes me as one that many of you R&R/blues, maybe even jazz fans may find interesting. Alfred Schnittke. I'm not saying you will like his music, nut it surely is quite unique among all the composers of the 20th century. I have almost everything he wrote and would be difficult to put any of his works in a order of favs.
I guess if I could recommend one, it would be his Concerto Grosso4/Sym5. The work goes by that title, as it is at the same time, a concerto grossso and a sym. Jarvi/Gothenburg/BIS. It was my intro to Schnittke one night at Tulane's ML, 1 month before Katrina hit, After settling in Baton Rouge I made an all out effort to collect all Schnittke. Have not been dissapointed.
Maybe when some of you are ready to make atransition into classical, that might be a good place to start.
I also love Allan Pettersson quite alot. Syms 2-11,13-15.
Both late 20th century.
If you don't care for Schinntke's CG 4 and Pettersson's sym 7, there is no need to go further into either composer.
But don;t toss the cds , wait another 5 or so yrs and try em again. Maybe something will click.
I left R&R late 70's.
The classical music forum is going through some ever needed changes, however some are violently resisting these changes, in hopes of maintaining The Institution.
Now that my system sounds better than ever, I listen to all kinds of "bad music" and love it! Perhaps all music is good if you allow yourself to get connected and hear it right, but then again...
hi bartokfan:

one does not know anything. one hears music and experiences it as good or bad. knowledge has nothing to do with it.

the assessment of genius is slo subjective. there are no standards of quality only opinion.

if a standard is devised, another standard will compete with it and there will always bedisagreement among serious listeners as to what good and bad is.

i believe the question of quality applies to evrything--art, wine, food, books, movies etc.

its all subjective if you like it its good, if you don't its bad.

it's a philosophical argument with no conclusion.

knowledge is based upon deduction from principles, axioms and definitions, it follows from a premise.

with respect to music, there are no premises as there are in mathematics, only opinions.

Albert: if you are open to Stockhausen, you might try to get your hands on Kim Cascone's 'Blue Cube' or 'Cathode Flower' - very cool computer-generated music by an associate of Angelo Badalamenti (Twin Peaks) or Jon Wall's 'Fractuur' or 'Alterstill' - music constructed of samples of 20th century composers (which doesn't sound sampled at all; it sounds composed and seamless)

I've added those to my list of musical considerations, thank you.