So if you heard Bach's IVth played with a varied rythm, tempo or form, would you consider it a different piece of music? Or someone attempting to use someone else's work to make something new?
Bach's fourth what?
What I'm saying is that I can take a piece by a previous composer and make it completely unidentifiable by altering its rhythm, tempo, and form...it's really quite easy to do. Pitch material has nothing to do with what makes a piece of music familiar to the ear. This is evidenced by the fact that most of us do not have perfect pitch, yet can identify Beethoven's 5th.
Most importantly...changing the form would completely alter the piece into something remarkably different, the changing of form requires that the material be drastically altered (including the necessary deletion, addition, or restructuring of new material)...remember form determines underlying harmonic structure, shape, development, and process of a motive or melody. Just so we don't get sidetracked, remember my point is that there are infinite varieties of form, which provides us with another of many reasons why we aren't "repeating" music from the past.
More specifically, yes, it is quite possible to change ANY piece of music into a completely different sounding piece by altering the rhythmic properties of said piece. There are an awful LOT of serial pieces that use the same row and are not identifiably similar.
I beg your pardon?
What I was saying here is that if you were talking about 20th century orchestral works than it's likely that the reason you feel that way is because you don't know how to "hear" them...I'm not saying whether this is the case or not, but the general public doesn't tend to enjoy a lot of pitch-collection based music purely because their ears are attuned to the standard tonal V-I idiom, and they don't know what to listen for...which in turn makes it seem kind of rambling and pointless...if not horribly noisy.