# The puzzle of keys/scales/modes...



## owildwestwind (Aug 16, 2010)

As a novice in music theory, i am puzzled by this, for example: 

Bach's 1st prelude from the well-tempered clavier is in C major.

Transposed by 1 tone, this piece is now in D major.
The "C" is changed to "D", but the mode of m a j o r remains unchaged.

So, to my mind, there is nothing intrinsic, nothing fundamental that
ties this piece to "C". The piece is just in major mode, and not in minor.

My question is: Am i right or wrong? 
Except for the average pitch of the sound,
except for the high or low tuning of the various instruments,
is there a real difference between C major and D major, 
or between any two major keys?


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## SonataSonataSonata (Sep 14, 2010)

In Baroque music, the key of a composition was extremely important in relation to the mood and feeling the composer wanted to get across in a piece of music. This could also influence tempo, as tempo markings were used but very rarely, as the performer was expected to know enough about the "rules" so that tempo markings weren't necessary (but that's another topic). So, yes, the first Prelude being in C and not D is pretty significant.

I haven't had time to study this entire page, but you get the idea:

http://www.wmich.edu/mus-theo/courses/keys.html


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## emiellucifuge (May 26, 2009)

Its a tricky question. Composers have, and do intend certain keys or tonalities to convey a certain atmosphere or feeling. In practice it is unlikely that the majority of listeners could discern the difference without a reference tone. 

More generally playing a dmajor scale directly after a cmaj scale would reveal differences.


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## gdfo (Sep 30, 2010)

Another factor is that the actual pitch of the Key has changed since Bachs time. The key of C in his time would have been lower.


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## AmateurComposer (Sep 13, 2009)

owildwestwind said:


> As a novice in music theory, i am puzzled by this, for example:
> 
> Bach's 1st prelude from the well-tempered clavier is in C major.
> 
> ...


The timber of an acoustic instrument is not the same for all pitches within its range. A composer might select a specific key according to the desired timber.


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## Delicious Manager (Jul 16, 2008)

In our world of 'equal temperament', it's hard to grasp the individual character of the various keys. Today, the modern octave is equally divided into 12 semitones. It was not always thus. While the piano sounds 'in tune' to us, it is actually very much a compromise tuning which divides the octave into 12 even semitones. This enables pieces to be played in any key with equally satisfactory results. However, to get truly accurate tuning according to the rules of physics one finds that, because of tiny intonation differences in different keys, one cannot play beyond 3 sharps or flats before noticing that notes start to sound quite out of tune. By the time you get to keys like B major and D-flat major, things start to sound very odd indeed.

You have also mentioned pitch. The pitch of 'A' was not standardised until the 19th century and every musical centre had its own pitch system (this is different from temperament). Today, for modern period-instrument performances, a compromise pitch of A=415 is used, which sounds approximately a semitone lower than today's pitch where A=440.


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