quick ? about Keys...

[4 stringed fury]

Is a song only bound to only one key at a time?

For example, if a song is in the key of G does the song have to remain in that key till song is over or can the song be in the key of G and at a later part be in the key of B or whatever?

[Jazz Ad]

You can change keys during the song. One of the simplest way and most common way to do it is transposition. For example you raise the whole harmony by one tone to increase tension in the song.

[pete honeyman]

Most songs change key (modulate) several times - they would be really boring otherwise. At it's simplest, as soon as a note that isn't in the key of G starts appearing, such as a D sharp, C sharp, G sharp, or any flatted note, the song has changed key.

[HaVIC5]

Some of the more complex tunes might change keys every bar (Giant Steps, Countdown), and 20th century classical pieces might not have any key center at all. Key's aren't sacred - music would be pretty boring if every song stayed in the key it started in.

[HaVIC5]

Originally Posted by pete honeyman

Most songs change key (modulate) several times - they would be really boring otherwise. At it's simplest, as soon as a note that isn't in the key of G starts appearing, such as a D sharp, C sharp, G sharp, or any flatted note, the song has changed key.

Not necessarily. You can have modal interchange and not change key, and secondary dominant patterns aren't necessarily a change of key either. If we're talking classical music, you also have that funny Neopolitan sixth chord - bII major - and that is still in the home key.

[Bassmickeyd]

The easist way to modulate to another key is to introduce the five cord of the new key then make the change.
Take a 12-bar in the key of G on the 12th bar(the turn-a-round) play F#7 instead of D7 now your in the key of B. Then at the 12-bar in the new key play Bb7 instead of F#7 and introduce the new key of Eb. Then at the 12-bar play D7 then you're back to the original key of G.
It's a simple exercise that works and it sounds like you doing something different than playing 36-bars in G.

[seanm]

Quite a few country songs change key. A key change can change the mood of a song. It can make a song sound sadder, for example.

A great example of a song with key changes is Johnny Cash's "Five Feet High and Rising". It changes key every verse.

But most rock/pop/country songs stay in one key.

[pete honeyman]

Originally Posted by HaVIC5

Not necessarily. You can have modal interchange and not change key, and secondary dominant patterns aren't necessarily a change of key either. If we're talking classical music, you also have that funny Neopolitan sixth chord - bII major - and that is still in the home key.

Absolutely, but that's a level of complexity that I don't think the poster was looking for at this stage.

[BassChuck]

check out Bobby Hebb's "Sunny". Same silly song in 4 different keys.

[mutedeity]

Originally Posted by pete honeyman

Most songs change key (modulate) several times - they would be really boring otherwise. At it's simplest, as soon as a note that isn't in the key of G starts appearing, such as a D sharp, C sharp, G sharp, or any flatted note, the song has changed key.

That isn't really true at all. "Key" is about where the centre of tonality is. A passing tone outside of the diatonic "key" does not modulate the tonal centre. You can still have an E7 resolving to Aminor and still be "in key".

To answer the OP, there is no reason why you have to stay within the framework of a "key" for the duration of an entire piece of music.

Oh, by the way the key of G has an F# in it.

[Martin Bormann]

Originally Posted by pete honeyman

Most songs change key (modulate) several times - they would be really boring otherwise. At it's simplest, as soon as a note that isn't in the key of G starts appearing, such as a D sharp, C sharp, G sharp, or any flatted note, the song has changed key.

Do you even know what a key change is? Because you're post here says you don't.