Modulation

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What is it?

Modulation is a posh word to denote "going to a new key".

• Sometimes it's a large scale change to a piece, and there will be a double bar line and a new key signature that heralds a passage in a new key.
• Sometimes it's a temporary change and there will be some incidental sharps or flats (characteristic of the new, temporary key) that introduce a cadence in the new key, before the music returns to the "home key".

Typical modulations

Nothing is typical, of course, and some of the greatest composers have enjoyed parading their talent by weaving a melody that seamlessly takes the listener to a key that's totally unexpected - the musical equivalent of driving round a corner to see an unanticipated vista.

But expecting the expected will help you read more accurately and position the hands more appropriately.

Here are the most common modulations...

• From tonic to dominant (see my Degrees of the scale article) - "going to one more sharp/one less flat"
  Example - going from C (no sharps) to G (one sharp)
   
• From tonic to subdominant (or from dominant to tonic) - "going to one less sharp/one more flat"
  Example - going from A (3 sharps) to D (2 sharps)
   
• From relative major to relative minor (see my Key Signatures article) - "signature stays the same"
  Example - going from C to Am
   
• From relative minor to relative major - "signature stays the same"
  Example - going from Em to G

Playable examples

Here are some really cut-down examples so that guitarists of any ability can try out the common modulations...

From C to G An extra sharp appears
From A to D The "highest" sharp in the signature is removed
From C to Am The minor's leading note is sharpened
From Em to G The minor's leading note is naturalised