Monday, 21 May 2012

Modulation, AM or FM?

Modulation, AM or FM? Many (many!) years ago , I was a telephone engineer in the UK, and went to college to learn my craft. One afternoon we learnt about radio and what was meant by AM and FM - Amplitude Modulation and Frequency Modulation. What I don't remember is the why and how of AM and FM, and to be honest I now leave it to the radio experts to ponder such things!
These days, modulation is to do with music for me. A lot of jazz is based on the use of 'standards' that is songs written by composers originally for the theatre, tin pan alley or the hit parade and then taken by us jazzers to make our own by improvising around these wonderful pieces.
Take 'How about you' for example, a great standard to jazz around. The lyrics of the first bit go:

I like New York in June,
how about you?
I like a Gershwin tune,
how about you?
I love a fireside
when a storm is due.
I like potato chips,
moonlight and motor trips,
how about you?
Let's say we're playing the piece in the key of F (one flat) a favourite for this piece.
Every thing goes alright, with straight forward chords until we come to "I like potato chips, moonlight and motor trips, how about you?"
On the face of it we see some strange chords for the key of F, until realise, that bit is in fact in a different key, the key of A (three sharps) in this case. What has happened is to the piece has modulated into a new key, for a bit.  As the piece goes on it goes back to the key of F and all is well again!
What the jazzer has to do in fact, is to recognise these temporary key changes, or modulations, because the jazzer will use different scales to solo (extemporise) around that modulated bit. The important thing to remember is that modulation is only a temporary change of key within the piece - and that's because the composer has written it in, and not a complete key change. If you changed the key to of the whole piece to G (one sharp) for example,the modulation as above  would now be in the key of B (5 sharps)!

Modulations within pieces make them sound really cool, as I sometimes think that pieces that don't modulate seem to go nowhere! The same of course is true in classical music, where modulations are all over the place!

So to get to grips with modulation and how it affects you as a jazzer, go on a Jazz Workshop and all will be revealed

Happy Jazzing

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