Re: a:4 chord

[Brett Duncan]

Luc Saffre wrote:
> Can somebody explain what's the difference between printing "A^sus4" and
> "A^4"? I had only basic music education but am helping with publishing a
> songbook using Lilypond, and I thought that the difference is not
> important. But now I'm afraid I'm wrong and that I'll have to check some
> songs again. Is that right?

The short answer is, it depends on who you are talking to!

If you look at the Dolmetsch Online for example 
(http://www.dolmetsch.com/musictheory17.htm), you'll find there that C4 
means a C major triad with an added 4th (C-E-F-G). I know several jazz 
musos who interpret it exactly this way.

OTOH, others interpret C4 as a suspended 4th (C-F-G).

Just to add to the confusion, some rock guitarists use this notation to 
indicate an inversion of the classic "power" chord, which is really just 
 an interval of a 5th (e.g. the C5 power chord is just C-G). A C4 in 
this case is just an inversion of an F5 power chord, with just C-F.

Personally, I prefer to avoid the potential confusion by not using the 
notation C4 at all, and use Csus4 or Cadd4 to clear what I mean. (I 
don't have to myself  the power chords, since they don't get used that 
often in jazz ;-).

One other thing to be aware of - if you put C:4 into LP, the chord you 
get is C-E-F, which doesn't actually fit any of the above 
interpretations of "C4". So if you want the power chord, for example, 
you need to enter c:4^3 to remove the 3rd.

HTH,
Brett