Re: Discrepancy in documentation,

[Carl D. Sorensen]

On 12/16/08 6:55 AM, "Simon Bailey" <address@hidden> wrote:

> hi,
> 
> On Dec 15, 2008, at 8:48 PM, Trevor Daniels wrote:
>> I've fixed the original error identified by David, added the
>> default Dominant thirteenth, and replaced some TODOs with what
>> I hope are correct chord descriptions.  On this latter point
>> could you please check I've done this correctly, as my knowledge
>> of interval naming conventions is not as reliable as I'd like.
>> The changes should appear on the kainhofer server on Tuesday.
> 
> 
> minor nitpick, which is probably my fault:
> 
> we have a half-diminished seventh with the modifier "dim5m7" and a
> minor-major seventh with the modifier "maj7m5". i think that may be a
> bit confusing.
> 

Constructs with two modifiers are not supported by LilyPond.  The rule is
that you get one modifier, then the rest of the pitches are supposed to be
adjusted individually. (This is not described clearly in the docs, so I
need to correct it.  I will add it to the known issues.)

So the half-diminished seventh should not be written as c:dim5m7.  Instead,
it should be written as c:m7.5-.


> but just while testing, i found out that the order of the modifier
> constructs is important. this is even more confusing ­ at least to me.
> (either that or i need more coffee). is there really a difference
> between a minor triad with added major 7th or a major 7th with a minor
> triad?

In LilyPond chord mode, yes.  You choose the type of the chord with a
modifier (e.g. maj7, dim5).  The modifier is unique in that it adjusts all
the pitches of the chord as necessary.  Once the type of chord is chosen,
all other modifications come in the form of added and removed pitches.

The chord parser for LilyPond works by creating the root, then using the
modifier to adjust pitches, then adding, removing, and altering steps to
further adjust pitches.  The known issues section of alludes to this, in a
cryptic form (it mentions that only the last occurrence of an added/altered
step is kept).

> 
> \chordmode {
> c1:maj7m5 c:m5maj7 c:dim5m7 c:m7dim5
> }

The correct usage should be
\chordmode {
  c1:maj7.5- c:m7.5-
}

Note that each has only one modifier, and the other changes are made with
an individually altered step.

Carl