Re: Key signatures in modes other than Ionian & Aeolian

[Erik Ronström]

>> Even if my opinion may differ from the general opinion here, I think that in
>> popular music, one would use standard D major key signature.
>> Reason: Two sharps clearly show D major tonic and the characteristic mixo
>> tone C (flat seventh) stands out in the sheet music by the accidental used.

> I very much agree. In my impression, nowadays most musicians (save medieval 
> or Renaissance music specialists and maybe Jazz musicians) tend to only 
> differentiate between "major-like" and "minor-like" scales/keys

Another exception is the pretty large and vivid community of Irish/Celtic 
traditional music, where key signatures usually written corresponding to the 
actual mode (so e.g. a tune in D mixolydian would be written with only one 
sharp). This makes sense as the music is (for the most part) strictly modal and 
diatonic.

Many musicians in this genre use abc notation rather than sheet music, and in 
abc, mode is (almost) always defined explicitly:
http://abcnotation.com/wiki/abc:standard:v2.1#kkey

Erik