The nomenclature of the crónán strings Γ & CC might indicate two tonic bass positions for C
mode tunes, one in téad leagaidh tuning and one in leithghléas.
The primacy of crónán Γ could implied by Bunting's use of the term 'íochtar' with crónán CC.
Such a primacy may be related to the primacy of G mode in some earlier period of Gaelic
music. The most popular mode in the Divine Office is G (a major mode) and Bunting
importantly describes fuáil bheag tuning as the 'key of G natural' rather than the key of C
major in his vocabulary in MS34 f58r. We could theorise a time when only téad leagaidh
tuning would be used, when G mode would be the most important major mode, making the
crónán Γ a very significant bass note.
This period would be ended with a time when C mode had become the most favoured major
mode, along with the arrival of retunings using F# (and perhaps C#) which would allow the
transposition of the Gaelic modes into new keys, making crónán CC the most significant
bass note in téad leagaidh tuning (all naturals), crónan Γ the most significant in leithghléas
(one sharp tuning), and perhaps DD the significant bass note in 'fuáil mhór' (two sharps
tuning). The leithghléas tuning seems to have become so standard that the key of G one
sharp seems to have been regarded by even harper Donnchadh Ó hAmhsaigh (Denis
Hempson) as the 'natural key' for the Gaelic harp.
It is of interest that Arthur O' Neill tells of one Peggy O' Neill who, it might be interpreted,
seems to have poorly placed all her planxties in 'C flat', perhaps a tuning of all naturals,
although this might just be a musical joke indicating a lack of basic tuning skills on her part.