The Grosvenor Temperament tuning was devised by Mark Lindley in conjunction with Joost de Boer and William Drake. The starting point was evidence that the mainstream English temperament of the Eighteenth century was fifth-comma meantone, using the syntonic comma. Although appropriate to the period of the original Grosvenor Chapel organ, it was accepted that for the new instrument, a milder ‘good’ temperament would need to be devised in order to avoid the ‘wolf’ interval. Thus, while retaining a meantone framework within the ‘naturals’, the ‘accidentals’ were tempered to allow access to a greater range of keys than a pure meantone would allow.
The following table shows the cent values of the scale:

Ab Eb Bb F C G D A E B F# C# G#
-2 0 +4 +8 +6 +4 +2 0 -2 -4 -4 -4 -2

 

The tempering of the Pythagorean fifths is:

Ab Eb Bb F C G D A E B F# C# G#
0 +1/12 +1/12 -1/6 -1/6 -1/6 -1/6 -1/6 -1/6 -1/12 -1/12 0

This temperament has been used in the following organs:
The Grosvenor Chapel, Mayfair, London
Jesus College Chapel, Oxford
House organ for Alfred Champniss
House organ for John Wellingham

More information about organ tuning