The Solo is the top manual. Its pipes are enclosed in a box like the Swell, and it contains a variety of stops for solo use. They range from delicately expressive flute and reed stops (51, 55-7) to the extraordinarily powerful battery of Chamade trumpets (58, 59), the pipes of which project horizontally from the front of the case.

Also based on this keyboard is the Echo Division – the stops hidden in Symphony Hall’s reverberation chamber. They are located behind the first level of doors on either side of the main instrument. Each side is separately enclosed in a shuttered box for expressive purposes (like the Swell and Solo). Right- and left-hand sides can be played together as one, or separately, each against the other. Each side has powerful reed stops (61, 62, 64, 66), and an expressive solo reed stop (63, 65). In addition, the right-hand division has the organ’s most ethereal stop, the distant and gently undulating Unda maris (‘waves of the sea’) (60).

49. Salicional 8’
50. Cor de nuit 8’
51. Traversflöte 8’
52. Céleste 8’
53. Viola 4’
54. Rohrflöte 4’
55. Waldflöte 2’
56. Baryton 16’
57. Clarinette 8’ Tremulant Chamade Trumpets
58. Trompette en chamade 8’
59. Trompette en chamade 4’

Sub-octave Chamade to Chamade
Chamade on Solo
Chamade on Great
Chamade on Positiv

Right-hand Echo Division (enclosed; inside reverberation chamber)
60. Unda maris I-II 8’
61. Trombone 16’
62. Trumpet 8’
63. French Horn 8’

Left-hand Echo Division (enclosed; inside reverberation chamber)
64. Tuba 8’
65. Cor anglais 8’
66. Tuba clarion 4’

Right Echo on Positiv
Left Echo on Great