These names have been used to designate a Bourdon of small scale and soft tone, usually of 16' pitch, but sometimes (according to Irwin) of 8' pitch. Audsley reports that the Echo Bourdon differs widely from the Lieblich Gedeckt �on account of the different proportions and treatment of the mouths of its pipes, and, accordingly, in a special style of voicing.� He describes the tone of the Bourdonecho as �humming�, as opposed to the �covered� tone of the Lieblich Gedeckt. He recommends a wind pressure of 1 1/2" to 2 1/2", not to exceed 3", and that the pipes be made of oak or maple, �finished as thin as conditions will permit�. Locher and Wedgwood state that this stop is sometimes labelled simply Echo, a name which has been used for other stops.
Osiris contains about 20 examples of Echo Bourdon and Echo Bass, all at 16' except for one at 8' pitch. No examples of Bordonecho or Bourdonecho are known. Contributions welcome.