The Flemish harpsichord developed at about the same time as the Italian, but it is distinguished from its cousin by a very different design and sound. The Flemish instruments are physically stronger and esthetically rather roughly-made.
The Flemish tone is rounder and darker, with a strong fundamental and a fine speech; the decay is slow, and bass notes are emphasized. Among the Flemish makers, the most famous were members of the Ruckers family.
The Flemish instruments were taken as models by all the other schools in northern Europe, particularly in regard to dimensions.
The compass of a typical seventeenth-century instrument is C/E-c3, with one keyboard and two registers (8’4′) and a lute; a second keyboard, when provided, was used perhaps as an aid to transposition.
The functional second keyboard, a third (unison) register, and a larger compass (commonly FF-f3) were modifications introduced in eighteenth-century instruments or in Ruckers instruments later altered by French builders (the so-called “ravalement”).
Flemish instruments were usually painted, often with marbleized decoration, the soundboard decorated with flowers and birds, end-papers glued inside the case and in the key-well and on the lid. In the finest instruments, the inside of the lid was often decorated with an oil painting.