

The Baroque sound ideal is a florid treble over a solid bass with inconsequential interior filler.
Most Baroque music has a "horizontal" conception: the emphasis is on the voices moving across time, not on a series of harmonies (a "vertical" conception).
The printed page, during this period, served only as a reminder and a source for the melody and bass lines because musicians knew the style well since they were immersed in it every day. Therefore, what is -printed- is only a skeleton upon which the performer is expected to embroider (or even to show off). The performer, therefore, was expected to use the composer's printed ideas only as a jumping-off place. Often the performer -was- the composer; we know Handel was quite famous for improvising at the organ during intermission of his choral/operatic works and that in Bach's day he was known more as an organ performer and organ tester, than a composer.
Baroque music is encrusted with ornaments. Often only the first one is printed; the performer is expected to ornament repetitions of the motif (or fragment) in the same way even if they are not marked. This runs contrary to the modern idea of playing only what is on the printed page.
Another important point of Baroque performance practice is that the pieces were played on whatever instrument was available. Mostly, this was music to be played in one's home (cf Telemann's "Tafelmusik," or table music: music to be played en famille). Only a prince could afford a variety of instruments, and most families would be considered well-found if they had a keyboard, a violin, -and- a flute or recorder. If you visited friends or family, you packed your instrument as well as your clothing and looked forward to a lively evening or two of music-making and discovering how the musical instruments present might be deployed in the scores the family had or that you had brought along. Go to the record store (not onerous duty, I know!) and see how many different "orchestrations" you can find of Bach's "Art of Fugue" for an example of "play whatever instrument's available."
Baroque music generally has no tempo indications. For those pieces that do, bear in mind two things. (1) Tempi were somewhat slower in the Baroque than for a modern performance. Thus a presto by Scarlatti is allegro or perhaps vivace today; at a presto tempo, this music played on the harpsichord would sound like someone rattling a can of nails; played on the modern piano it would be even less successful. (2) Baroque tempo indications, when present, tend to be more of a style or character indication, rather than a speed recommendation. Sometimes the time signature does indicate speed. For example something in cut time (a C with a slash through it, which my computer won't let me do) indicated that the half-note got the beat. Beethoven's Pathétique uses the same device (that's how you can have a half-note that's marked staccato; the half-note is actually the basic unit of beat).
For a dynamic change to forte, the harpsichord player added another set of strings, fleshed out chords with added roots and fifths, rolled chords, and added ornamentation.
For piano passages, the player reduced the strings to one set, and if he were already playing on one set, he'd thin the texture by omitting notes in the interior voices or even play only the soprano and bass lines or perhaps even bass line alone. I am speaking here about basso continuo performance practices on the harpsichord. A solo piece would be dealt with differently; in fact, it would be written differently, as the composer would have the harpsichord's special characteristics and the type of music he was writing in mind during composition.
Because the instrument could not sustain notes for very long, impression of a sustained tone: long trill, alternating octave notes (known as a Murky bass), rolled chords, and restriking a note (especially in an octave notation: the upper note might be restruck rather than tied into the second measure and the lower note restruck for the third measure, or the reverse at the discretion of the player).
Lack of dynamics arising from the amount of power brought to bear on the keyboard was more than compensated by making the texture of each voice different (articulation). This loud-then-soft approach to dynamics is called terraced dynamics. We still see it in the "echo device" used by Mozart, Haydn, and other classic period composers.
It is said that the harpsichord is "an instrument of artifice." This is not meant in any kind of derogatory way but only that certain musical effects must be elicited from an instrument which is physically incapable of producing them.
The organ was available in churches but not commonly in homes. The organ had the ability to increase the amount of sound (through accretion of additional ranks of pipes) and could play sustained notes. For home playing of organ literature, there existed a pedal harpsichord.
The clavichord was used throughout the Baroque and Classical periods, fading about the time of Beethoven's middle and late periods. It has a dynamic range of p to ppp and is quite sensitive to touch. It was greatly favored as a practice instrument (Bach and Mozart praised it highly) but was unworkable as a basso continuo keyboard. The clavichord is the only keyboard instrument capable of vibrato (called Bebung).
The virginal, much associated with England (especially the Tudor family) and Italy (where it was often of much lighter construction and was hung on the wall when not being played), was not often found in Germany. (The first hint: how much German virginal music do you find? I don't think I've ever seen anything.)
The fortepiano (with knee levers instead of pedals to lift the dampers off the strings) was in relatively-common use during the style galant period (the Bach sons). Mozart, Haydn, and Beethoven early in his career favored the fortepiano. (Papa Bach reputedly disliked the fortepiano - - and there is no piano music left by him.) The semi-modern piano (with pedals) came into common use roughly during Beethoven's middle and late periods.
Plan to devote at least one half-hour lesson to talking about articulation and the "rules for lifts in Bach" and basic ornaments. Bach's music cannot be introduced in the last 10 minutes of a lesson!
Editions are important. I prefer an Urtext. For an inexpensive edition, try Kalmus (edited by Hans Bischoff) and paint out all the f, p, cres., descres., tempo designations, staccato dots, accents, and other markings. If what is printed in your edition "seems" incorrect, trust your intuition and paint it out.
Lifts are used on the following circumstances:
Let us use one of the two-part inventions as an example. One voice will be legato and the other what I call "detached."
Somewhat akin to lifts are what I called detached notes. These are part-way between legato and staccato. If you play a harpsichord, you will see that the instrument almost does this automatically for you.
What the material is determines whether it is played legato or detached.
You may wish to read my file about playing Bach on the modern piano. I also have written on learning/teaching Bach's imitative works.
copyright 1997-2003, Martha Beth Lewis, Ph.D.
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