“My system is not based on any keyboard temperament; rather, it displays the sounds found on unrestricted instruments like the cello, violin etc, that can play purely in tune…

G. P. Telemann, 'Neues musickalisches System' cited by Bruce Haynes, Beyond temperament: non-keyboard intonation in the 17th and 18th centuries, (EM, 1991).

 Let’s begin with some background: Despite more than 60 years of Historically Informed Performance (HIP), it is only recently that the “lost art” of playing the natural trumpet, in the clarino (high) register, in its original form has been addressed with any success. (Nowadays, “Baroque” trumpeters usually play with the assistance of nodal vent holes, invented in the 1950s. You can read about this and related matters at our website, www.barokensembledeswaen.nl.

Aside from its technical challenges, other difficulties in tuning occur when playing a historic trumpet in a “normal” HIP ensemble. This does not make sense, since the trumpet is one of the few instruments we are absolutely sure was played in this manner.

Current general practice is for the entire ensemble to try to play in the temperament chosen by the keyboard player. The most common temperament is named after the Italian Sig. Vallotti, which was first published by musicologists in the 20th century but somehow “miraculously” emerged in 1779, designed as a starting point for tuning a keyboard when playing solo repertoire that uses a large variety of keys (tonalities).

music.case.edu/duffin/Vallotti/default.html click on “Access the article”.

     

Vallotti himself would not have expected this, so why do people do so now?"

However, we play mainly German ensemble music from at least thirty years beforehand. It’s also impossible to set up a fretted instrument (such as a lute) satisfactorily in Vallotti, not to mention its awkwardness on bowed stringed instruments, winds and natural brass. Therefore, Sig. Vallotti himself would not have expected an orchestra to tune in this way, so why do people do so now?

De Swaen’s raison d’être is to do what we do as historically as possible (and sound good), so we went back to our research of original sources and found that a lot of literature refers to ratios of “pure” intervals, based on the harmonic series - the overtones that are present in almost all sound. When upper voices play harmonies in these ratios, something quite magical happens – it produces “combination” tones above and below, which belong to the same harmony and enrich the resonance of the ensemble because all voices are aligned. This gives more overall sound and greater definition in boomy acoustics, such as churches – probably why unaccompanied vocal ensembles revert naturally to this way of tuning.

The voice was regarded as the ideal to which instrumentalists should aspire. Therefore, as instrumental parts are "voices" and these instruments are able to adapt tuning according to harmonic function, that's what we do.

   

...more like friendly percussion than a dictator of harmony.

What’s this got to do with trumpets (and horns)? Well, in short, and their Royal importance/Divine symbolism aside, a natural brass instrument sounds only the notes in the harmonic series of its fundamental length - i.e., one arpeggio and one scale above that. A certain amount of adjustment is possible on some notes but in general, its tuning is, by definition, “pure”- hence the glorious, golden resonance of a well-honed brass section. Since we started using the “pure” system, playing natural brass with De Swaen has been a pleasure, so it makes sense.

Many critics would scream: “but not with Bach”. Why? Was his training so different from other composers of the time? There is no doubt that he was a genius who developed these influences further than anyone else. He wrote for natural brass instruments in the following keys: D, C, Bb, A, G, F & Eb. His father, uncle and (second) father-in-law were Stadtpfeiffers, so one can assume that he was familiar with the characteristics and symbolism of the instruments for which he wrote and also aware that no single 12-note temperament can accommodate such a wide variety of keys with any purity.

Why temperaments? A temperament is a “closed system” of necessary compromise. When a tonality changes, so does the tuning of several of its notes - for an instrument of “fixed” pitch to play in twelve major keys would require 55 notes per octave (hence why we refer to “micro-tonal tuning”). As you know, most keyboards have only twelve notes per octave, although many were built with more than that to address this issue. Therefore, decisions must be made in order to offset “purity” against practicality. A simplified basic choice is between the harmonic functions of sharps (thirds, or mi) and flats (4ths, or fa; roots & 5ths). The harpsichord/lute temperament we use is a 1/6th comma mean tone, which can be adjust between pieces of different tonalities. David has explained a bit about this, I hope.

   

....decline of keyboard continuo in orchestras...

So, who’s out of tune? “Well, those guys with only 12 notes per octave” would be a simplistic answer but the ingenious design of the instruments accounts for this: When a string is plucked on a lute or harpsichord, the pitch moves up and down (similar to the start of a note on a wind instrument) before decaying rapidly. So, especially in ensemble, a “fixed” pitch is not actually heard, making such instruments more like friendly percussion than a dictator of harmony. This might account for the decline of keyboard continuo in orchestras at about the same time as the fortepiano emerged: Being louder and having more sustain than a harpsichord, it would have interfered more with the rest of the orchestra, and so was promoted out of harm’s way to solo concertos. For a few years, even harpsichords were banned at the Paris opera for similar reasons.

Organists were recommended to play in a sympathetic way that complemented the ensemble- being careful with selection of notes, missing some out if necessary and to “…shorten every chord on the organ with both hands so that nothing disturbs the humming (Säuseln) of the violins”.

Schroeter, letter to JS Bach, circa 1740. (Synoptic): Dreyfuss: Bach’s Continuo Group.

("Säuseln” means the humming of resultant/combination tones). Sustained "pure" notes against tempered ones can create an interesting vibrato, similar to the natural (and to the "vox humana" register on old Italian organs that have two differently-tuned pipes for each note).

Next season, we are planning to do a special project with the Huygens- Fokker organ (designed in the late 17th century), at the Centre for Microtonal Music in Amsterdam, with 31 keys per octave.

There is nowhere near enough space here to cover this subject satisfactorily. We still haven’t mentioned musical training of the time, solmisation/solfege, monochords, “tonal geography”, affects (including the deliberate use of “blue” harmonies to emphasise the “bad”), open string tuning/sympathetic resonance, recorded examples of this system from the early 20th century and many other things but hopefully you will now have a little more insight into our intentions- for those “voices” that can, to tune purely in the tonality of a piece. After all, we do play tonal music.

Recommended further reading (or if you're still looking for Christmas presents):

How Equal Temperament Ruined Harmony (and why you should care).

By Ross W Duffin ISBN-10: 0393062279