Before you learn the Baroque flute, it would be wise to read some of the treatises by Quantz, Hotteterre, Tromlitz, and et cetera, to be able to make informed musical decisions when it comes to playing Baroque music. I’ve summarised a few key points about Baroque performance practise here, but it is obviously not a definitive guide and I strongly encourage you to continue to do your own research on the topic. You can consult the reading list for a variety of reliable sources on the matter.
Our modern flutes create a lovely homogeneity of sound: every note, in every key (except for a few exceptions like the dreaded middle C♯) will sound reliably the same each and every time we play it. Thus, creating colour and personality in music can be a bit more difficult. This is not so with wooden one-keyed flutes! The colour of each key is built into the flute: cross-fingered notes, by their very nature (sharing a hole with the note above so the sound column is split) sound more hollow and haunting, and you’re far more likely to come across them in minor key signatures; whereas keys like D and G are very strong and regal and much more bright. Whilst playing the Baroque flute, do not try and “better” the tone of these cross-fingered notes. Embrace them for what they are, and realise that they’re meant to sound that way, and the music was written with that sound in mind.
On the modern flute, vibrato is non-negotiable. You will be hard-pressed to find a flautist who leaves out vibrato, and will in fact have more luck finding players who put vibrato on every quaver they come across. Vibrato adds a richness to our sound and can completely change the colour and feel of a note or piece. In Baroque music, however, vibrato is usually only added on long tones that provide an opportunity for increased tension and a dynamic swell. This will most often be added towards the end of the note and with the finger as opposed to the breath, which is otherwise known as a flattement. You lightly trill the rim of a finger hole to create waves in the sound. Different finger holes will create slightly different flattement sounds, so do experiment with each note.
Modern flutes are made so that we shouldn’t be able to distinguish between a di or ti or ki sound—remember, homogeneity is what Boehm was going for! On a Baroque flute though, its simple design allows for tonguing styles to really be heard, and these different styles can emphasise or de-emphasise the contours and direction of a musical line in Baroque music. The type of music and the rhythms it contains will help you determine which style of tonguing to use. Quantz wrote extensively on tonguing syllables, but I’ll provide a bit of a summary:
A French term meaning rhythmic inequality, notes inégales is directly related to the tonguing styles described above. Notes, especially in scalar passages, can be lengthened or shortened depending on the character, meter, and tempo of any given movement. For example, a passage of straight quavers may be changed to a hardly-perceptible quaver/semi-quaver triplet passage in an allemande; this same straight quaver rhythm could be played as double-dotted quaver/semi-demi quaver passage in a regal overture.
Whereas, for example, composers of Classical and Impressionistic music left very clear instructions and marking for what they wanted the performer to do, Baroque music allows a large amount of freedom. Facsimiles or Barenreiter editions of music often provide little in terms of articulations, dynamics, and ornamentations, leaving it up to the performer to make an informed decision on what to do (a note: this means it is necessary to practice or perform off of the accompaniment, to make sure you have a knowledge of the bass harmony). Quantz was an advocate of tastefulness and simplicity in ornamentation. When you are first learning to ornament, a good rule to follow is to let the mood of the piece guide your decisions: trills are great for lively pieces, and appoggiaturas for gentle ones. Ornaments include, but aren’t limited to:
These ornaments will help to create sought-after dissonance within pieces, and can add a great deal of substance to an otherwise bare skeleton.