As has been stated, the woodwinds are divided into homogeneous groupings (non-reeds, single reeds, and double reeds), with each division having instruments that are constructed in differing ranges approximating the tonal ranges of the human voice. With this in mind, it is possible to consider the practical over-all tonal range of each separate group in terms of its high, medium, and low playing compass. This kind of instrumental thinking helps to determine the best playing ranges for each instrument within the various groups. Several preliminary exercises are necessary before instrumental thinking of this kind can be practiced with assurance. Orchestration, as an art, recognizes the necessity for blended timbres, as well as their functional positions in the texture of good part writing. The uniformity of timbres, as found in the string section, does not exist in the wind section, which is one of mixed timbres. Therefore, the orchestrator must be constantly alert for these color differences so that a proper balance of timbres can be achieved. It should also be remembered that these very timbre differences can give distinctive tonal definition to any voice in all part writing. By scoring America in its usual four-part harmonization, some basic observations can be made resulting from the juxtaposition of different timbres. The common practice of giving the highest part to a flute and assigning the other parts in the order of their appearance on the score page produces the following result.
The weakness of this scoring lies in the poor tonal distribution of the soprano and alto parts. Whenever mixed timbres occur, care must be taken to assure clear tonal definition of the melodic line. In Example W-lOa, the low flute and the lower oboe cannot give this clarity. The stronger oboe timbre would dominate the flute in this register.
Two alternatives are possible in order to adjust this poor tonal balance. The first and most obvious one would be to invert the flute and oboe parts so that the latter would then be playing the soprano part. The second and more effective alternative calls for rearranging the voice parts in open position without changing the tessitura of the bass part. This can be accomplished by raising the melody an octave and inverting the alto and tenor parts. The new setting will give greater clarity and resonance to each part and also provide better playing tessituras for each instrument.
With the flute above the staff for the complete melody, the part will have the right tonal strength to carry well in the open-position progressions. There is also better voice leading in the two inside parts and a larger spread is provided between the flute and oboe parts.
A comparative analysis of these two settings of America offers rather conclusive proof of the need for understanding the importance of chord spacing, especially when mixed timbres are involved. Because each of the four instruments has special and varying tonal characteristics, each must be placed in its best playing range with spacings determined by the timbres of the adjacent instruments.
Scoring for wood-winds in pairs necessitates the expansion of fourvoice chorals by the addition of harmonic fillers and octave doublings. If the new eight-voice arrangement is given to the wood-winds in their normal order (high to low), the setting would be as follows:
The following deductions can be made from the foregoing example: (1) Single stems for two parts on the same staff may be used providing both parts have the same rhythmic patterns. (2) The first flute and the second oboe have the melody in octaves. (3) The octave-bassoon part is desirable as a support to the upper six voices. (4) The instrumental timbres have not been overlapped.
The next setting shows an interlocking of timbres in the oboe and clarinet parts. This device is useful inasmuch as it tends to blend the affected parts by neutralizing their identities as blocked sonorities. Note: Practically all tutti woodwind chords use this arrangement whenever feasible; the deciding factor is always that of tonal range spread. The better blending of voices that is achieved by this method makes it preferable to the former example.
A final wood wind setting of America calls for a voice structure of twelve parts. It will be noted that the oboe and clarinet parts show an overlapping, as in the previous example, but that greater freedom of voice leading in these two parts is now possible because of the greater number of total voices. The importance of good voice leading cannot be overstressed in dealing with instruments of varying timbres, since their equally varying tonal intensities require the utmost care in arranging them so that they will sound well in each division of the wind section. Wood wind parts should not be arbitrarily arranged according to blockedchord progressions. Rather, they should be arranged so that each instrument of the section moves as an independent voice — yet always in conjunction with and regulated by the voice leading of the other instruments of the section.