Panning, also called Seating is a crucial concept that has to be taken seriously in the orchestration process. There have been many different ideas and ways of positioning the players, but we will cover the basic classical ways of doing it. If you are not planning to create a real orchestra, but only a digital one, you should still read this part, because track panning and reverb is directly connected to the seating.
To make it short and sweet I will use images like the one above. The red color indicates the positioning of the brass instruments used in the classical symphonic orchestra.
It is is very crucial to position the percussionists in the back (or make the percussion track reverbed or panned far away) to let the sound get the power while travelling and resonating from the back of the hall.
During the history there have been literary hundreds of ways of placement for string instruments. But this one has proven itself to be one the most efficient ones.
It is also nice to place the woodwinds a bit further in the back so the sound can grow in power and add that extra punch, just like the percussion.
2.1 Melody in Violins
Usually the if the melody is in the higher registers (alto-soprano or higher) the most suitable instrument for it is the violin. And since there are usually 2 sections of violins, you can use harmony, resonance or even a blues-style "question-answer" type of approach. Also the violins are great for doubling the woodwind parts or playing it an octave higher - it adds a really dramatic effect to the melody, which is defied by the ongoing resonance of the both sections - the sounds will become thicker and more dense.
2.2 Melody in Violas
Violas are not that great for usual classical melodies, mostly because of the tone it produces. But if you are planning to play something more contemporary or even weird, you can always rely on the violas to produce a really distinguishable and unique sound. It is usually a good idea to make a "dialogue" between violas and violins or woodwinds. Viola is a really good thing to experiment with and it can do some amazing things with your compositions.
2.3 Melody in Cellos
Cellos are usually played witin the tenor-bass range and are always good for both passionate and dramatic melodies. The tone of the Cello is very rich, that's why it can be used as a solo instrument too. But usually in the orchestra some parts of the cello melody are better to be doubled by woodwinds or, even better, violins. The synergy between cellos and violins is great, so use this melodical potential wisely! And don't forget about stunning staccato possibilities, which will make you lines and runs surely more dramatic and powerful.
2.4 Melody in Double Basses (DBs)
DBs, due to their very low register, are not often used for melodies. However, in a jazzy or bluesy kind of piece it can shine in all its brilliance, playing the best of the solos and all kinds of interesting things. So don't be afraid to use DBs, but be careful, the muffled tone and the low pitch can ruin the composition, if it is not used wisely!
2.5 Melody in woodwind instruments
Writing and orchestrating for woodwind instruments is usually hard because of the tones. Woodwind instruments can't be explained like the strings, however, some common methods can be distinguished. Woodwinds have some great sustain and legato possibilities, so it's convenient to use them in both quick runs or slow passages. It is advisable to use woodwinds in the octave or unison groups (i.e. playing octaves or in unison with different instrument). But it is interesting to experiment with solo woodwinds too, especially in oriental or folk music, as the flute-like instruments are rooted in folk culture. Also you can distribute the melody in, for example, fifths, thirds and sixths between the woodwind instrument sections. However, this takes serious practice and it is advisable to try different combinations on your own.
2.6 Melody in brass instruments
Like the woodwinds, brass instruments are also very hard to explain melody-wise. But the most important things everyone should know is that the brass section is incredibly powerful in its sound. So you have to use it carefuly, as the brass can dominate every other instrument easily. The tone of usually a piercing sting-like sounds, so it will cut through even in the toughest and tightiest orchestration even. But you should always keep in mind that the power will come only with the correct usage. So consider investing the time in checking out different combinations of tone and staccato/legato possibilities. You can expect to fail a lot in the first stages of the learning, but don't be afraid, it's okay! :)
This was the basic information about the panning and melody. Next time we will talk about how to group the instrument together for the best melodic possibilities and tonal options!