from an article on SoundonSound.com
When programming any orchestral string parts, as when programming brass parts, you should always try to think of the orchestra as a collection of individual instrumentalists, as opposed to simply a collection of different instrument sections.
We've all got our favourite string preset or multisample, and when we play a big G minor chord they sound great, but this is quite different from the workings of a real string orchestra. Violins, cellos and violas normally only play monophonically, and the arranger's job is to allocate each note of a chord to a particular section -- for example, cellos could play the root (A), violas could play the third (C#), and the violins might play the fifth (E). The resulting sound is a complete chord of A major, and the richness and depth of any arrangement is in the way in which these elements interact and combine throughout a piece. Again, as with the brass parts, it can take a bit more time to program string parts in this way, and it also requires a greater knowledge of the chord structures you're using, but the end result is nearly always richer, more interesting and undoubtedly more realistic than if you had simply 'strummed' the chords polyphonically using your keyboard.
If, however, you feel your playing really isn't up to the job, or you don't have the time, you can always cheat a little by taking a chord track and using the command within your sequencer software that extracts the top and bottom lines of any given chord track. You can then assign these individual monophonic lines to different tracks, and therefore different sounds. For example, drop the lowest note of the chord by an octave (12 semitones) and assign it to a cello sound, then perhaps take the top line, make a copy of it, raised by one octave, and assign both tracks to the same violin sound. This certainly 'widens' the sound of a chord and is much more in keeping with a real string ensemble.
When you're programming these individual single string lines, you may find that there are slight gaps between the notes you've played (caused by releasing the keys a bit early, in order to move to the next note). This can be cured by using your sequencer's 'Force Legato' command. This 'stretches' the programmed notes within a given section and triggers MIDI note off information only fractionally before the start of the next note. The effect is to 'glue' the notes together without any gaps, and can often be very effective.
If the string part is still feeling a touch hesitant, you can always try going into your edit pages and creating a slight overlap between the individual notes, so that each one plays slightly into the next (see Figure 2).
Another thing you might like to try, particularly if you're limited by polyphony or 'timbrality', is using a string preset with a fairly fast attack time. This helps to ensure timing accuracy. With most samplers and sound modules, it's a relatively simple procedure to programme the attack time to be proportional to key velocity. This gives you a good amount of flexibility for playing both soft 'legato' phrases (at a lower velocity) and sharper or 'spiccato' lines when playing the keyboard a bit harder.
