Tech Tip:How to Make Orchestral Samples Sound More Realistic?
Samples won't ever sound exactly like real orchestral instruments. But they can sound fairly close. Here are a few helpful principles to remember.
Be sure to play the samples within the range of the actual acoustic instrument. Use phrasing and dynamics appropriate to each instrument. MIDI volume can add expression to phrasing. Don't sustain wind instrument samples beyond a wind player's breath capacity. Ranges and idiomatic instrumental usage can be found in orchestration books. Avoid playing anything on a sampled instrument that can't be played on the real instrument.
Vibrato can be problematic. When a sample with natural vibrato is played more than a half-step above or below the note at which it was sampled the vibrato speed will be inconsistent, especially with wind instruments. In such instances, use samples without vibrato, which can be added via LFO or pitch-bend wheel.
In an orchestra, instruments occupy a given place on a stage or in a room. Use mono samples, and pan instrument sections to a consistent location. Reverb can help simulate front-to-back placement, as wee as add hall ambience. Examples of orchestral seatings can be found in some orchestration books.
Samples can be recorded with various mic placements and effects processing. Maintain consistency as much as possible; effects processing can help.
Orchestration books are invaluable. Books on MIDI orchestration are even more to the point.