Chamber orchestras vary in size, just as people do. A chamber orchestra may comprise as few as 13 (the smallest number that can sound like an orchestra) or as many as 20 string players, plus winds. A symphony orchestra usually musters a string body ranging upward from, say, 35 string players.
In between lies the clean, pliable ensemble of a classical orchestra. Two to three dozen strings nicely balance the dozen wind instruments called for in orchestrations of that period. Balancing instrumental sonority with orchestral economics to fill this neat niche, a number of fine classical orchestras have established themselves as important contributors to the world's musical scene.
Prague Philharmonia Orchestra