A heterophonic texture is the simultaneous variation of a single melody line. A variation of the melody is played over the original melody. Heterophony is often found in gamelan music.
Heterophonic textures can be heard in Baroque cantatas or oratorios, where an instrumentalist or vocalist plays a slightly more decorated version of a melody line over the original. Here is an example of what heterophonic texture looks like in Western classical music:
An antiphonal texture is when there is more than one group of instruments or voices, usually placed in different parts of a church or concert venue. There is usually dialogue between the two groups and melodic ideas will be passed between them.
The renaissance composer Giovanni Gabrieli used a lot of antiphony in his writing. Much of his music was written to be performed at St Mark’s church in Venice. He was able to position choirs and groups of instruments around the church and make the most of the different positions of these voices and instruments. An example of this is his famous motet In Ecclesiis.
Michael Tippett’s Concerto for Double String Orchestra is also an excellent example of homophony - the two orchestras have a musical dialogue, playing together and individually.