How does Baroque era music compare with music from the Medieval or Renaissance period? Does it have more or less depth and complexity?
More than the later Baroque music, Renaissance era music was more limited in terms of orchestration. While musical instruments were being invented and refined, there were, quite simply, fewer instruments from which to choose, and the compositions were not necessarily written with any particular instrument in mind. Consequently, Renaissance era music was routinely performed on whatever instruments were available. Also, it cannot be ignored that, during the Renaissance period, written pieces were rare given the absence of a mechanism on which to copy compositions -- the printing press was not yet widely -- and there is little documentation on musical compositions from that era.
Because of the lack of written documentation on which one could "read" music, compositions were passed along through demonstrations, which seriously limited the geographic expanse beyond which music could be shared.
Both Renaissance and Baroque era music were what is known as "polyphony," meaning they used used layered or harmonized melodies, a signature of the more sophisticated style of musical composition that resulted in no small part from the explosion of scientific and cultural creativity that gave the Renaissance period its historical significance.
When vocals are a part of the composition, which was not unusual, the distinctions between the two eras is more pronounced. Whereas Renaissance era music placed little emphasis on tonality, Baroque era music used much more forceful and demonstrative vocals. In addition, the lyrics in Baroque era music were much more precise in meaning than those in Renaissance era music, where lyrics seemed to serve little purpose with regard to any underlying meaning or message.
As mentioned earlier, the Renaissance period had fewer instruments from which to choose when composing or performing, often relying on the omniscient lute. As time evolved, and newer instruments were designed and introduced into orchestrations, Baroque music became characterized by the increased use of organs, harps, harpischords, and early variations of violins and bass. Many of these instruments were sparsely available if at all during the earlier period.
Baroque music reflected the increased possibilities of orchestral arrangements and compositions. Whereas Renaissance era music tended to remain on a single tempo for the duration of the piece, later Baroque era music introduced much more creativity into the compositions, with tempo changes being a common feature. Baroque era composers, for example, Bach, Vivaldi, and Handel, were more expressive in their music than their predecessors.
Baroque era music does not necessarily have more depth than the earlier Renaissance period music, but orchestrations were more complex given the expansion in the types of instruments available. To the extent that it is more complex is a product of the times in which each era occurred. The Renaissance period ushered in greater creativity, but was technologically more limited. Given that relative lack of technological sophistication, that the music was as complex as it was speaks to the intelligence of the composers of the time.