  This paper describes an architecture design process for Networked Music
Performance (NMP) platform for medium-sized conducted music ensembles, based on
remote rehearsals of Academic Choir of Gdansk University of Technology. The
issues of real-time remote communication, in-person music performance, and NMP
are described. Three iterative steps defining and extending the architecture of
the NMP platform with additional features to enhance its utility in remote
rehearsals are presented. The first iteration uses a regular video conferencing
platform, the second iteration uses dedicated NMP devices and tools, and the
third iteration adds video transmission and utilizes professional low-latency
audio and video workstations. For each iteration, the platform architecture is
defined and deployed with simultaneous usability tests. Its strengths and
weaknesses are identified through qualitative and quantitative measurements -
statistical analysis shows a significant improvement in rehearsal quality after
each iteration. The final optimal architecture is described and concluded with
guidelines for creating NMP systems for said music ensembles.
