Mid Sweden University

This study investigates the possible use of GNSS synchronized PTP grandmasters as a general method for synchronizing IP audio equipment. Two relatively low cost GNSS synchronized PTP grandmaster clocks were built and tested in various real world scenarios. Low latency audio streams were sent over internet between GNSS synchronized audio devices via the protocol SRT, Secure Reliable Transport, and the result was compared to using the commercially available service Jamkazam. It was found that the solution with distributed GNSS synchronized IP audio devices worked well over both LAN and WAN, but the specific SRT solution tested was not suited for really low latency usage like NMP, Networked Music Performance. Further studies are needed to find alternate SRT solutions or other protocols for use when very low latency performance is needed. It was also found that the lowest latency possible was not the most desirable latency when used for monitoring mixes in an NMP context. A latency of 15-20 ms was generally the most preferred, indicating monitor mixes for IEM, In Ear Monitoring, might benefit from introducing delays in the signal chain. More studies are needed to investigate this further.