Even though bidirectional, high-quality and low-latency audio systems for network performance are available, the complexity involved in setting up remote sessions needs better tools and methods to asses and tune network parameters. We present an implementation of a system to intuitively evaluate the Quality of Service (QoS) on best effort networks. In our implementation, musicians are able to connect to a multi-client server and tune the parameters of a connection using direct "auditory displays." The server can scale up to hundreds of users by taking advantage of modern multi-core machines and multi-threaded programing techniques. It also serves as a central "mixing hub" when network performance involves several participants.