By default, all available music services are shown in the left-hand drawer of the Controller user interface. To login to a service, click the user silhouette icon and then click the 'Login User' + button. There is no limit to the number of logged in users you can have for each service at one time. So for example, each family member may choose to log into their iHeartRadio account within audio|acacia simultaneously.
In the footer of each 'listening session' is listed the name of the music source from which the session is playing. If the music source is an online service with user accounts, the name of the user will be listed alongside the icon of the source. All play counts, ratings, and favorites that are made in this session will apply to this user.
The controller interface handles the concept of multiple users by always having a 'selected user'. The currently selected user is indicated by the user with the blue box around its profile picture. Clicking on a different user will select that user. Browsing, searching within the music service is always done in the context of the currently selected user. If you then select a song to be played to a listening session, it will play that song in the context of the currently selected user of that particular interface. Each instance of a controller interface may have a different selected user. In this way, a family can each be browsing their own user accounts simultaneously but independently without overwriting each other.
Some music services are region specific and may not show up for you depending on where you live. In addition, there are a few services that require a premium subcription in order to be used within audio|acacia. Most other services can be used free and without registering for an account, though some services have limited functionality without signing up for a free account. Lastly, some services limit the number of simultaneous streams that can occur. The details are listed below.