1. An apparatus comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to at least: cause reception of a plurality of signals during a conference session between a plurality of participants including a plurality of local participants at one location and one or more remote participants located at another, remote location, the signals being representative of voice communication of the participants, classify speech activity of the conference session based on the signals, the speech activity being classified into a plurality of distinct classes reflecting a presence or absence of one or more actively-speaking participants and the one or more actively-speaking participants being local or remote participants, said distinct classes comprising speech pause being no actively speaking participants, transmitter talk being one local actively speaking participant, simultaneous talk being multiple local actively speaking participants, receiver talk being one remote actively speaking participant, double talk being one local actively speaking participant and one remote actively speaking participant, and simultaneous/double talk being multiple local actively speaking participants and one or more remote actively speaking participants; and mix the signals of the respective local participants into at least one mixed signal for output to the one or more remote participants, the signals being mixed based upon classification of the speech activity.