There are several group chat clients available like TinyChat e.t.c., but very few that allow you to do a group voice chat for free. Voxli is one such app.
Voxli is probably the easiest way to do a voice conferencing online. It doesn’t require any installations any setups or any registrations on part of the participants. If you are the person initiating the chat, simply send the URL to everybody you want to invite. As soon as they go to the URL they’ll be instantly connected to the voice chat. If you don’t want just anybody to enter your chat, you can password protect it and require every participant to enter the provided password. You can also setup a startup message that every participant would see as soon as they join. This might be chatting instructions, an important link or just a simple introduction.
Voxli can accomodate upto 200 people in a single group chat. Just press the Push to talk button whenever you wish to speak. Voxli is totally free and allows you to create as many voice chat sessions as you want. It is compatible with both Windows and Mac.
Voxli can also be used outside your browser and inside your games. It is compatible with almost all gaming handsets and allows gamers to interact with others without any hassle.