The Hall of Voices was a chamber located in the city of ShiKahr on the planet Vulcan.
It was an open hall which was a huge enclosed amphitheater several meters underground. Here, in traditional Vulcan fashion, open debates were held on various topics. In these types of debates each side presented its case to members of the audience, who in turn asked questions as each speaker explains their position. (Last Unicorn RPG module: The Way of Kolinahr: The Vulcans)
In 2275, the Hall of the Voice was used by the Vulcans to debate the Referendum in regards to their people leaving the United Federation of Planets. (TOS novel: Spock's World)