There is at least three bands called One Voice:

1) One Voice is a hardcore / punk band from Belgium.

2) One Voice was a legendary hardcore / punk band from Rīga, Latvia in 90-ties. They played their last show at club "Saxophone" on December year 2000 with bands Schizma and Bramborak.

The original lineup:

Viesturs Irbe - vocals;
Renārs - guitar;
Kārlis - bass guitar;
Kārlis Purviņš - drums.

www.tornis.lv/to/parejie/viesturs.htm

3) One Voice was a Eurodance group from Poland, under the labels Star Maker and Dance World, active from (appx.) 1997-1998. They released one album in 1997 called "The Best" and had a number of hit singles in Poland, such as "Family Man", "Moonlight Shadows", and "El Condor Pasa".