Yes you can, and there's two options.
1) We offer a 15 day money back guarantee. This means you can order your server, and have 15 days to try it, and if you don't like it, you can get a refund.
2) We offer small test servers in each location for each service we sell. Simply click on the location on the product page, and you'll be connected to a test server in that location.
Test Mumble Locations: https://www.supremevoice.net/products/mumble#testservers
Test TeamSpeak Locations: https://www.supremevoice.net/products/teamspeak#testservers
Test Ventrilo Locations: https://www.supremevoice.net/products/ventrilo#testservers