I'm not sure if you NEED a managed switch, all my switches in my network are managed. I'm attaching a diagram if it helps. This is my configuration.
Let's say I have VLAN 5 on the MX and VLAN 10 on the voip router
Both of these are connected to a Netgear switch. I'm using VLAN 5 (U) and VLAN 10 (T)
The I simply connect the phone to the switch, and my phone is configured for VLAN 10. Connect the cable from the switch to the phone port labeled LAN to get VLAN 10 (from the voip router), then connect the cable from the phone labeled PC to PC to get the VLAN from MX (in my case VLAN 5)
What kind of voip router do you have, and what kind of voip phones?