A hydraulic mount assembly includes a pair of mounting members connected to each other through a hollow elastomeric body. The body is closed by a resilient diaphragm so as to form a cavity for damping liquid. A partition is provided to divide the fluid filled cavity into two distinct chambers. A primary chamber is formed between the partition and the interior wall of the body. A secondary chamber is formed between the partition and the interior wall of the diaphragm. The partition includes at least one orifice track connecting the two chambers. There is further provided a domed orifice plate in said primary chamber. The orifice within the orifice plate allows restricted fluid communication between the primary chamber and the flow passage in the partition. During operation, this orifice provides a passive tuning mechanism for the mount by lowering the dynamic rate at higher operating frequencies. This provides for a desirable softer, quieter mount at the higher frequencies and an improved balance of engine control/engine isolation in the mount.