RWE Innogy planned to build 20 turbines between Farr and Tomatin, south of Inverness, but the site was deemed too close to the established 40-turbine Farr wind farm, which the company has been operating for eight years.
Noise, in particular, was a concern, with predictions that at two properties the levels would be close to the limits set within national noise guidance and standards. Councillors did not accept that an undertaking to turn off turbines if the noise levels were too high would provide sufficient protection.
Councillor Carolyn Caddick said: "I have had a lot of complaints in the past from residents, so I know noise is an issue in the Tomatin area.
"But my main concern is the cumulative visual impact of this. These turbines are 360ft high. They are higher than the 40 we already have at Farr. It would be a 50% increase bringing the whole scheme to 60 turbines."
Councillor Margaret Davidson, said: "Many people think Farr wind farm looks nice on the landscape, but putting more turbines next to an acceptable wind farm does not necessarily make for a bigger acceptable wind farm."
Keris McLeod, of RWE, said: "We are surprised councillors have gone against the planner's recommendation for approval. We have the right to appeal and are considering our options."