Oscar, another possible solution is replacing the batteries. Unlike some headphones, Beats Studios will not work without batteries. You can access the battery housing by twisting the circular piece of plastic with the Beats logo that is on the side of the headphones with the audio cable jack. The plastic cover should turn a little and then fall off easily. This guide walks you through what I just explained: Beats Studio First Generation Batteries Replacement.

Hope that helps!

If the replacing the batteries does not fix the problem, I would recommend looking through this troubleshooting page: Troubleshooting Beats Studio First Generation