An apparatus configured to be used in treating tinnitus, comprising a sound processing unit, a tactile unit, and an interface therebetween, wherein: said tactile unit comprises an array of electrocutaneous stimulators each of which can be independently actuated to apply a tactile stimulus to a subject, and an input for receiving a plurality of actuation signals from said interface and directing individual actuation signals to individual stimulators; and said sound processing unit comprises: an input configured to receive an audio signal; a digital signal processor operable to analyse said audio signal and generate said plurality of actuation signals representative of said audio signal by dividing said audio signal into a series of frames in the time domain, performing a transform on each frame to generate a set of coefficients representing said frame, and mapping said set of coefficients to a set of actuation signals to be applied to the array; and an output configured to receive said plurality of actuation signals from said digital signal processor and to provide said plurality of actuation signals to said interface, the apparatus further configured to output the audio signal, said audio signal being output simultaneous with the actuation signals being applied to the array. said tactile unit comprises an array of electrocutaneous stimulators each of which can be independently actuated to apply a tactile stimulus to a subject, and an input for receiving a plurality of actuation signals from said interface and directing individual actuation signals to individual stimulators; and said sound processing unit comprises: an input configured to receive an audio signal; a digital signal processor operable to analyse said audio signal and generate said plurality of actuation signals representative of said audio signal by dividing said audio signal into a series of frames in the time domain, performing a transform on each frame to generate a set of coefficients representing said frame, and mapping said set of coefficients to a set of actuation signals to be applied to the array; and an output configured to receive said plurality of actuation signals from said digital signal processor and to provide said plurality of actuation signals to said interface, the apparatus further configured to output the audio signal, said audio signal being output simultaneous with the actuation signals being applied to the array. an input configured to receive an audio signal; a digital signal processor operable to analyse said audio signal and generate said plurality of actuation signals representative of said audio signal by dividing said audio signal into a series of frames in the time domain, performing a transform on each frame to generate a set of coefficients representing said frame, and mapping said set of coefficients to a set of actuation signals to be applied to the array; and an output configured to receive said plurality of actuation signals from said digital signal processor and to provide said plurality of actuation signals to said interface, the apparatus further configured to output the audio signal, said audio signal being output simultaneous with the actuation signals being applied to the array.