A modular cochlear implant system comprising: a stimulator configured to provide stimulation signals; an input source configured to receive an input representative of ambient sound and generate an input signal representative of the received input, wherein the input source comprises a middle ear sensor and/or implantable microphone; a signal processor in communication with the stimulator and the input source, the signal processor being programmed with a transfer function such that the signal processor outputs a stimulation signal to the stimulator based on the input signal received from the input source and the transfer function; and an implantable battery and/or communication module in communication with the signal processor and being configured to provide electrical power to the signal processor, the implantable battery and/or communication module including a wireless receiving device configured to receive a transmitted signal from a source external to the patient; wherein the stimulator, the input source, the signal processor, and the implantable battery and/or communication module are fully implantable into a patient; wherein the signal processor is in communication with the stimulator via a first detachable connector; the signal processor is in communication with the input source via a second detachable connector configured to detachably connect the signal processor and the input source and provide communication between the signal processor and the input source when attached; the implantable battery and/or communication module is in communication with the signal processor via a third detachable connector and configured to provide electrical power to the signal processor via the third detachable connector; and the signal processor is configured to: receive a first input signal from the middle ear sensor and/or implantable microphone; receive a second input signal from the wireless receiving device; and output a stimulation signal to the stimulator based on the received first input signal, the received second input signal, the transfer function, and a programmable mixing ratio representative of the relative contributions of the first input signal and the second input signal to the output stimulation signal. a stimulator configured to provide stimulation signals; an input source configured to receive an input representative of ambient sound and generate an input signal representative of the received input, wherein the input source comprises a middle ear sensor and/or implantable microphone; a signal processor in communication with the stimulator and the input source, the signal processor being programmed with a transfer function such that the signal processor outputs a stimulation signal to the stimulator based on the input signal received from the input source and the transfer function; and an implantable battery and/or communication module in communication with the signal processor and being configured to provide electrical power to the signal processor, the implantable battery and/or communication module including a wireless receiving device configured to receive a transmitted signal from a source external to the patient; wherein the stimulator, the input source, the signal processor, and the implantable battery and/or communication module are fully implantable into a patient; wherein the signal processor is in communication with the stimulator via a first detachable connector; the signal processor is in communication with the input source via a second detachable connector configured to detachably connect the signal processor and the input source and provide communication between the signal processor and the input source when attached; the implantable battery and/or communication module is in communication with the signal processor via a third detachable connector and configured to provide electrical power to the signal processor via the third detachable connector; and the signal processor is configured to: receive a first input signal from the middle ear sensor and/or implantable microphone; receive a second input signal from the wireless receiving device; and output a stimulation signal to the stimulator based on the received first input signal, the received second input signal, the transfer function, and a programmable mixing ratio representative of the relative contributions of the first input signal and the second input signal to the output stimulation signal. receive a first input signal from the middle ear sensor and/or implantable microphone; receive a second input signal from the wireless receiving device; and output a stimulation signal to the stimulator based on the received first input signal, the received second input signal, the transfer function, and a programmable mixing ratio representative of the relative contributions of the first input signal and the second input signal to the output stimulation signal.