Differential audio data compensation

A speakerphone comprising:

• a speakerphone housing,
• wherein a first microphone and a second microphone are arranged in the speakerphone housing,
• an output transducer arranged in the speakerphone housing,
• a processor in communication with the first microphone, the second microphone and the output transducer, wherein the processor is configured to receive electrical signals from the first microphone and the second microphone, wherein the electrical signals represent ambient sound received by the first microphone and second microphone respectively,
• a first calibration unit, wherein the signal from the first microphone is fed to the first calibration unit which is configured to provide a first calibrated signal,
• an adaptive filter configured to receive the first calibrated signal, the adaptive filter providing a first filtered output signal based on the received first calibrated signal,
• a second calibration unit, wherein the signal from the second microphone is fed to the second calibration unit which is configured to provide a second calibrated signal,
• wherein the processor is configured to establish a processed signal based on the first filtered output signal and the second calibrated signal, wherein signal contributions from the output transducer are substantially eliminated in the processed signal.