Excessive DC and low frequency content in audio playback signal can damage loudspeakers. The playback path employs a high-pass filter (HPF) to prevent this from occurring. The HPF is a 1st order filter and can be changed from the default 2 Hz for 48ksps fs using the AUDIO_HPF_N0, AUDIO_HPF_N1, AUDIO_HPF_D1 registers. The HPF filter frequency scales with change in the FSYNC clock and can be re-configured to achieve the required cutoff frequency for different FSYNC clock frequencies. The coefficients can also be changed to disable the HPF coefficients appropriately. These coefficients should be calculated and set using PPC3 Software Section 6.4.1.