The spectrum compensation technique in voice processing systems can be used for both attacks and defenses. For attacks, it allows attackers to manipulate audio signals by compensating for frequency distortions caused by playback devices, making replay attacks like modulated replay attacks more effective. This is achieved by designing inverse filters that counteract the speaker's frequency response, making the replayed audio appear more like genuine human speech.
On the defense side, the same technique can be used to detect and mitigate attacks. By analyzing the frequency spectrum, defenses can identify anomalies caused by spectrum compensation, such as the presence of ringing artifacts in the time domain. This dual-domain approach (frequency and time) enhances the ability to detect and defend against various voice attacks, including replay attacks and spectrum reduction attacks.