In an SSB/CW receiver, which stage could include an audio band-pass filter?

An audio band-pass filter is designed to pass frequencies that fall within the human hearing range (typically tailored to voice frequencies, around 300 to 3000 Hz) while blocking higher or lower frequencies. Because it operates on audio frequencies, it naturally belongs in the audio frequency (AF) amplifier stage of the receiver. Placing the filter in the AF amplifier helps to eliminate high-pitched hiss, low-frequency hum, and adjacent channel chatter that made it past the earlier stages of the receiver, significantly improving listener comfort and intelligibility. The distractors mentioning IF (Intermediate Frequency) stages are incorrect because those stages process radio frequencies, not audio frequencies. While an IF filter shapes the radio signal's bandwidth before demodulation, an audio band-pass filter shapes the sound after it has been demodulated.