In a receiver, which stage is controlled by the volume control?

The volume control in a receiver adjusts the amplitude of the audio signal so you can set a comfortable listening level. This adjustment takes place in the Audio Frequency (AF) amplifier stage, which directly drives the speaker or headphones. Other stages, like the Intermediate Frequency (IF) amplifier, process the radio signal before it is converted into sound. Adjusting the IF stage would change receiver sensitivity (gain) rather than simple audio volume. The limiter and discriminator are specific to FM radio signal demodulation, not the final audio volume adjustment.