The audio quality of talkback systems is usually markedly lower than that of studio microphones and speakers, coming from a simple microphone (which may be omnidirectional or unidirectional) built or plugged into the audio mixer, and with its sound often compressed. Since talkback is usually edited out of master recordings, high fidelity isn't essential, and studios tend to cut budget corners when possible. Compression allows comments from around the control room to be audible.
