The stereo image is produced by the off-axis attenuation of the cardioid microphones. While A-B stereo is a difference-in-time-stereo, the XY stereo is a difference-in-level stereo. But as the off-axis attenuation of a typical cardioid microphone is only around 6dB at 90 degrees, the channel separation is limited, and wide stereo images are not possible with this recording method. Therefore, XY stereo is often used where high mono-compatibility is needed - for example, in broadcasting situations where many listeners still receive the audio on mono equipment. Since the sound-sources are mainly picked up off-axis when using the XY stereo setup, high demands are placed on the off-axis response of the microphones used.