Comparison of the BPASS (panels A and B) and SEBA (panels C and D) model populations to the observed systems from the Munday dataset (panels A and C) and the ZTF dataset (panels B and D), in terms of the GW frequency and distance of the binaries. Each rectangular cell represents a frequency-distance bin and is shaded according to the number of systems the population synthesis model predicts for that bin; white indicates that zero systems are predicted. Each red dot is an observed system.