Smooth filter in simulink and transfer function

HI, I'm working in the alignment of audio systems, and I'm trying to make an measure tool in real time, So I'm using simulink, I get the signal of pink noise and measure signal of the microphone channels, use a blackman window to limit the FFT to get the frecuency response, and use welch's average of the each signal. First at all I want to use a smooth filter but I dont know how configure it in a digital filter and second of all, after the smoothing process, I want to get the transfer function, I know maybe it's just a simple division but I want to know what block I can use. Thanks