A high/low shelf filter is going to affect everything above or below where the frequency mark is where as a peak filter only affects the area around the frequency mark based on how wide the Q is. A common example is this: You have two options, a low shelf filter and peaking filter both at 300 hz cutting 2 dB. The shelf filter is going to affect everything below 300hz so you can expect to hear less bass and kick drum. The peak filter will only affect the area around 300hz so you can expect the kick and bass to not be affected. Let me know if this helped or if you'd like me to explain it more