As the saying goes: EQ doesn't cause phase shift, phase shift causes EQ. The conceptually simplest to understand filter for beginners however would be the movi

As the saying goes: EQ doesn't cause phase shift, phase shift causes EQ. The conceptually simplest to understand filter for beginners however would be the moving average filter. Just keep a list of the last n samples, and average them. When a new sample comes in, throw out the oldest. In the end many low pass filters are some variant of this (adding one or more samples from the past to the current sample using certain weights, maybe with feedback thrown into the mix).