The dc blocker is an indispensable tool in digital waveguide modeling
and other applications.^{11.4} It is often needed to remove
the dc component of the signal circulating in a delay-line loop. It
is also often an important tool in multi-track recording, where dc
components in the various tracks can add up and overflow the mix.

where is a parameter which is typically somewhere between and
(for a 44.1 kHz sampling rate, is good).
The transfer function is

(11.10)

thus, there is a zero at dc () and a pole near dc at . Far
away from dc, the pole and zero approximately cancel each other.
(Recall the graphical method for determining frequency response
magnitude described in Chapter 8.)