Sunsoft had so frequently used the DPCM channel for a string or electric bass that we have come to colloquially refer to it here as "sunsoft bass".
The DPCM channel reconstruction is effectively an infinite lowpass filter. ("infinite" in the sense that the corner frequency is 0; for every pair of frequencies f and 2f, f can be represented twice as loud as 2f).
(Obviously at some point the channel saturates. At highest, that's frequencies below 258 Hz. Anyway, I'm ignoring that for now)
This encoding does an adequate job as long as its input is sufficiently bandlimited (say maybe 1kHz from lowest frequency you want to store to highest). The more bandwidth, the worse DPCM is at encoding it.
As an example, here's the first 7 seconds from
David Byrne's My Fair Lady on The Wired CD (CC:Sampling+ license). First 7 seconds are post-filtering, second 7 seconds are additionally after encoding and decoding. I've applied a very strong bandpass to retain just the frequency band from 500Hz to 1500Hz.