Take a look at fairly standard cable used for telephones. It has a characteristic impedance that varies quite a lot in the audio range: -
And, this effect is as a direct result of the standard characteristic impedance equation for a transmission line. As frequency drops into the audio range, R starts to dominate over jwl and the impedance becomes: -
As frequency lowers more the impedance tends to become: -
And, at much higher frequencies, the characteristic impedance is the standard formula used by RF guys: -
It's also noteworthy that many sources refer to a transmission line as "distortionless" if the ratio R to G is the same as L to C. When this happens, the impedance is constant from DC to any frequency.