So a fraction of a dB.Depends how big that fraction of an ohm is compared to the lowest impedance of the speaker.
Lets say a speaker impedance dips to 3 ohms at a particular frequency (not unusual). In this case a 0.3 ohm fraction of one ohm resistance will cause a 10% dip (-0.92dB) at that frequency.
That is going to change the voicing of the speaker?
I could slide to scratch my bum for a second and cause more change .
When it comes to transducers in an acoustic environment, a couple of dBs here and there is hardly noticeable.
I would take more care with termination, than the cable itself.