below 100hz, do speaker cables matter?

Yes, more than for other frequencies in most cases.

My argument lies with voltage divider effect, eloquently explained by Al (Almarg) in this thread http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1336159920&openflup&3&4#3

Given that most speakers exhibit their lowest impedance in a range below 100 hz, it would follow that the impact of cables inductance would be the greatest on the bass notes.

Also the omnidirectionalality of bass frequencies has to do with the propagation through air and not of the signal in cables. So the fact that bass is omnidirectional and mids and highs are not, IMO should have no bearing on cable design.

Al, it seems I am still a little confused on the issue.

If inductance has a neglible effect at low frequencies due to its proportionality to frequency. Then the slight correction, is no longer slight.

The op sates "outside of cable gauge", or in other words, other than insuring low resistance, all other factors should not have an impact on low frequencies.

What I understand from your post is that you agree with this statement. That is within the realm of measurable and predictable outcomes.

Al agreed!

Douglas, at negative hertz values you can use imaginary cables "i cables"