Would you change your amp selection knowing...?

Adding a network to an amplifier to correct for a cable is a tailspin, just adding eq to eq.

I’d like to see how Goertz calculates a Z of 4 or 8Ω at audio frequencies from their geometry.

SS amplifier outputs are a tiny fraction of 8Ω which is what gives rise to large damping factors. Characteristic impedances are beneficial when the source and load impedances are matched. Almost no speaker is a flat 4 or 8Ω impedance, largely negating any supposed benefit. Typical impedance variations of 4:1 are common and 10:1 is not uncommon.

See Cable Snake Oil Antidote Amplifier Output to see how amplifier output impedance can interact with cables.

I’d like to see how Goertz calculates a Z of 4 or 8Ω at audio frequencies from their geometry.

Hi Ian,

The table near the bottom of the following page of their website indicates R, L, C, and Z for their various speaker cables:

http://www.bridgeportmagnetics.com/contents/en-us/d62_MI_AG_Speaker_Cables.html

As I’m sure you are aware, characteristic impedance can be calculated to a close approximation as the square root of (L/C), using those parameters on a per unit length basis and provided that conductor resistance per unit length and dielectric conductance per unit length are insignificant. The L and C values shown in the table appear to be consistent with the indicated characteristic impedances, which range from "~1.7" to "~4" ohms.

Best regards,
--Al

I have several sets of cables at home, my favorite are high count twisted litz. These cables definitely qualify as high capacitance. This capacitance problem is also effected by the speaker crossover itself that is attached to the cable.  
So depending on crossover design and layout combined with cable, a problem with speaker cables capacitance can occur with amplifiers that have a lot of feedback and some high-feedback push-pull tube amps. A capacitive load can drive the feedback phase far enough to lead to oscillation, sometimes at ultrasonic frequencies. You might not hear it, but soon there's smoke coming out of your tweeter.  

@almarg
I’ve never used (L/C)^0.5.

I conceptualize cables as a (SERIES LR with PARALLEL C) x Length. First sum the LR impedances and then add the inverse of the LR sum to the inverse of the C impedance. Z=1/(1/(ZL+ZR)+1/ZC) * Length. It's actually more complicated because ½L is in each lead and R is in both leads with the cap between them

Using the numbers on the link for Divinity, 4nH .98mΩ 1.5nF / ft, I come up with ~0.05Ω @ 1KHz. The impedance is impressively flat relative to a 2 wire standard, but nowhere near 4Ω.

This impedance is in parallel with the amp and speaker. Since the value is so low relative to the speaker impedance, the impedance remains low well past the audio band and can cause some amplifiers problems, particularly if the speaker has a very low Z minima.

A ’benefit’ of plain old speaker cable is its impedance is rising, thus preventing amp problems. The downside is the rising impedance, quadrupling in the region where the ear is most sensitive, is reacting negatively in terms of phase.