Something doesn't seem right about this...

If these wires are next to each other, the incoming signal (+) will be affected by the outgoing (-) won't it?

Yes, it will. The result of that will be a reduction in inductance, which is generally a good thing.

As described in this Wikipedia writeup, "a changing electric current through a circuit that contains inductance induces a proportional voltage, which opposes the change in current (self-inductance). The varying field in this circuit may also induce an e.m.f. in neighbouring circuits (mutual inductance)."

So the voltage induced by the current flowing in one conductor, which would tend to oppose rapid changes in current flow (i.e., which would tend to attenuate high frequencies), will be partially cancelled by the equal and opposite voltage induced by the current flowing in the other direction in the other conductor. Which amounts to a reduction in inductance, and therefore a reduction in the degree to which rapid changes in current flow will be opposed, compared to the situation where the two conductors are separated.

Regards,
-- Al

Hi ZD,

I agree completely with all of the comments Kijanki provided, as I usually do. (My response was narrowly focused on interaction between the signal currents flowing in the two conductors, which appeared to be what the OP was asking about). And, yes, we are saying that it CAN be a good thing for the two conductors to be twisted together.

I have no particular familiarity with the Tara speaker cables, but presumably if some of their models keep the + and - conductors separate their designs are either giving priority to factors other than those that have been mentioned, or are controlling those factors in ways other than by twisting.

Best regards, and happy holidays!

-- Al

A correction to your post, Willie, if I may. The specs for Kimber 12TC, and as I recall for many of their other cables, are for a length of 2.5 meters. See this page. ("DUT" presumably stands for "Device Under Test"). So the 1400 pf number represents only 171 pf/ft.

Very few speaker cables approach or exceed 1000 pf/ft. Some of the Goertz models are among the few that do, as are the old Polk Cobra cables.

I would add that speaker cables having capacitance that is high enough to approach, but not to reach, levels that might cause a given amplifier to oscillate, can nevertheless cause effects such as frequency response peaking, overshoots, ringing, and phase shifts that may have audible consequences. Particularly in the case of amps that use a lot of feedback. Those kinds of effects could perhaps be subjectively appealing in some cases, especially if not too severe, but are inaccurate in any event.

Regards,
-- Al

Hi Bruce,

Those are all reasonable numbers, and unlikely to account for any sonic differences that may exist among those cables, or between any of them and the majority of other cables.

The most notable spec difference between the three cables is their rated bandwidth, those numbers being 50, 150, and 300 kHz respectively (for response within +/- 0.5 db). Whether each of those numbers would result in sonics that are better, worse, or the same as the others is a function of many system dependent variables, and conceivably also on the RFI environment, meaning that the answer is unpredictable IMO.

Best,
-- Al