Biwire Speaker Question

Of course four wires of the same quality will cost you a lot more than two (double). Hard to compare say a pair of $400 biwire cables against two pairs of $200 single wires. They are not going to be the same wire.

Well here's what I just learned. Two sets of cable to bi-wire has the advantage of being able to compare bi-wired to single wired. In my case single wired with matching jumpers actually sounds much better on my speakers. My last speakers were far better bi-wired, so I think it's important to hear high quality cables on your speakers both ways to make an informed decision, which you can't with the bundled run of bi-wire. As always, YMMV.

Didn't see a mention of this, but I have heard the reason for bi-wiring is not to increase the guage of wiring but to keep innercable frequency interference to a minimum. When a signal from your amp goes to the speaker it makes the speaker move. When a voice coil moves in a magnetic field it generates a back current that goes to the amp. Appearantly high and low frequencies behave differently in a conductor and dividing the wiring to the high and low drivers is of benefit (even though they meet at the amp terminals). It's not mentioned in your thread if your speakers have separate terminals for mids and highs. True bi-wiring is about running two sets of wires from the high and low terminals on your speaker back to the single amp terminal on your amp (not all companies design their speakers for this).
Depending on the make of wire, some manufactures recommend a double run for improved perfomance. OCOS speaker cable ( a coax design imported by Sumiko Corp.) is such an example. In this case, lower mid and bass are improved by a double run. This application essentially increases the amount of signal going to your speaker. While not a true bi-wire set up, this configuration does improve the sound. Fortunately OCOS is relatively affordable and I was able to do this. Cost can be significant if you're talking Nordost and the like. Sometimes the money is better spent using better cable instead of twice as much. Ya just gotta listen to it!
So bi-wiring is about the physics of two way traffic in a speaker wire between the amp and the speaker.

I’m also contemplating bi-wiring my speakers. Some cable makers claim that they sell “true bi-wire,” which I take to mean the equivalent of the four separate wires described by Kurt tank but wrapped in one or two separate sheaths per speaker. If I decide to go with such a cable, I’m certainly going to question the manufacturer first to be sure that the wire connected to each speaker terminal is not half (the gauge) of the wire connected at the amp terminal.

My question is, from an electrical interference point of view, is it better for the wires to be packaged in two sheaths or even a single sheath per speaker, which looks neater and may reduce the chance of tripping over wire, or should the four wires to each speaker be kept apart?

You have to compare apples to apples here.

Whether your biwire cabling is two separate sheaths or one sheath with two cables inside, the wire gauge at the amp end is going to be the sum of the wire gauges at the speaker end.

The OP asked if the connection at the amp end was better made to a single output post (per channel), or divided between the two output posts available. Kal's monosyllable was correct IMHO, electrically and sonically.

The best reason to use both posts is convenience and secure connection. If you have two sparate cable runs, they connect to the speakers on two different posts, and the nuts on those posts are easy to screw down tight. When you connect those two wires to a single post on the amp, they may not be easy to tighten and keep tight, especially if the wires are heavy and the connectors are large spades.

If, like me, you have a single, two-in-one biwire cable (a "shotgun" configuration), the two wires are joined together at the amp-end connector. Connecting this to a single binding post is easy.