Cobalt cable theory on bi-wiring. Fact or fiction?


The follow was taken from colbalt cables web site. I was just wondering what those with more knowledge and experience think of this theory? If the theory is sound, it will save alot of people some money for more component upgrades. "Bi-wiring is a technique becoming quite popular in speaker applications. However, in our opinion, there are only a few situations where bi-wiring makes sense and MANY situations where bi-wiring is just hype. Here is what we think the complete story is about bi-wiring, and why it really does not make any sense for most people's equipment. The simple explanation for why the advantages of bi-wiring are very slight or nonexistent is that most people only have speakers built for bi-wiring, while their amplification is not. By using the same amplifier channel for both sets of bi-wire cables (both sets are connected to the same binding posts on the amplifier or receiver), the same electrical path is being used for both sets of terminals on each speaker, thus negating the core advantages of bi-wiring.

For example, most bi-wireable (we invented a new word) speakers come with some sort of plate or bar that connects the two (+) and the two (-) terminals (one for high frequency and one for low frequency) to each other. By using these plates or bars, you are "bridging" the two sets of terminals together creating only one connection point, so that you only need to make one speaker connection to each speaker.

By using the same amplifier channel (and terminals) for each set of bi-wire terminals on your speakers, you would be bridging the two sets of terminals together with your amplifier (since they share the same connection point on the amplifier). From an electrical perspective, this is NO different than running one speaker cable to the speaker, and bridging the two sets of terminals together with the bar or plate.

But wait, there's more! If you act now... (just kidding).

The only advantage in most setups (only speakers built for bi-wiring) for bi-wiring would be using twice as much physical wire (two separate runs to each speaker, thus dropping three gauge) as a standard wiring configuration.
However, if you are already using a fairly low gauge speaker cable (like our 10 AWG Ultimate Speaker Cable), there is little to be gained by "doubling-up". Plus, the added expense of running twice as much speaker cable for a barely audible (at best) difference, probably does not make too much sense.

The funny thing is, bi-wiring is actually a sound theory (pun intended, HA!), but the advantages can really only be had when it is used in conjunction with bi-amping (running more than one amplifier channel per speaker). In order to bi-amp the "right way", an external crossover between the preamplifier and each amplifier channel will be needed (so that only the high-frequency or the low-frequency parts of the signal will be amplified), and the internal crossovers inside the speakers will need to be disconnected (so that each amplifier will go directly to the corresponding speaker driver, i.e. the woofer for low frequency and the tweeter for high-frequency). WHEW! We personally don't know of too many people who will go to these extremes to take advantage of the benefits of bi-wiring, so bi-wiring just ends up getting WAY more attention than it should. We think that you should know what some of these other companies are up to out there. Straight-up and at ya partner."




dbx
They offer their theory, but like every other theory put out there, they offer no real proof to back it up.

To take their theory a few steps further; they state that since there is only one amplifier powering the speakers, it does not matter. Well the electrical power running the whole system is all coming from the same electric utility power plant. So I guess nothing we do matters. It is all the same power source. Ha ! LOL !!

Of course, my take on their theory is absolutely ridiculous. So is their theory likewise ??? Food for thought.
I agree with their reasoning. To me biwiring only makes financial sense if I am biamping, and biamping gets most gains when an active crossover is used.

But this is not to say that biwiring with a single amp, or biamping without an active crossover don't make a difference ... just they aren't the optimal use of resources.
Well, they may be right if the jumpers are in place at the speaker end, but of course, why leave them in place if you are bi-wiring?
SeanTaylor99, I think you are right,I know someone,
who has a set up, like the one you are describing.
Yes it sounds good the layering, the depth, the air,
vocal is world class.I read about this active thing,
I am not sure, if its on DECWARE web.Active with
crossover works, but too much work.This guy own the Norh
amp, they use to have those amp,with built in crossover
for active set up,I think,They are no longer making them.
Please correct me if I am wrong.
For a speaker that is "bi-wireable" you can hear the difference between ...
(a) A single wire from the amp with a jumper at the speaker terminal
(b) An Internal bi-wired cable, and
(c) Two seperate cable runs from the same output terminals on the amplifier.

Try it.

Good Listening!
Swampwalker: The wording of the website excerpt was a bit ambiguous, but they don't mean to suggest a scenario where someone would attempt biwiring with the jumpers still in place (not that, to them, it would make any difference if you did, unless perhaps your jumpers really sucked). They're saying that in their opinion there is no real difference (from an electrical connection standpoint) between the point at which the treble and bass speaker terminals are tied together being at the speaker end (jumper w/single wire) or at the amp end (single binding post [per leg] w/biwire) - *except* possibly for the fact that biwiring with everything else being equal implies up to a 100% increase in the effective conductor mass. If you buy that position (and I do), then biwiring is mostly a marketing chimera, with doubled speaker terminals only being (maybe) productively employed for biamping.
I just had to put my 2c in. To understand the benefit of the biwiring you have to realize that speaker wires are not ideal conductors and low and high frequencies have different effects on the wire.
Low frequency signal carries most of the current, and high current means high magnetic fields around the wire.
High frequencies are more affected by the capacitance of the dielectric material.
So, by making low and high frequency signals travel separately from amp to the speaker terminals they have less interference on each other and each part of the speaker cable can be designed for the optimal performance in their frequency range.
I hope this answers some questions.
There is some theoretical effect (could be improvement or degradation) due to bi-wiring. It relates to the small signal that exists at the common (-) terminal of the speaker as a result of the impedance of the speaker wire. If you don't bi-wire, the tweeter signal is referenced to the voltage at the low end of the woofer, which may be slightly different from the voltage (ground) at the amp. Because the woofer is a complex load (not purely resistive) this error signal is not just an attenuated version of the music signal.

All this is just theory, but it is the only scientific reason that I have found to suggest that bi-wire has any effect at all. Note that it suggests that only the return wire (-) needs to be doubled up, and also that use of very heavy wire will eliminate the effect (resistance goes to zero). In fact, this effect may explain why heavy wire sounds better for a mono-wire connection.

If one were to experiment with bi-wire, I suggest that you use very small wire (say #30) so as to aggravate the effect (when mono-wired) enough to be clearly heard.

PS: My Maggies are bi-wired. It was an experiment, using #24 wire for the tweeter so as to replace the 1 ohm tweeter padding resistor with cable resistance. It's hard to say if there was an improvement, but certainly no degradation so I have left these wires in place.
Zoya, it has always seemed to me that for your position (sorry to refer to it that way, I know it's not an original idea with you) to even stand a chance of making any 'sense', one must first buy into the proposition that in a biwire setup, the amp will somehow discriminate between which frequencies it sends through which cables - *and* that the so-called 'back-EMF' generated by the woofer will decline to find its way into the cable connected to the tweeter upon its arriving back at the amp's output terminals, even though at that point the two sets of cables are in intimate contact with each other.

I don't buy any of that, although I freely admit I'm not technically competent to scientifically evaluate all the arguments (much less Eldartford's post :-) It seems to me that even in a biwire setup, the tweeter and woofer sections will still 'see' each other - plus both runs of cable, whether or not the two runs are endowed with differing physical/electrical properties - within the overall amp/cable/speaker circuit.

Speaking of Eldartford, until recently I wouldn't have though twice about his passing comment on heavier-guage wire sounding better, all other things being equal (whether that was achieved through biwiring or simply employing a heavier single run). But that was before I brought in a set of Audience's Au24 SC for audition, wherein the wire for both legs of the connection plus all the dielectric and jacketing materials are bundled into a cable exactly 1/8" thick, or about the diameter of your average computer mouse cord. I think all the positive notice this product has been receiving is probably justified, and Audience's theory here, as I understand it, is that AC resistance, which they equate with inductance, is most important (along with capacitance) to minimize in an audio circuit - as opposed to DC resistance - providing that the wire guage is sufficient to handle the current-carrying demands made upon it.

I'm not qualified to speculate on Audience's theory of their product's operation, but though I'm still not finished in my testing, I can tell you that compared to my reference Satori SC (a fine cable - maybe even preferable for those seeking warmth - next to which the puny Au24 looks simply comical), bass response does not seem to have suffered (though its presentation is different), and top-to-bottom clarity and overall temporal integrity seem to have improved. (I should note, however, that my most positive impressions have been with the cable mated to my reference VTL tubed amps ; when I initially did this comparison using a McCormack SS amp and the same speakers, I thought I preferred the Satori overall, but I need to revisit this issue now that the cables are more fully broken-in.)
I will not even attempt to participate in the technical analysis of the merits of bi-wiring. What I want to add is that I can definitely hear a difference, and - yes - I have participated in 'blind' listening experiments to confirm this.

Of course, one cannot argue with those individuals that state that they can't hear a difference. If bi-wiring doesn't improve your sound, then don't spend $$$ to do it!
Zaikesman...True that Impedance (not just resistance) matters. However, low resistance is a big step in the right direction, and much easier and cheaper to do than Inductance minimization.

I still think that the best approach is to minimize everything with wires about one foot long! (Monoblock amps).

A theory is NOT a theory until proven true. Otherwise, they are called hypothesis or conjectures. Too many unproven claims are put out there to lure unsuspected consumers.
I don't buy zoya's theory for a minute. The frequencies we are talking about are so low that the wavelength of the signals is about 10 miles long. (3*10^8/20*10^3 = 15000 meters).
Therefore all points on the cable are at the same voltage, and see the same impedance, whether you biwire or not. I bet you could not measure the slightest difference between the signals at the HF and LF terminals when biwiring off a single amplifier.

The only time an amp sees different impedance is when you biamp, because it's only driving one part (HF or LF) of the speaker, and so the impedance curve to each amplifier is likely to be much more benign.

Biwiring without biamping may help in that there is simply more conductor, but I don't expect any effect beyond this.
Jetkitty: Your admirably honest post prompts me to remind anyone who may have read mine, that I am not talking about audition results, because my Thiels will only accept single-wiring by design. I'm just stating my reasoning for suspecting that anybody hearing a difference with biwire, will probably be doing so for reasons such as the increase in overall wire guage, rather than any stemming from biwiring as a supposedly superior connection topology per se.

BTW, it seems to me there is a nearly perfect method to test this proposition: Provided you have high-quality jumpers available (ideally they would be identical to the speaker cables, but I think the short length of the jumpers probably makes that point relatively moot), just do a test that leaves the biwire cables in place while simply adding and removing the jumpers at the speaker terminals. The results of that test could then be compared to taking the biwire cables and connecting them both to the same set of speaker terminals (like at the amp) with the jumpers left in place, and then finally with one set of the two biwire cable leads left disconnected at the speaker end. Obviously if the tests could be performed blind that might be nice, but I like to think that's optional for anyone who's made the effort to come to intellectual grips with the reality of the placebo effect and invest the time required to minimize its potential to bias the results.