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Bi-wiring describes a method of hooking up speakers to an amp. The speakers must support bi-wiring in order to do this (the speakers need a separate set of binding posts for the high end and low end). In a bi-wired setup, two sets of wires (often packaged within a single cable) run from the amp to the speakers - both wires are connected to the same point on the amp, but on the speaker end one is connected to the high input and the other to the low input. Pre-packaged bi-wire cables will specify which is the high set of wires and which is the low.


The theory on the advantages of bi-wiring is two fold. Part of the theory says that high frequency and low frequency signals have different wire requirements, thererfore splitting the signal as it leaves the amp and using appropriate wires for each signal brings audible improvements. The other part of the theory says that low and high frequency signals within the same wire will interact with one another, causing distortion.


You will get opinions from both sides regarding whether or not bi-wiring makes an audible difference (cables are a topic of much controversy). People can't even agree on exactly what an audible difference is, so I recommend that you find a way to try bi-wire cables risk free before commiting to a purchase (most audio shops I've deal with will let you try equipment for 30 days, and give you a full refund is you're not satisfied).


One thing to be aware of should you decide to audition bi-wire cables, is that many people claim that wires break in over time, and sound better after x hours of play. Once again, this is a very controversial topic for many reasons. Regardless of your beliefs towards break-in, I highly recommend taking as much time to audition new equipment as possible - it's the best way to make sure you're not making a snap decision, and even if your equipment never changes its sound over time, it does take time for your ears/brain to get used to any changes in the sound of your system. Once you've become accustomed to any change in sound, then reverting to the old equipment is usually a good way to decide for yourself if there's any real difference, and if so, if it's worth the price.


-Tweak
 

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Biwiring is a brilliant effort on the part of cable manufacturers to extort even more money from audiophiles than their already high margins on other cables. Tweak uses the term "theory" quite loosely in his post. In real science (as opposed to pseudo-science), for something to be called a theory, it should stand up to scientific inquiry. This process includes, but is not limited to, experiment, publication, and peer review. All available scientific inquiry on the subject of biwiring leads us to believe that it is snake oil.


Tim
 

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another practical reason for bi-wiring is that the simpler the impedance variations a voltage source (amp) sees the easier the load. Impedance is a function of frequency. The less frequency variation in each wire, the simpler the impedance, the smaller the load each wire presents to the voltage source or amp. Bi-wired speakers simply present an esier load to an amp. Or so I've been told

my 2 cents.


Thanks.
 

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Matt, my personal views on the subject aside, the total impedance seen by the amp, as a parallel circuit, would not differ. Also, a lower impedance brought about by larger and/or more conductors (lower resistance) would techniclly become a larger load, i.e, higher current, on the source.


Everything about bi-wiring depends on whether the wire has any impedance. If the conductors are large enough for the impedance to be 'negligible', then bi-wiring should have exactly the same effect as using a larger conductor (not that that is a bad thing, of course.)


I bi-wired for a combination of reasons: my amp has terminals suitable for bi-wiring (which Bob Carver suggests be used for this), I happened to have a reel of #14 laying around, and I wanted #12 (or larger) than #12 for the speaker runs.
 

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How do the frequencies know which wire to take?
 

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Tweak already answered that... the cables come marked from the manufacturer. ;)
 

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Only you can decide if bi-wiring is worth it to you.


In my stereo it made a night and day difference (martin logan, aragon amps, adcom 750). With the bi-wiring producing WAY too much bass, so I don't bi-wire.


It was a simple try for me, go pick up some 12 ga wire and give it a shot.
 

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Quote:
Originally posted by Larry Fine
Matt, my personal views on the subject aside, the total impedance seen by the amp, as a parallel circuit, would not differ. Also, a lower impedance brought about by larger and/or more conductors (lower resistance) would techniclly become a larger load, i.e, higher current, on the source.
Larry, I may have erred by using the adjectives smaller and easier when I meant simpler to describe the impedance characteristics of a bi-wired speaker as opposed to a non bi-wired speaker. And I'm not referring to total impedance but impedance variations. As I understand it, every speaker has a characteristic impedance frequency curve that creates a load with varying impedances for amplifiers powering them. The greater the variations the more problematic it is for the amp to accurately reproduce the waveform. The idea that bi-wiring simplifies impedance variations caused by speaker impedance frequency curves by localizing hi and lo frequencies and the impedance variations they cause to a particular wire seems plausible to me. As localizing hi and low frequencies and the impedance variations they cause to separate amps in a bi-amped speaker also seems believable. Bi-wiring is just a poor mans version of bi-amping.


Chu,

As per your question. I believe a combination of crossovers in series and speaker impedance frequency curves determine which frequencies become common to which wire in a bi-wired system.
 

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Matt, once you get passed the common point, the speaker terminals, then yes, the separate impedance curves of the speaker sections are imposed only on the wire feeding each section. However, the two curves add to be exactly the same to the amp's output stage; the only difference is that the effective wire impedance is a hair lower.


Chu, the voltages of all frequencies are present at all speaker terminals. Only the impedances presented by each terminal pair accross the frequency range determine the resulting current at each frequency band. High frequency currents don't flow through the low section's wires simply because the impedance is too high at high frequencies, and vice versa.


As a loose analogy, there is 120 volts present at every receptacle in your home, but the current flow is dependent upon the resistance of the load (and wires, connections, etc.), the only difference being it all happens at 60 Hz.


But if you add, for example, X-10 signals to your power lines, they, too, are present at every electrical outlet, but only have effect where they pass through high-pass filters built into X-10 equipment, and the 60 Hz power doesn't flow into the X-10 equipment because those same filters block the 120 volts.
 

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Quote:
Originally posted by Larry Fine
Matt, once you get passed the common point, the speaker terminals..., the two curves add to be exactly the same to the amp's output stage
I don't have the technical background to argue this point. But one thing I've learnt is never to assume that vectors (impedance frequency curves in this case) sum in a predictable manner.


I should also mention that speakers setup for bi-wiring/bi-amping have better crossover networks than speakers that aren't. This may contribute to the reason why I get much better base definition when I bi-wire.


Thanks.
 

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Hey guys,


I am just a simple man and don't really understand the EE aspect of a lot of elements that make up a quality HT experience. Don't get me wrong, I have a good knowledge of impedance, freq. response, standing wave effects and other factors...but I don't actually know the advantages or disadvantages of bi-wiring.


That being said, I have had a very positive response from bi-wiring. Without using my receivers MCACC function, only measuring from an spl meter with pink-noise test signals, I have had some noticeable gains across a couple of frequencies. The most noticeable gains were around 80khz and 10,000 khz. I had between a .3 and .5 increase in frequency. This may well be due to my use of only 14ga speaker cable, but the difference is recordable.


I did not use a specially-created bi-wiring speaker cable...merely "monster-cables" which I connected to the receiver using both banana and spades.
 

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Coach, if you measured a difference in the output, that means you were using insufficient gauge wire to start with. All you are getting from bi-wiring is an effectively larger gauge wire with a lower impedance. Which, of course, is a good thing.


The ideal speaker wire would have a resistance of 0, and an impedance of 0; since we live in the real world, not the world of theory, we want fat copper wire to transmit the signal (copper is a very good conductor that happens to be relatively inexpensive).

I bi-wire my CC because I had extra wire laying around. I'd never go out of my way to spend extra money to biwire; there are better places to spend money to improve sound, like acoustic treatments, that actually will make an improvement. :D


Some physics or EE classes would allow many people to spend money on parts of their systems that do make a difference, like speakers, preamps, amps, and most importantly, software. If P.T. Barnum were alive today, he'd sell speaker wire and various other cables to idiotophiles, er, I mean audiophiles. :D


**dons flame retardant suit and runs away**


Sorny
 

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Quote:
Originally posted by spongebob
And does it really matter? Can you hear a difference?


thx


bob




I bi-wired my 805Nautilus and I did hear difference.I think that if you have the possibility to bi-wire then do it.Try it for some time and if you do not hear the difference then turn back the cables(as I know there is a return policy in most cases).Only your own ears can decide.

:D
 

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I'm so disappointed. I thought this was the AV SCIENCE forum. There is no science to bi-wiring.
 

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Quote:
Originally posted by NightHawk
I'm so disappointed. I thought this was the AV SCIENCE forum. There is no science to bi-wiring.
Brush up on your advanced algebra and laws of electricity before you read this: http://www.st-andrews.ac.uk/~www_pa/...ire/Page1.html


Courtesy of a previous discussion on this forum about bi-wiring
 

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Ian Colquhoun, the founder and chief engineer of Axiom Audio, has publicly stated that their flag-ship M80 floorstanders feature the "bi-wireable" binding posts SOLELY for the marketing reasons. He, together with the former editor of Sound & Vision magazine Alan Lofft, explicitly declines any technical benefits of bi-wiring. But Ian obviously does not want the sales suffer just because there is no bi-wireable connectors.
 

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Not being an EE or speaker/cable designer, I have a question. When bi-wiring speakers, aren't you, via removal of the jumpers on the terminals, bypassing the (or one of the) cross-over(s)? This would SEEM to indicate a sonic difference in that the drivers affected by the cross-over would then be able to play a greater range of tones per driver (not being limited by the cross-over), thus changing the sonic signature of the speaker. Make sense?


AND whether that modified sound is good or bad is wholly up to the listener's ears. . . . :)
 

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No, this does not bypass the crossover. The input to the high-pass and low-pass filter network sections are just locally seperated, hence, no sonic impact.
 
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