Benefit of bi-wire speakers? - Page 2 - AVS Forum
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post #31 of 273 Old 01-18-2012, 05:43 PM
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Also, kiwi, your conclusion is faulty. The amp output is full-range on both connections, and the crossover filters it before sending it to the speaker driver.

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post #32 of 273 Old 01-18-2012, 05:47 PM
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I do understand. Richard Vandersteen does too. He designs them for a living.

Richard Vandersteen has designed and built the finest speakers in the world for over 40 years by the tens of thousands, as a Stereophile article and interview documented a couple of years ago. You can look it up and read it.

He very strongly recommends Bi-wiring, and explains why on his website. If you actually are interested in the opinion of one of the foremost experts in the field, that is where you will find it. If you are not, then that is the end of it.


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Originally Posted by sivadselim View Post

OK, you're a Martian who doesn't understand how a biwirable/biampable crossover and speaker operates.

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post #33 of 273 Old 01-18-2012, 05:54 PM
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Quote:
Originally Posted by beaveav View Post

The amp output is full-range on both connections

Remember... electricity works off demand. The amp does not "output" to the end of the cables. Just like my car battery analogy.


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and the crossover filters it before sending it to the speaker driver.

And as each side of the crossover is only powering certain frequencies/drivers, then the draw in its cable is only those frequencies/drivers that the crossover is powering.
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post #34 of 273 Old 01-18-2012, 05:55 PM
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I think AJ pointed out that the "appeal to authority" argument holds no water, so why use it again?

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Quote:
Originally Posted by commsysman View Post

Please go to the Vandersteen website and look up Richard Vandersteen's discussion of the benefits of bi-wiring. It will almost certainly answer your questions, and if not, he will answer your questions on his running Q and A pages when you fill out the form and submit it online; he is very good about responding promptly.

Thank you for answering my question with a Red Herring, as it does indeed provide your answer.

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Originally Posted by commsysman View Post

He has designed and built some of the finest speakers in the world over the past 40 years, and his Model 2 is considered to be the best-selling high-end speaker of all time. If he isn't an expert, nobody is!
If you don't believe what he says on the subject, you are definitely not a person that can be brought to the truth easily.
He strongly recommends bi-wiring and his explanations make sense to me both as an engineer and as a listener.

It is a bit odd that after 30 self proclaimed years of EE, you wouldn't know what Appeal to authority, Red Herrings, etc, etc. are.
Or how to scientifically explain the audible benefits of buywiring....though psychoacoustics falls outside your claimed realm.

But then again we are in cyberspace, so as such....I'm Batman.

cheers,

AJ
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post #36 of 273 Old 01-18-2012, 06:02 PM
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kiwi, no need to remind me how electricity works.

"And as each side of the crossover is only powering certain frequencies/drivers, then the draw in its cable is only those frequencies/drivers at the crossover is powering."

That is not how it works. If I have an amp outputting full-spectrum audio (say 20Hz to 20kHz), it will output that regardless of the load. If the load is a woofer with a low-pass filter (for its crossover), then the entire audio spectrum is on the cable, the low-pass filter then reduces the spectrum to its passband, and that is fed to the woofer. If we're talking about the high frequency range, it will be a tweeter with a high-pass filter before it (as its crossover). Again, the cable to the speaker will carry the full spectrum. The crossover will high-pass filter that before it goes to the tweeter.

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post #37 of 273 Old 01-18-2012, 06:14 PM
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Quote:
Originally Posted by beaveav View Post

Again, the cable to the speaker will carry the full spectrum.

A cable will not carry a load other then the draw of the component that it is powering.

If you have a 100w light bulb and a milliwatt car alarm both connected directly to the terminals of a car battery with their own individual run of wire... and you measured the draw of each wire... would you get the same load on each wire?
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post #38 of 273 Old 01-18-2012, 06:19 PM
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Originally Posted by kiwi2 View Post

Remember... electricity works off demand. The amp does not "output" to the end of the cables. Just like my car battery analogy.

Honest question then. If this is the case, then how is it possible to overpower a speaker if the amp will only deliver "on demand"? If this is true I should be able to hookup a 10KW amp and set the gain on max (assuming I'm not clipping at the input or output stages) and not worry about blowing a 500W properly built sealed sub assuming I have the proper hp/lp filters in place correct?
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post #39 of 273 Old 01-18-2012, 06:20 PM
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Of course not, kiwi.

But that has little to do with what we're discussing here. You're using an example of DC current division, while we're talking about how spectrum is divided.

In your case, you have a DC voltage source, two resistive loads, and therefore two DC currents to those loads. Yes, the individual currents will split according to each load - Kirchoff's current law.

The analogy does not carry over to spectral splittling with complex impedance loads and active sources (amplifiers). That's the point you're missing.

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post #40 of 273 Old 01-18-2012, 06:21 PM
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Quote:
Originally Posted by kiwi2 View Post

Likewise for two individual cables feeding off each side of a crossover on a speaker. Each cable's load is only the draw of the frequency it is attached to.

And those cable are connected, in parallel, to the exact same amplifier.

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post #41 of 273 Old 01-18-2012, 06:27 PM
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Quote:
Originally Posted by sivadselim View Post

And those cable are connected, in parallel, to the exact same amplifier.

Right. Meaning, in electrical engineering terms, that the cables are all the same node. And that means they will all have the exact same signal on them.

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post #42 of 273 Old 01-18-2012, 06:37 PM
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Monowiring an amp to one pair of binding posts with the binding straps in place versus biwiring the same amp to both pairs of binding posts with separate cable runs.

Let's disregard any difference in cable gauge and assume the same distance. Or, if that bothers you, we can make the monowired circumstance be with 11g wire and the biwire with 14g.

Both connections represent, electrically, the same parallel connection to both pairs of the speaker's binding posts. The only difference is the length of the wire used to make the parallel connection in the biwired situation versus the length of the binding strap that is used in the monowired situation.

So, the amplifier. Does the amplifier "know" or "see" a difference between the two connection schemes? No, it doesn't.

And the crossover. Does the speaker's crossover "know" or "see" a difference between the two connection schemes? No, it doesn't. And neither do the drivers "know" or "see" what sort of connection is being made to the crossover's binding posts.

So, the only place where there is a difference is in the cable run and/or the binding strap. Now, you can argue that that can make a difference, electronically, but at the distances and wire gauges we are talking about, it can't. And doesn't. And you can make some really esoteric arguments about what is happening in the two cable runs versus a single cable run and the binding strap, but none of those fly either.

Now, if your amp were on Mars and your speakers on Earth, there might be a difference between those two scenarios over that distance, depending upon the gauge of wire you were using.
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post #43 of 273 Old 01-18-2012, 06:41 PM
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Quote:
Originally Posted by duc135 View Post

Honest question then. If this is the case, then how is it possible to overpower a speaker if the amp will only deliver "on demand"? If this is true I should be able to hookup a 10KW amp and set the gain on max (assuming I'm not clipping at the input or output stages) and not worry about blowing a 500W properly built sealed sub assuming I have the proper hp/lp filters in place correct?

An amp sees a speaker as a way to earth. When you turn up the volume you are allowing the amp to flow more current to earth. If you disconnect the speaker, then no current will draw through the cable no matter how much you turn the volume up. It's all about demand upstream.
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post #44 of 273 Old 01-18-2012, 06:44 PM
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Quote:
Originally Posted by sivadselim View Post

And those cable are connected, in parallel, to the exact same amplifier.


They won't be in parallel if they are connected to different components with different draw.
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post #45 of 273 Old 01-18-2012, 06:45 PM
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Quote:
Originally Posted by commsysman View Post

I do understand. Richard Vandersteen does too. He designs them for a living.

Richard Vandersteen has designed and built the finest speakers in the world for over 40 years by the tens of thousands, as a Stereophile article and interview documented a couple of years ago. You can look it up and read it.

He very strongly recommends Bi-wiring, and explains why on his website. If you actually are interested in the opinion of one of the foremost experts in the field, that is where you will find it. If you are not, then that is the end of it.

I am very familiar with THIS page. I have even cited it in the past in discussions regarding why manufacturers include biwirable/biampable binding posts on their speakers. But you know what? It's full of fallacious information.

There are many other reputable speaker manufacturers that recommend biwiring their speakers.

And arguments can be made in support of there being a difference in a biwired speaker versus a monowired speaker. But you haven't made them and what you have said is not true.

Here is some reading for you:
PART 1
PART 2

"All men are frauds. The only difference between them is that some admit it. I myself deny it."
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post #46 of 273 Old 01-18-2012, 06:46 PM
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Uhm, that's the very definition of being in parallel.

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post #47 of 273 Old 01-18-2012, 06:47 PM
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Quote:
Originally Posted by beaveav View Post

The analogy does not carry over to spectral splittling with complex impedance loads and active sources (amplifiers). That's the point you're missing.

The lower frequencies demand higher current loads than higher frequencies. Different frequency drivers will have different current loads... thus the separation.
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post #48 of 273 Old 01-18-2012, 06:48 PM
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Quote:
Originally Posted by kiwi2 View Post

They won't be in parallel if they are connected to different components with different draw.

It still represents the same parallel connection to the crossover's high and low section binding posts as would be there with a single wire run and the binding straps connecting the posts. Sorry, but there's no way around that.

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post #49 of 273 Old 01-18-2012, 06:52 PM
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Quote:
Originally Posted by kiwi2 View Post

The lower frequencies demand higher current loads than higher frequencies. Different frequency drivers will have different current loads... thus the separation.

This is irrelevant to a biwiring situation. The single amplifier sees the exact same load whether biwired or monowired with the binding straps in place. You can TRY and use this fact when making an argument in favor of passive biamping but it's irrelevant there, too, actually.

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post #50 of 273 Old 01-18-2012, 06:54 PM
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Quote:
Originally Posted by kiwi2 View Post

The lower frequencies demand higher current loads than higher frequencies. Different frequency drivers will have different current loads... thus the separation.

Lower frequencies don't necessarily demand higher current loads. It might be true in general, but I have seen some speakers where the impedance is lower in the high-frequency region than in the low-frequency region, meaning they draw more current in the highs than in the lows. But that doesn't matter in this discussion either.

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post #51 of 273 Old 01-18-2012, 07:28 PM
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Quote:
Originally Posted by kiwi2 View Post

An amp sees a speaker as a way to earth. When you turn up the volume you are allowing the amp to flow more current to earth. If you disconnect the speaker, then no current will draw through the cable no matter how much you turn the volume up. It's all about demand upstream.

Ok, but if it's all about demand upstream then I would never be able to overpower a 500W sub with a 10KW amp since the sub will only demand 500W correct? This is the logic, yet I've heard of cases where subs were blown due to being overdriven by the amp. This is the part I do not understand. If it's beyond this discussion then just say so and I'll drop this line of questioning.
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post #52 of 273 Old 01-18-2012, 07:28 PM
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[Original source of this image is wikipedia, IIRC, but I can't link there because they are on 24 hr strike to protest SOPA and PIPA.]:


The proper term for biwiring is "using longer than average jumper straps"!

There's no difference to the block diagrams of normal vs. biwiring and buy (more) wire proponents who try to claim that this simple "lumped element model" doesn't tell the whole story are completely full of BS, based on the frequencies we use for audio and the lengths of wire we might use, even in a gigantic mansion hundreds of feet long.

When you run a wire tens or hundreds of miles long, then transmission line theory applies, but for our living rooms? Not a chance. This simple block diagram does tell the whole story. There's no audible consequence from splitting the signal six inches away from the speaker vs six feet, as long as the L, C, and R values are maintained the same for both.

[A possible exception where there could be audible consequences (simply because these values aren't kept the same for both), would be for people who are using a dangerously thin gauge wire run to their speakers. When they double up their wire they are, of course, effectively using a much thicker wire with double the number of copper strands running the length of their living room, and the lowered resistance of this thicker wire may have audible consequences in such a scenario. Of course if they simply had used a single run of thicker wire, from the get go, then there'd be no difference.]

Other forms of obfuscation they often attempt to pull, are arguments regarding "skin effect", reflections, dielectric absorption or "soakage", etc, but don't fall for any of it. In the over half century that speakers with biwirable terminals have been on the market (actually made for other purposes, such as active bi-amping) , not a single paper has ever been published to support the claim that biwiring has any audible consequences. All we have are anecdotal stories under uncontrolled circumstances (sighted) and silly theories as to why it "could" make a difference, often promoted by the audiophile mythology based press. [Who unfortunately dominate the magazine stands these days.]

On the rare occasion where people do measure subtle electrical differences from biwiring, they almost never take into consideration this "double thickness" advantage their "bi-wire" system has and instead insist the difference is because "All the high frequencies know to travel only through this top wire (across the living room) and of course all the low frequencies know to travel only along the bottom wire." They seem to not understand that the "frequencies" have no intelligence and haven't even passed through a crossover yet at this stage!
---

"At audio frequencies, speaker cables are not transmission lines. They are merely cables, with inductance, capacitance and resistance. Despite popular belief, they are bereft of any magical properties, only physics."

Source

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In A/V reproduction accuracy, there is no concept of "accounting for taste". We don't "pick" the level of bass any more than we get to pick the ending of a play. High fidelity is an unbiased, neutral, exact copy (or "reproduction") of the original source's tonal balance, timing, dynamics, etc..

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post #53 of 273 Old 01-18-2012, 07:42 PM
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Quote:
Originally Posted by kiwi2 View Post




And as each side of the crossover is only powering certain frequencies/drivers, then the draw in its cable is only those frequencies/drivers that the crossover is powering.

Correct. But whether the cable split occurs at the amplifier or at the speaker the result is exactly the same. If you really want to get to the crux of the matter it's explained by the Superposition Principle.

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post #54 of 273 Old 01-18-2012, 08:10 PM
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Originally Posted by duc135 View Post

Ok, but if it's all about demand upstream then I would never be able to overpower a 500W sub with a 10KW amp since the sub will only demand 500W correct? This is the logic, yet I've heard of cases where subs were blown due to being overdriven by the amp. This is the part I do not understand. If it's beyond this discussion then just say so and I'll drop this line of questioning.

Do you mean removing the 500W amp from the sub and replacing it with a 10KW amp? You simply then have a 10KW sub. The question is - will the driver handle 10KW? Maybe for a couple of seconds as 10KW flows through it until something melts and the circuit to earth is broken. Then there is no current draw. The demand on the amp is then zero and the flow is zero.

Or you could have your 10KW amp connected to the woofer, but with no or very low audio signal... so there is very little demand for current and subsequently low draw and the amp only puts out a couple of watts. All would be fine even though you have it connected to 10KWs. Connecting to 10KW does not mean 10KW of draw unless there is demand for it. If 2W of power is all that is required then that is all that will flow.
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post #55 of 273 Old 01-19-2012, 02:30 AM
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As long as you continue to base your arguments on an incorrect understanding of basic electrical circuit fundamentals, the conclusions you arrive at will of course be incorrect. I hope that the following explanation will help you arrive at a better understanding:

Within a speaker that is properly designed for bi-wiring, there are two completely separate circuits attached to the two sets of terminals, an HF circuit (consisting of speakers and electrical components) and an LF circuit (consisting of different speakers and electrical components).

In the case of the LF circuit, the HF current cannot flow because it is blocked by electrical components that have a high reactance to HF (inductors). You seem to think that the HF current can somehow flow through the wires going to the LF terminals even though the circuit has high reactance to HF internally and blocks this flow.

This would imply that the HF current can flow as far as the speaker even though there is nowhere for it to go when it gets there. This is a fundamental misunderstanding of an electrical circuit and the difference between current and voltage. The wires are in series with the internal LF circuit, and if the HF current cannot flow within the LF circuit of the speaker (and it cannot), then it cannot and will not flow in that pair of connecting wires either.

The fact that all frequencies are AVAILABLE as VOLTAGE at the power source (the amplifier) terminals does not imply that all frequencies will flow in the form of actual CURRENT in every wire connected to them. There must be an available path for those frequencies to flow at the other end of the wires or CURRENT will not flow in the wires at those frequencies.

The inverse of all of the above obviously is true of the HF circuit.

My credentials have nothing to do with anything. The fact that you apparently have an incorrect understanding of basic electrical principles is causing you to misunderstand the entire concept of bi-wiring, which is completely accepted and well-understood in the audio industry (not that everyone agrees that it has sonic merit).

Speaker designers and manufacturers go to the added expense and trouble of separating the speaker internally into two separate circuits precisely so that the LF current and HF current can be provided separately by two separate pairs of wires, each of which then carries a lower current as well as separate groups of frequencies.

It is rather illogical to suggest, as you do, that they would do this if it were not possible to accomplish the desired result. They actually DO understand the electrical theory correctly, and it IS indeed technically correct that bi-wiring does what it is supposed to do.

Whether this makes an audible difference is disputed by highly qualified people who all have good credentials, and yet there are still two groups that disagree. There is no shortage of respected experts in both camps, yet someone has to be wrong. I don't think this issue will be resolved anytime soon.




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Again, your credentials and experience does not automatically make you right. It gives you more credibility, but definitely not the final word. We are all human and are capable of error and inaccurate recollection.

What you point out about LF/HF circuits are correct for the connection between the XO and the driver, but is incorrect for the connection between the amp/receiver and the XO which is what bi-wiring involves. There is nothing in that part of the chain that could control which wire gets what frequencies. The signal leaving the amp/receiver is full bandwidth on both wires (with the exception of any filtering by the receiver itself, but that filter applies to all wires connected to the post in discussion) until it gets to the XO which is located inside the speaker box.

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post #56 of 273 Old 01-19-2012, 03:42 AM
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The failure mode when subwoofers "blow" , 90% of the time, is that the transistors in the subwoofer amplifier short out and the DC power supply current is then directly applied to the speaker coil, and the resulting high DC current melts the voice coil.

It has nothing to do with the available rated power of the amplifier.

In some cases physical deterioration of the cone surround may occur, causing the voice coil to become physically damaged due to scraping on the magnet structure. This can eventually cause the voice coil to short out and fail.

It is worth noting that power is only the mathematical product Voltage times Current, which sometimes seems to be misunderstood; no current flow, no actual power. Current FLOWS; power does not flow.

This is different from a power RATING, which is the operating voltage times the maximum current flow available when the load actually draws such a current.




Quote:
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Do you mean removing the 500W amp from the sub and replacing it with a 10KW amp? You simply then have a 10KW sub. The question is - will the driver handle 10KW? Maybe for a couple of seconds as 10KW flows through it until something melts and the circuit to earth is broken. Then there is no current draw. The demand on the amp is then zero and the flow is zero.

Or you could have your 10KW amp connected to the woofer, but with no or very low audio signal... so there is very little demand for current and subsequently low draw and the amp only puts out a couple of watts. All would be fine even though you have it connected to 10KWs. Connecting to 10KW does not mean 10KW of draw unless there is demand for it. If 2W of power is all that is required then that is all that will flow.

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post #57 of 273 Old 01-19-2012, 04:04 AM
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I'm sure many have read but for those who haven't.
I always like to read the "ten biggest lies in audio" . Humorous & informative.
Be neat to see an updated list but it remains relative.

Check it out:
http://www.theaudiocritic.com/back_i...ritic_26_r.pdf
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post #58 of 273 Old 01-19-2012, 04:33 AM
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If you want to read a lot of lies, half-truths and distortions about audio, The Audio Critic is certainly a good place to find them. That publication is the work of a person with some strange agendas and a desire to tilt at windmills, even when the windmills don't need anyone to bother with them.


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I'm sure many have read but for those who haven't.
I always like to read the "ten biggest lies in audio" . Humorous & informative.
Be neat to see an updated list but it remains relative.

Check it out:
http://www.theaudiocritic.com/back_i...ritic_26_r.pdf

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post #59 of 273 Old 01-19-2012, 05:09 AM
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As an electrical engineer with quite a bit of analog circuit design experience I have to agree 100% with everything commsysman is stating. The issue here is a lack of understanding of how crossovers work.

Let's say that we believe what Richard Vandersteen is saying. I think his reputation warrants this. More specifically, that the magnetic field interactions between low frequency and high frequency signals can cause distortion or other issues which result in a degradation of sound quality. According to Ampere's law and the refined Maxwell equation which correct some flaws in the original law, a current must be flowing to create a magnetic field. If you separate the HF/LF crossovers and wires (bi-wiring), then the HF crossover will have a high impedance to LF signals. This prevents any low frequency current and consequently result in no magnetic field related to the low frequency signals in the HF wire. Assuming you have adequate spacing between the high frequency and low frequency cables you are creating a different circuit with different properties (decoupling the magnetic fields of HF/LF signals). The same goes for the LF wire (separating any field from HF signals).

This is without a doubt founded in fundamental theory and a reason to bi-wire (or bi-amp). How much of an audible difference this really makes is another argument entirely. However, to state that there is no theoretical justification for this is nonsense.

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As long as you continue to base your arguments on an incorrect understanding of basic electrical circuit fundamentals, the conclusions you arrive at will of course be incorrect. I hope that the following explanation will help you arrive at a better understanding:

Within a speaker that is properly designed for bi-wiring, there are two completely separate circuits attached to the two sets of terminals, an HF circuit (consisting of speakers and electrical components) and an LF circuit (consisting of different speakers and electrical components).

In the case of the LF circuit, the HF current cannot flow because it is blocked by electrical components that have a high reactance to HF (inductors). You seem to think that the HF current can somehow flow through the wires going to the LF terminals even though the circuit has high reactance to HF internally and blocks this flow.

This would imply that the HF current can flow as far as the speaker even though there is nowhere for it to go when it gets there. This is a fundamental misunderstanding of an electrical circuit and the difference between current and voltage. The wires are in series with the internal LF circuit, and if the HF current cannot flow within the LF circuit of the speaker (and it cannot), then it cannot and will not flow in that pair of connecting wires either.

The fact that all frequencies are AVAILABLE as VOLTAGE at the power source (the amplifier) terminals does not imply that all frequencies will flow in the form of actual CURRENT in every wire connected to them. There must be an available path for those frequencies to flow at the other end of the wires or CURRENT will not flow in the wires at those frequencies.

The inverse of all of the above obviously is true of the HF circuit.

My credentials have nothing to do with anything. The fact that you apparently have an incorrect understanding of basic electrical principles is causing you to misunderstand the entire concept of bi-wiring, which is completely accepted and well-understood in the audio industry (not that everyone agrees that it has sonic merit).

Speaker designers and manufacturers go to the added expense and trouble of separating the speaker internally into two separate circuits precisely so that the LF current and HF current can be provided separately by two separate pairs of wires, each of which then carries a lower current as well as separate groups of frequencies.

It is rather illogical to suggest, as you do, that they would do this if it were not possible to accomplish the desired result. They actually DO understand the electrical theory correctly, and it IS indeed technically correct that bi-wiring does what it is supposed to do.

Whether this makes an audible difference is disputed by highly qualified people who all have good credentials, and yet there are still two groups that disagree. There is no shortage of respected experts in both camps, yet someone has to be wrong. I don't think this issue will be resolved anytime soon.

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post #60 of 273 Old 01-19-2012, 05:20 AM
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One other quick thing I wanted to add. Anyone that is doubting the concept of separating these magnetic fields (HF and LF) go take a look at any crossover design on a moderate to high end speaker system. You should notice that the inductors (most likely air core) are geometrically perpendicular to each other. This is to eliminate the magnetic field interaction between the HF and LF signals.
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